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1951

Studies on the Germination, Production, and Distribution of Studies on the Germination, Production, and Distribution of

Johnson Grass Seed in Certain Areas of Louisiana. Johnson Grass Seed in Certain Areas of Louisiana.

Ruth Patterson Phillips Louisiana State University and Agricultural & Mechanical College

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Recommended Citation Recommended Citation Phillips, Ruth Patterson, "Studies on the Germination, Production, and Distribution of Johnson Grass Seed in Certain Areas of Louisiana." (1951). LSU Historical Dissertations and Theses. 7989. https://digitalcommons.lsu.edu/gradschool_disstheses/7989

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studies on the a m m m m , mmnim, m distribution of johnson m m m m m certain m m m Louisiana

A Dissertation

Submitted to the draSuati Faculty of the Louisiana State University and

AgriciCLtural and Ifeehanical Golleg**« partial Ihzlfilliaent of the s qtiireiffl&nta for the degree of

Doe tor of ItoilosaphyIn

The Department of Botany, Bacteriology, and P la n t e t h o lo g y

b yRuth Patterson Phillip®

B*A*, Louisiana State University, 193$ M.S., Louisiana State University, 1943

A u g u s t, 1950

UMI Number: DP69367

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MANUSCRIPT THESES

Unpublished theses submitted for the master*s and doctor*s degrees and deposited in the Louisiana State University Library

are available for inspection* Use of any thesis is limited by the

rights of the author. Bibliographical references may be noted, but passages may not be copied unless the author has given permission. Credit must be given in subsequent written or published ??ork.

A library which borrows this thesis for use by its clientele is expected to make sure that the borrower is aware of the above

restrictions*LOUISIANA STATE UNIVERSITY LIBRARY

S864

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tabie of c o m m1 ACKNOWLEDGMENTS * * * * * * *

ix m m m ........................ *. .. vtiXXX INTRGDUQTIGK * • • . . . . * * * * * * * ♦ • * * . * * 1X? HESTGRXCift. REVIEW * * * * * * .......... * * * * * * 3v mamxals m methods . . . . . . . . . . . . . . . . IX

Gemination of Johnson Grass Seed . • • • * . . . . XIClonal Studies of Pollen and Seed Production t » » • 14Studies on the Distribution of Johnson Grass

Seed in the Soil • • * • * * • • • • • • • « • * 19Johnson Grass Seed Recovered Between the lm£

Sheath and Stalls of Sugarcane * * * * * * * * * * 21i n studies m « gmxnaxm o f jgmmow, m m m m . , , 23

Prelfoitinary investigations of Factors AffectingSemination of Johnson Gmsa Seeds « » • • # « « 23

Further Investigations of Factors XnflueECingthe Germination of Johnson Grass Seed * * * * * * 30

Gemination of SsrcjiLas of Johnson Grass Seedfrom Golleotlone * • # # « « * * » * » * • * * * 41

V II ILQNAL STUDIES OF SEED AND POLLEN HQDUCIIGN * * * * * 59v in DismxBprxc® of Johnson grass seed in the soil * , . * 72

Studies of Johnson Grass Seed As a Soil Populationin the Sugarcane Areas of Louisiana * * * * * * 72

Johnson Grass Seed Recovered Between the leafSheath and Stalk of Sugarcane • • * » • * • • • * 25

K DISCUSSION . . . . . . . . . . . . . . . . . . . . . 90X 5UMMAKX . ............................ * * . * * 96XX BIBLIOGRAPHY . . . . . . . . . . * * * * * ....... WXXX AUTOBIOCfflAFHI . . . . . . . . . . . . . . . . . . . . 100XIII LEGEND FOR PLATES * * . * ......... * Id

ill

i*m of f M M Peg©X Percentage Gemination of Johnson Grass Seeds with the

Glumes Bmoved, Incubated at Several Constant Tempera* tea® for 7 days * * * * * * * . . . * » * , „ » . , * * 2 4

II Percentage CtemJLnatiem of ■ Johnson Graso Seed with the(Eraes on, incubated at Several Constant apd Alternate lag Temperature Conditions for 10 d ys. * • • * » • • • 24

HI Modifications of Gei ainatian Itementages by VariousMechanical Treatiaoiits of the Olme® and Caryopses* * * * 26

IV (termination of Johnscm Grass Seed Pitring inWater and at Alternating Temperatures Thereafter « » * * 26

? Percentage Germination of Johnson Grass Seed AfterTreatment with Several Chemical® in. Solution for 12 Honrs Previous to taminaiiaa at Alternating Temperate©® for 10 days* • • • • • » « • * « * • * • * &

11 Gemiiwticin Percentage® of Johnson Grass Seed 4 PaysAfter Treatment with Certain Chemicals for 12 tars* * * 32

111 Percentage Gemination of Johnson Grass Seed When Solutions of Ptptnd $23 Were Used to Moisten the Substrate • • • • • * » • . • * ' • » » « * , « » # * » 33

VIII Percentage (termination of Johnson Grass Seed When a &taH Quiu&ity of Different Soils was Added in the Petri Dishes • * » » • • * , * * • * , * « # » • . * • . 34

IX BemLte Obtained by Ctermlnatlos of 2 Collections of John* son Grass Seed in the Soils from IS Plantations in 1947. 35

X Studies of the Effect of Soils on tea Cteminfitim ofJohnson Grass Seed in the Fall of 194& and of 1949 . . . 36

XX Summary of 3 Teste of Effect of Soils m Ge&d&abictt* • 36XII Johnson Grass Seedlings appearing abwo (leomtu fro®.

Depths in two Greenhouse Teats in 1947 and 194&* • * • * 37XIII Percentage Gemination of Johnson Grass Seed after

ftmrtal in tbs • • * • • * • * . * • • • • * • ♦ • • 3 9XI? Germination as Influenced by Trsatsaent with 29/ 0 after

Two tears of Burial in the Soil as Compared to Two tears of Air*$torage» ........ • 40

it

XV Gemination ofJoMatm Grass Seed Collected frc& 98'Area* in the Sugarcane Belt la the M X of 1947# « • * • A $

OTE Germination *f Seed Collected la the Spring, Susaae**m mi Of 1948 «nd 1949 .................. 45XVXX longetity of Air-Stored Seed Celleeted la 194V And

JVOftv if. JitiMAkjliAMtoAf Mk> aO-.fci.Jl SS . jBjflt%mriltim*wS$l HI Imw5wOII*II Soil'* • • « • • • • • • • • ■ • • Sixv i l l Qernination of Seed or Johnson Grass Gelleotea from -

Si* Area* of Louisiana la 1947, 1948 end 1949* * * * • • %XXX Scant* of Seaelle lloreta tw the IteteratnAtion of the

Percentage fitlt Mature Caryopeee, • • • • • , • • • • • 5 9XX M io i Production of 50 Clones of Johnson (tetss In 1949

at Batoa Rouge, M&eiiwm • • • • • • • • • • • « • • • 6am&EL%& ws S fltfX AH0 C^p ll PouU IB S vi<S0l 0 f JGilllflOfcl O l® 80

Areas of Louisian* During 1948 and 1949 • 64XXII Comparison of Seed Production by Johnson Crass Clones

lAon Self PoUlnated and Vhorn g&em HLlliaaled. • • . • • 66XXHI Comparison of Actual and Bstimated heights of Seed

f t rc n dona* • • • • • • • • • • • • • • • • • • • , , , 6 S

XXXV Average Measurement* and Average Might of Seed* fromS AIm*** iSOojLonee • • • • • • • • • • • « • • , • • • • • • • • «oc>XXV Germination of Seed fTcm * dene* Selected In 1948 • • • 70

T,

XXVI Population of Johnson Crass seed in Soil Samples fromthe Sugarcane Beli in 1947 • • • • * • • • • • • • « • • 73

XXVXX number of Seedling* Geminating from St. BelpfeineSoil f*m Different Depths in 1947 • • • • • • • • • • • 74

w a n Germination of Johnson Grass Seed in a Sugarcane Heldat St* Dolphins Plantation from 1948 ijhnmgh Sammy,1950. ........ 79

«i* araniaNi increase in uorm&nei&dn or «ronnson crassSeed After Ovorwlnterlng in Soil • • • • • • • • * • • • 76

XXX GeimdJwiMlity of Seed Overwintering in Soil in 1947*48 • 76

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PagePowdlatlen of Johnson taw* Seed la Sogareaae HeldsI^Uov Hewed in 1947* 174$# **d 1949 m 19mentations la 13 ParieJsee 78

Seed ItajaOattens of Johnson taw* in Hfesied StubKle Sane tea* IS Plantation* in 9 Papisbe* • « ....... SOOaapiretl** M » n of Seed of Johnson taw* ii there tam end1'Bean*' W**e Planted in 1947 and in Held* wicii were Pane* f«ovm m */4»j *ro in wnxan me seenwteenNn vwiAssdniliril ps*'jjj*a.wa**npwen w 4* d d 9i n * * a a w m * *■ at, ■* *» &

of the Population of Jefonaon tiw*ii Seed in Meated* Bfcubhle# Hillm Plowed Fielda whieh had b8«a Planted to dean end Bean* ewM Sutoffian Pallo*ITirrud to SttMrtr* fih±iitt&«Mft. ; . » * . * « » * * * * * * » SB■eaii*eswwe* eaP Bt aaMPw * wweeiiMwewnMMmr ® t* • w w 9 * m a e* ® a * 9 wffrifdwel l%n*Sntlen of Jofaneon Grass Seed in AugustBUrtt Cans cl Two tooctionc Illlei V&enaA In 1949JUPtow S««d 8d of May, 1949 tin J&owcd Under . . . . . 9*

Johnson Ones* Seed Popnlatlon in Plant Sane Held*After Fallow Hewing $ e taitfop Ifctoate* PtHotdngO -iai n#inny in 194$* Subjeot toOnXtlwatlen thereafter * « * * * * ♦ * « • » * * • » * 84Population of Johnson Grass Seed In the Soil at Two Leeatlons fallow Plowed In 1947 dnd Followed bp Hand Bogoeing of Plant Cane in 194S • * » * • , « • S5Siweep of Sugarcane Helde few Johnson Gres* Seed ledged3Between the Leaf Sheath and Sane Stalk* • • • * 87Gemination of Johnson Grass Seed Beeovered Betweenthe Leaf Sheaths end Stalk of Sugarcane. • • * • * « * SBFrequency *f location and Total Itaber of Seed Lodged Between the Sheath* and Stalk of Sugarcane, hp Nod** * SB

4MbSW3L

ABSTRACT

la recent years the moat serious weed pest in the sugar* cam areas of Louisiana Las been Johnson grass* Sorghum h&lenenffi

a perennial. Until 19-47, relnfestatloa of Johnson grass in plant cane fialds mn sssucied to fee dm to failure to destroy rhisanoe during lot© summer fallow plowing* but in this year evidence was presented that seedlings were an Important source of infestation. Information leading to a batter under* standing of germination of the seed* the production of seed* and the distribution of seed in the soil were raeogaiaed as of value in the development of improved practices for the control of this weed pest*

Results of these studies indicated that a period of initial dormancy was present for several weeks in freshly harvested seed# After the passage of initial dormancy* seeds with the glumes re- moved geminated 50-70 per cent better than seeds frora which the £Lmee wore not removed. A secondary dormancy associated with the presence of the glumes was indicated*

Seed in secondary dormancy germinated best under conditions of alternating temperatures of 15°C,-36°C. Of Several materials used in presoaking treatments* thiourea used in a 2 per cent solution for 12 hours previous to germination at alternating temperatures both accelerated and increased the percentage germination of the seed#

vii

Seed ©ollacted from sugarcane areas of Louisiana and planted In the doll soon after hardest germinated bettor tom the seed with the glumes not removed which were geminated to the laboratory, (termination at this time varied with the years in which the seed were collected# bat the average was twentyw oigfat per cent.

Johnson grass clones collected in the sugarcane areas of Louisiana were foimd to vary in their ability to self* pollinate. The donee In which tor© was little or no self* pollination were capable of producing seed when grown tender conditions of open pollination, On to basis of differences in the ability to produce seed under conditions of self* pollination to presence of several strain© of Johnson grass in Louisiana was indicated.

Seed in weighed samples of soil from sugarcane fields were geminated, and duplicate samples of soil were sifted and tins recovered seed geminated* The distribution in to soil was found to be related to the cultural practices in to oultiva* tica of sugarcane. After late summer fallow plowing to remove rhizomes the seed were well distributed in to soil to a depth of 12 inches* Over 1.600.000 per acre were recovered froa in* fesfced stubble cane fields* The average number in land fallow plowed was 66.000 per acre, though tore were considerably more

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in IMtgtaM,Harrington and Oroofce* (13) described the Johnson grass seed

as a oaiyopsie and hyaline leans enclosed by two Indurated over­lapping glumes about 0*2 inches Xmg and ranging tmm straw to ■ almost W o k In odor* Two appendages, which ax© the pedicel of the sterile spikelet of the pal** and the rachis to the neaefc an­terior seed on the raoese, usually remain entire with the seed as it disarticulates I m tha open panicle at a w d M a f ined swtee, as described by Hillman (12), Qsklay (26), and Viaall (29)* The lower edges of the convex spear-shaped outer glume tightly overlap the aXi afcly inner 0mm whicli encloses the oviflL-ellipfcicaX browns ish caryopsis* The embay© of the caayopais la located under the prcsdmal or am? and of the keeled glume, Harringfcon (9) re- pelted that of tin gjiiaoe increased the germinationof Johnson grass seed when the after-xlpening period of several months had passed* The oaryopola coat or seed coat wee described (12) as the fused suberized inner Integument and the pericarp*The coat was found to he composed of eelluXse, £at-&a$xregnated suberin, pectie substances, oalolm, and iron, with tannins pre­sent in ail layers* Tbs Inner Integument sells were heavily thick** ened at the distal wad and thinnest over the ewbxyo* Even tba dormant oaryopees were shown to absorb water up to 50 per sent of their dry wsi^rt, and it m s suggested that the force of imbibition might not

be sufficient to overcome physical resistance of the coat* The pre­

sence of tannfns mA fat-lmpregnatod euberin in the caryopsls coat was

6

•a^ested as probably Halting the total amount of water absorbed, and the pezme&bilitgr to water and to substances in aqueous solttticm. Scarification of the caryopela coat over the embryo, own in freshly harvested seeds, ime Allowed t$r germination, (9) and this procedure was suggested as a viability teat for Johnson grass seeds, Oroclssr and co-workers (4) (5) have pointed out that the saturated embryo of S$SB JEBiSbySi l*a»»wi upon the unbroken seed cost with a fores of over 100 atmospheres without breaking 1% and that tt» breaking point of the coat and the growing poseurs of the enlarging embryo was important in tbs germination of nuts,

freshly matured seeds of Johnson grass m m reported by Herrings ton (9) to he incapable of germination without a four to five month, affcer-rlpening period, • One of the factor® thought to contribute to tba dormancy of seeds is restriction by the seed seat or m» easing ctruetures of free gaseous exchange (5), Harrington (10) stated that addition of oxygen had little effect on germination until a pressure of several atmospheres was reaoM under which tbs growth of seedlings was reduced, hut that carbon dioxide in** creased germination somewhat* Thornton (28) suggested that second* e3$r dottssncy, and possibly initial dormancy might be due to aocumulation of intermediate products which acted as inhibitors until a sufficient oxygen supply for normal oxidation activity and removal of the toxic Intermediates was achieved# Harrington and (bracks* (12) theorised that m bnMMbory mibstimoe held within the

wed seats might laflwmw Johnson grass wad germlnatloi, Ehloarea m» roporboft ShwpsoB and Koawr (25) as wMteetiro im breakiag donasnoy of lettnaa aeod« Xhagr also found (26) that sereral tide eoajpnmds <ffim than thiourea promoted the germlsatica of thesem4 » 0-93 M k m 4 dormancy $& latte© mmis % k M |tbe seed lift the dark In S5 .pm. of coumarin* fhe ImhlMtey effettfcof eouniarta was then owroisae % exposure to light and hl$k humidity*

te, light afte? teetemt ilth WQp to w&mU prnrnhm$m teatmenis, or in the M after exposure to thiourea. M bellevod it was quit® possible that ootcaaria, or its derivatives* or com* petes closely related t© it, wore the inhibiting footer in the germination of tea© seed* Barrington (10) reported that fee ©hernias!

forced ge3$$lnation of Johnson gras® seed, tut that nitratesiWI 6U*?06,y81«w8 lWpiw»8 uflfi gpria5 WSDaOB S JL3.w»*»* 4«6 4\3SOw<»a ulOl*of Seed Hmtfyets of North America have recommended the use of 0*2 par sent KSQ^ an a moistening agent in germination teste of these seedsJk«M| jMagMitet VfMfelMiSi w iP F ^V U i yp P w g

Barrington (9) (10) (11} pointed out the stimulating effect of alternating temperatures on the germinatlcaa of Johnson pass goads* ShUa the requireaonts of seed at different ages and from different sources varied, eoatanations of 30° 5°Gi, 25°-40°C.# and &Q°*;35°G., (the seed being exposed at the higher temperature from @*& hours) mere suggested* fho loner series are nos preferred* Caryopsee from

tosh the &vm* hm* 1mm * * m m & germinatea m m rtolly % 1 m oorreaptoSng #to# «i!h to gltnaes m both at «ltatnatlng temper* too# to at 2### fatoah&i ooastot totoatoes* Mmx&a (7) &otsd that all ssad within # sasgals do not havs tbs same tt j&ratwre

• 4%feiii& 'wlnii #>#■ rtifr #k%ok*wik#'ril'4hriiNkM# illdfriiittfli1*mu Si ill a*mstut a*1 Mk*»Mm.HimtkWarnJSfiSw#* XHOO wBH IM96U X03? 13#tttp0rot*\llrOB XOOQT DO CXOSSiy

a&SOOiStCHl with tfa# p9?0689fiMB8 Of Wttts# gSS ##l|SDjpi;|,- &XS&#pyl y iy ijgft# #0gg6St®fl by (3.)*

Soed l<ipYl,ity sbiallss may bo wM# with #t#MI ses# 0 IcaowaA-Mfk ASM Jb3ifehWHS A A M l nlmAto Sbttta A lt _ .SS A^iilltf **JLi jO bid'&£&> or wasy may do suaas By Duriaj. ox sow ••as# ## aaxxsroioij aspt-fts i& soil or sto* I# * tot of nto<ms wtos M toi(8) bnapied Jofoasc© gsiffH sosSft toads# Irrigated suS #i®tt#ii?rigatod so&dltl0KM3« Xbe ses$ g&ml&atod bstts# following burialtoads# iirigatsd conditionsj tha imagination at tbs *tv?. of y### being 81 per ««nt* at tbs to of to ysars 4$ par tot* to at 'to to of six yo*w® 0*5 to tot*- ftoto (£7) stoisto floodod

^ thi Colorado river bey stoiB'fiiiiB sssd olaatod ii MO. beneath 12 iaAM ef water* iftor fifty daye «( Butoergenea, Jetnaea grass m i d m Mill sapable ef 23 p»» eeut gennlBfttlai,

The technique for estl&atiai a t wed aaed popa*t4ona hr gemination at wed In weighed noil eenpilea and oowerBiea of toe amber of eeedlinga per eaajjO* to to* probata* 'malm a t aeed to toe aero we toteodueed bgr Bwnehley and toriagtoa (9). fhay f«md that eoan eaeda did ant gexm&wto iasaediatoly* but aoened to rebate a natural dormancy, m a unde* eendltlona favorable for gemtoatifiB#

noBXticfod aqq. aw» z*%bw3 «ann Os 04 ox ana atmaq pro azoa pa» 9$&at|* mssjuj *w paaofto; <m> «*»» laet® at& «$ «cr.vos&xI

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incapable of maintaining Ufa ton exposed to conditions favorable

to gerialmtlm* Non*viablo oaryopaea m m subject to decay organisms, ft»d failed to germinate when gently scarified over the emfesyo* With tb© glumes off* the first indication of normal g^rmimtion mo pom* tUHfifi ef t ho oaryopais coat by t o ctoorhisra, followed quickly by a loogitisiinal splitting of the seed coat over the oolaorhiBa along the area e w tho plrnmle, with prargpi appearance of the do* veleping emteyo* dll seeds germinating in this manner mre considered n&rml and counted* M abnormal splitting of to seed coat over to tftimxka mm ofban noted in soak or e3d seeds* If these mods did not develop roots toy m m not counted* With the #«ia©» <% the elongating oaLeoptile parted the glumes and became visible* fh@ primary reot sometimes pierced the gLmass, hot appearance at several ether point* m o osmtsm* When to eoleoptiXe m s visible between the glumes and sens evidence of root davblopment observed, to seed acre considered germinated* oonnted, and removed from to p&trl dishes*

In an attempt to find a material which moM increase the germination of Johnson grass seed from which to glumes had not been removed* 0elutions of several chemicals were used in presoaking treat* msnta* Seeds sere placed in test tubes and 30 ecu of to solution to be used fea? to treatment ms added to to tub®, to tubes agitated and placed in racks at 24ft3* for 12 hours* .After 12 hours t o co n te n t©

of each tube cere inverted into a 2» sieve, to solution drained off,

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m & rwwiiy tb* total jssab&r which had irain-sted in this period m s tmoiOsi* tmSt the soil m & stirred %® aismiaie, ct&iimUaa*

8®e£Li*ig& g»i&imt£l$$ late* meo recorded in a s$s&X©r isasmar,MsaX w rsts fm dM M a ll mdXfsgp mmtfbig two sHsntfos« f the data of planting,

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M a i tisJmtsUsR o f ssel adgfefe fee traceable to eloraX differano©

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amtem m tbs basis of the arm £m sMoh tbs rtoasm ms U rn#

b m m u 1*4 Jfeaarse, >9 ^sirXay* 10- 16 Soofcfc&am, 17*20 Oaffery,

2MS4 25*29 u ttis f m f 30-34 u &« o** 35*40$H& 'Ztfmmtom** 49-53 *teek«r# 54-41 S t. JMmis# 4 M 9 ^iemood*

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in Itoaiama* todi** m m initiated In to fall of 194? m topopulation of vlsUft Johnson grass seed In to soil In to major sugarcane areas © f t o otto, Seeds were recovered from weighed amounts of soil from samples t o m from various sugarcane field®In 194% t o corrected to t o number of probable seeds per acne# t o variation i n t o number of seed recovered waa an Indication of to value of this method as a erfeudy of t o distribution of Johnson grass seed In toss areas of Louisiana, ft was deemed necessary, however, to increase to number of samples t o m In each ftod during 1948 to 1949 for greater accuracy when t o pppulabiaa per asre was relatively lor. Samples of soil m m t o m from fields which had been fallow plowed throughout to asaeem, fields which had beau planted to som to beans to pleto to move rhisoaes before planting cane, to stubble fields which rare badly Infested with Johnson grass. Fields from 82 locations in 13 parishes in to Mississippi Hiver, Bed River*Beyeu Lafourche, Bayou feto, to Lafayette areas were sampled#& 1940 to 194% samples were not taken from to outer three rows alto to ditchbank, but were taken randomly fra to cane m m with* In to field, starting from to right of to field to proceeding diagonally to to rear to left# t o samples ware taken by members

20

«f the I*wiaiana State Agrlimltural Experiment Station staff ana the history of the field Iran which the samples were taken was recorded by tbsa m the do pound paper bags in which the soil was collected,

2h the greenhouse any clod* of soil were separated and each «m$Ui wee jtf#M through % mesh to the ineh hardware screen, fh® sell was walA tumbled to insure a uniform mixture, fhis was ©on** sidered a masts* sample, end frcm it one or more sub samples of 3,3 pounds was removed wad placed in one section of the partitioned flats and labelled* As the Johnson grass seedlings appeared they were counted and removed. After 3 and 6 weeks the soil was stirred to simulate cultivation, and the tests were continued for two months*A duplicate sub*sample from the master sample was sifted and washed throu i a 15-mesh copper screen, the refuse recovered and dried, and any Johnson grass seed present removed and counted. Th© seed were than tasted for viability in the laboratory.

Seed from samples collected in the fall was frequently dormant but viable after two months. 3h this case the viable aeed in the laboratory test was compared to the appearance of seedlings in the flats in the greenhouse. In the spring, germination in all teats approached 100 per cent, and germination in the sub-sample® was totaled and averaged to obtain the germination in each master sample, fhe germination in all samples taken from a single out or fieM was then totaled and averaged to obtain the average number of viable seed present per 3,3 petal sample and calculations were than made on a ©oau* paratlv® basis of an acre of soil Inches deep, The conversion figure

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v m wtfm of the degree of JotaMja gross lafeeia- tico i» the l m i&ieh the stalks more tafeeo, and were ftpfelloes* %Mfr-4Mtartatioo» 2-moderate infesiatlaa outer 12 feet, >h©«ur lofestotloo outer 12 foot, 4*®«^or«t©3^ heavy Infefftatlon thretigwsi, iHMttvy iafestetiGO throughout* €a»s stalks trm f&elde to tlse first three eategorles were out twm ths outer 12 feet, and £a eetegorlos 4 «®d $ from throughout the field*

studxjl:s m the € m m $ M x w or jghnscb? grass b b m

Laboratory tests in the early stages of this problem Maotsted of investigations ©£ tha optimum tempsrature ©eaaditicas available for gsrrainatioa testa, the extent of interferes® with germination by the glumes, the degree to which submergence in enter for w i w period® of tim would effeet germination, and the elimination of toads end ineffective chemicals In screening teste for chemicals possibly effective in stimulating germination.

To determine the response of Johnson grass caryopaes at different temperatures, the glims m m removed from seeds from time collections over 5 months old . The caryopses wars placed on filter paper moistened with distilled water in petri dishes which m m set in the controlled temperature cabinets, The S C*and 3J°C» cabinets were refrigerators, while the higher temperatures were maintained by automatic regulators in cabinets which were heated by electric light globes. Table 1 records the percentage germination at the different constant temperatures, A temperature of 1S°0, was below the minimum for germination. Appreciable gemination occurred at 24®$., but it was not possible to keep a cabinet in use at this temperature for subsequent tests. While the percentage of germirntlon Increased with Increasing temperatures, not all oaryopses in a collection or in different collection® wore equally affected by exposure to the

24

U tmsmtem of Johmm with the0 m m xomcrna fcieukatea at emmra! constant temperatures for 7 days*

temperate® fe* oont germiaaitcm

8 46 0*0 0,0 «»W 0.0 0,0 0,0H 75 to 58,0 to27 ei 73,0 73.0 74*030 06 79.0 33.036 97 84,0 79,0 94*0

Tsfc&s IX. Percentage germinatim ef .TeJmsan grass seed with the gXxEK>& m laoubaiied at stswral e s M waft altermtSng tss esatura* for 10 days*

te^ratiEse temperature Per cent i rminaticmto 09 Hemto toJ*..... teat 1 ...fact.8.. ...... .....25 m 0,0 0.015-27 8 59-81 to 6.015-27 16 59-81 to 10.515-27 24 59-81 m 21.027 81 5*0 7.330 86 19*0 20.015-36 18 59-97 22*0 18,015-36 16 59-97 32.5 39.515-36 24 59-97 to' 32.536 97 20,0 32.027-36 8 81-97 to 24.527-36 16 81-97 to 38,5

Refers' to the nitmber of hours at the higher t@mp©ratiu?e In th$ alterations*

*Sm» higher teapentaaw* SB toe m m pnOMa of tine. E m eeed oaHeefctaoa S to 8 mntoa old emtrltarted to repUoattana of teste of toe neejxma* of Johnem graaa owed with the glwwsa on at several tempwwtorea, tart no s&xtoswa of aaad were used witoto a aeries.£a tattle XT. toe raaulta «f toe tests of toe germination of seed at several eeoataot and alternating temperature# are recorded, - Ba toe altoamartsiona, toe testa wars began with exposure to tbs id.gmv temperature first. He seed germination at 15°0. tod germination was las at 27 6. exeept tosn seed were exposed to 3jSS. wmnjf ether day. fisradastieJB was totter, tart variable whan toe awed were exposed at 3tfl0. and oomMnationa InoXtoing

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13s®* fer B hsaam prmM*& tbs best oondittcms im most, eee&Xota end couM be tussd for 31 days a* losagar withorub araXd appearing m the filter paper*

Xa T a b le US *» W e d so®© of tbs msofeaftiemX methods employed to Xocaliss tbs point *t nMeh dormancy has been broken in r©latl*m to tbs xestriotic® by tbs glumes, end sbstbar or not tbs tomanoy W88 associated with the arabryo os? the oaryopsis coat* Stas first series indicated that with tbs glumea rsmcfircd, *mt ttai# U n IB tbs petri dishes ith tbs naked eaxyopsls, gsrmimtim m s pmag&* SoarXeieati0& of tbs glumes at the distal end increased tbs ieimina** ticn by 23 per mat over the cheek* la tbs second aeries of testa

26

Table Modifications e£ gemination psreesisgss by various meehanicaX treatment* of the glums® and oa*yopa©e.

Treatment ifo. N$* ft* om%wm^» days gemisatieii

treated germinated

« (Check) *30 «, 4*4Abates scarified 100 21 27*0Sbmft# removed 100 21 93*0Glumes removed andleft in |»t$& dish 300 %L 83*0

£ as (Gheck) 2$ 3 48*0glumes 25 3 100*0Glmes removed andeabiyo ©orered p&rrnm 25 3 100*0V

ffgffisg It a on (Oheok) 30 10 30*3(Slisnes removed :'j# 10 32*0<$1151068 os eNI 1, Needle pfonoture

above suture 10 10 20*02* Caryopsia removed,

returned to position 10 10 10*03* Gsiy^als removed

reversed is Isrea 10 30 5Q*04. Appendages removed 10 10 30*05* Suture pared this 10 10 20*06* Window out is glume*

over embryo and 10 10 80*07* CapHlsassr tub® pat bebrees glumes and

seed supported outof water 10 10 30*0

,___ „ vfcan barreefcsd)Glumes on 50 3 0 *0G lm e * removed 50 3 U*QGlumes removed m& rt(1* Unfeaye erelsed 30 3 94*02* Distal end removed 30 3 50*C>3* Back of oaryopal® ewt 30 3 88.0

SSSSS-SSSQS

fabl© I?, of grass seed during s t e ^ w i towater and af alternating temperature© in germtoators thereafter*lifr w mi wm w 1 * I I I im wnwimniiiiKiii I»n mu 11,1 mimmrni ,,»m .m wMwwp ., «.,r .. i.,,»

frtotont #o. Bead Iteration $ gona, $ gem*touted of stoerged 14 dap*

, .„ . „ ^ w . lll^ . , l, l l l ,., — .... m u m m m . Msau.m xm s m (took) 400 0 hours * 15*0i&SBto removed (Cheek) 200 0 hour© » 90,0geaM dlfffclHed wafts* 400 12 hours 0*0 14,5Soaked distilled water 400 IB houra 0.0 3*0Soaked distilled waft** 400 60 h e m 0.0 1,0Soaked distilled water 400 5 days 0,0 1,0Qnygen through water 3,600 3 day* 0,0 1,8Oxygen through water 1,000 6 days 0,0 1,2

hours apparently' Ml little effect an subsequent gemination, Thma was a pronounced drop la the percentage of seed which would germinate if they were soaked as long as 18 hours, sod when submerged for % days or longer, whether or not oxygen was bubbled through the water, germination averaged slightly over 1 per cent. When seed soakaa IB hours were bleached with the glttaes left oa, us tog se&te hypochlorite 5i per cast (COoross:), it was found that the bleaohtog occurred at both the distal and pem&ml ends of the eaxyepeia and glumes, with a belt of unbleached cost remaining to the center of the ©aryopsis, to illuetratitm of this may be men to Figure 1,

£h© point of rupture af the caryopsi® ©oat at the tie© of gormtos* tion of 300 seed of a&a»d ages with the gtopss removed was over the tip of the ooleorhissa in 91.0 per cent of the seed, and over to plumule to the remaining 9,0 per «wt* When rupture of to oaryopsi* occurred over to plumule, to radicle did not always develop, to Figure 2 w be seen to imbibed oaryopsis, to rupfeur® of to oaryopei©

m

seat *m* the eelaerh&s* Otomfo 20 minutes after it became visible* wad tbe further spotting of the osxyopsis oost as the plumula develops sfsiashat later*

la an attempt to find a mtsrlal oapabl© of inoreasteg the germination of Johnson grass seeds with the glumes on* a number of materiala sere tested* Sating these m m the lipoid solvents ethyl ether, sylol* 93 per sent alcohol* and several spreaders m surface tension breakerst M M UM&I, triton xlOD, i>?ytrm# and bn Font epr©ader*stiofcer « bone of these proved useful in the laboratory or when added to the water used on seeds planted in soil in flats in the teahouse #

A iasato of $ttsrganlo and organic materials w o tooted fm toiy ability to increase germination of seeds from which th© glass* W not removed* $J» degree to which to chemical© inatttoed gemination was measured by to percentage gemination at to 10 day pasdsd* to ty acceleration of germination in 4 days, fable V re~ cords to percentage germination of Jotan gras# seed which had passed t o period of initial domanoy ton treated with several chemicals. to tor duplicated testa were all toe using a m m meto&l seed lot from Louisiana, in which to viability was apprexinfctely 50 per cent* Instruction of seeds tom which to gtmee mem removed by molds m bacteria within to ten day period was t o considered criterion for lack of viability in to seed lot*A number of materials increased to gemination appreciably in one or more of to tests* fhese wares thiourea* potassium nitrate* laetic acid, Jbwad #23* manganese sulphate* sodium aeparinginate* tannic sold* and potassium thiocyanate. Since neither tannic acid negp a hot water extract containing tannins reduced germination* these materials as such are probably not active agents in preventing germination of Johnson grass seeds* M fable ?I to materials which were fctad to increase to germination of Johnson grass seed in a ten day period are listed with to per cent germination after 4 days*

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fS&UVX, Germinatian pareentagea of Johnson grass s®ed 4 days after treatment with certain chemicals for 12 hours.

Treabaent fast2

Test2

Test3

TestA

M m m

( H u m removed 44 #0 36.0 46.0 43.0 43*$(Banes on (Water teak} 27,0 13.0 10.5 10,5 If ,32 $ Thiourea 3 M 13.0 32.5 33.0 30,1$ £ Potassism nitrate 28.0 10.0 ** 23.0 20,32 $ Lagtfo aald 32,0 22.0 13.0 16.5 20.11 £ hasad j&| 29.0 5.0 21.0 22.0 19,32 i itomtawiatt SulLrihate 33*0 17.0 M 11.0 20,32 £ Sodlias asparingfnat© — 9.5 26.5 13.5 1^.32 jl Tannic acid e 22.9 20.5 17*0 30,02 £ Potassium thiooyabate 25.0 *»

vsBBmmtiae«. 34.5 18,0

The outstanding chemical in acceleration of germination m% thiourea, if three categories be considered as the basis for judging the effective- m$s of the chemicalsf reliability, acceleration of germination, and total garainaticm, thiourea rated first In all tee® categories, tea of tb* other eheazdoals was mush superior to pe&assta a&tfcst© which, in a 0,2 seat solution, is used to roister the substrat© in germlnaticm tests of Johnson grass seed &s s®M testing laboratories. However, additional tests sere made using fcajsad 0$ in solutions of 1-500, 1*750, and 1-1000 dilution to moisten the filter paper la petrl dishes, Seed which germinated 9® per ®©«t with th© glumes re­moved, and freshly harvested dormant seed were used. Tabls 711 records the percentage germination*

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AA

34

fable iftXt mssm&m* tbs effect of tbs addition of a smallquantity sf bcCL to sasde in pet*i dishes with distilled water, Kaoh of to tost* yam made m a single but different scad lot*

f*Ms TOP:* Percentage gnmiavbtai of Johnson grass seed with a smell <suantity of sod ttm 9 areas added to distilled water in p*txi dishes*

tot 1 tot 2 Test 3 Bey c«at29 seeds 25 seeds 25 seeds gsrmiatffciouSo. Bo.

AyoragB ofper per Bo. per l'oatasoil cent soil wswm soil centsamt&e eeim. saamLe srerm. aamiale ssrm*

Bed M t®? n r 24.0 % 10.4 1 15.5g<aetn^y«|, |L 3 50.7 1 12.0 1 40.0 37.2Bayrn Lafourche 4 di*o 1 17.6 1 32.0 , 36.9Bayou Teobe i 56.0 1 10.4 i 32.0 26,1Lafayette i 54.0 1 13.6 i 24.0 31.2

Total andAverage 10 51.1 f 12.9 3 24.0 29.3Gheek(Distilled Water )1 52.0 5 12.0 1 32.0 32.3

The result® csdt these tsets indicated an inhibitory effect of the BodBiver soil frca& Hooka? plantation on germination of seed. Sine® it was possible that a difference in the noil® could contribute to a difference in the germination of Johnson grass seeds m & partially eae» fimtn difference in reinf©station, two seed lot® were germinated in soils fro® five areas in 1947. Bemalb® are given in Tabl® IX. tore was little difference la the average gemination percentages in soil®

fwm Saar of the tmm «. ta tin Untonie soil used os a aheek,la the Red River soils*

TatOa Wk Bmmimtim of 2 collootloas of Johnson grass sesd la avSM & m IB plantations la 13 parishes la the fail of 19.47*j}gcfe'$'wtU& "' lhamber of " J^^oent ©asniaation '

Sellsctsd plantations la seed lot frcwt .,.,--- Suoa Jtesm....Mt£a£L , f Jkmpmm.

Miaslftslpspi H a t 5-4 55*7 16*0 35*9Baswa IsS&urofce 6— 2 61.4. 16*9 39.2Ss^sa Teoha 3— 3 57.9 17.2 37.6Lafayette 2— 4 50.0 22*0 40*6

ferfl, 314 ilo 16I2totals and Averages W 15!& 15*6 34i!>Lintc&ia eoH (£heo&) 1 70.5 0.0 39.3— 1 St* Lelpfcira, $t. loala. iteGall, Raaem, La* Agrl. Bap, Sta.— 2 Paincoustvilla, Glsnwood, Madewood, Little Tsana, Greenwood, Southdown — 3 Sterling. Albania. Paanga Preve — 4 Slllesai, YouagsvUla — 5 lieelwr. Shirley

Three soils ware selected for further investigations* These nest Lintoaia silt loam, Mississippi alluvial silt loam, and Bed River fine*m& silt loam. Implicated germination teats ware made using two seed collections eaoh year In these soils collected in the fall of 1940 and 1949. The results are recorded in Table X* The seed used wore from late mm&v collection* of the eurrsnt years, and the tests lasted through two months each.

36

fa&L© X* Gemination of $*$mm grass seed in three soils in the fall of 1948 ana ©t imt.

Sod# Source mid per ©eat germination of seeds AverageCollected 3$4fi 1949

l*tefeca4a 50,0 40,0(silt loon)ESississlj jiallwiel 44.O 34.?(silt ©lay loam)

Jted IHver 34*0 50,0(ffae gilt loam) .T&sOTgw ^5^ «3T

Brorgrepai19.3 €1.0 42,6

18.3 73.6 42,711.0 6,0 17,8B y W ) B3f

The gemination of seed from all four collection© was 1mm? ia the Red River soil than in the Lintor&a and Mississippi alluvial soil, though the average germination of tine seeds in the four collections ranged from 16,2 to 46,9, fst&e XI presents a summary compiled frcm the gemination of 2 seed collections each year in soil from the three areas in 1947, 1943# and 1949, As may ha seen in tho gamu&y* germination

laKLe XI* Summary of 3 tests of effect of soils on gemination*

Sail 1947 ,. Tea, 1l'teTwafc 2 1949T«a, 3... .,.-.AsatfiM---- -

trintenla soil 39.3 45.0 40 .1 41.5Mississippi River soil 35.9 39.4 45.9 40.4M l River soilAmmmmsverBges

1&-2 27.031.5

17.233.0

17

of seed in the Sted River soil was eautidmlOsr lower all time yeara than germination In tbs Untonia soil and the Mississippi alluvial soil* m explanation of this prohlam of Inhibition of genriination of Johns**. grass wads % Bod Hirer soil was attempted.

ffca addition of fresh can© Shaath trash to Lintonia soli, at ths rata of 800 grams cans trash to 10 kilograms of soil resulted In the germination of 47.0 per cant of the seed In the treated soil in two months as compared to a gemination of 57.0 per mut In the untreated check.

3n oidor to obtain some information cm the depth from which seed would geminate in freshly cultivated soil, 200 seeds were planted at depths of 1, 2, 3, 4s 5, and 6 inches in sifted Idntmia soil under conditions favorable for gemination, fable XII records the appearance of seedlings above ground in two tests after three weeks. 2b© soil temperature at 4* in the first tost reached 34%. m the fourth, fifth, and sixth days after planting. The temperature at this depth was 3S C9 the third am fourth days of the second test*2n the second test, Ida© seed were watered eft each depth as they were planted. Xh both tests daily watering reduced the actual depth of the soil in the built up flats over *J- inch in $ days*

Table XXX. Johnson grass seedlings appearing above ground fraaiffegBKt Test no. ftUgftfoy, tofl&if, .

% seedlings appearing above ground fra plantingdepths Of 1X« 2fl 3» A* 5*» A«

m.#2Averages

33.0 1 29.5 51.0 r 86.0 5.5 0.0 55-0 6oIo 594 39.5, SfyA

H3> W 3 554 P 4 S O 10.3

m

Indication* m r* that < w 50 per cant of the seedlings m m oapa&te of appearsno* tk&m ground when planted at a depth of $ inches,

Hi October, $$47, a teet was started to date mine the germing** tld& of two collections of Johnson grass seed after huriaX in taa«* cultivated Hiesisflippt alluvial soil at 3, 6, and 10 Inches after e^h of five years, the seed collected In Sepftember, 1947* from Albania plantation geminated 57,0 per sent and from Baservs plantar ticn 54*6 per cent at the tia# of burial, Both bronae and plastic screen cages m m used as containers fear the seed to he recovered at the end of the first two years and the geminaticm percentages are rooorded separately in fable XXXI. At the end of one year of burial, gejsaioaticn of seed in all the metal screen cages was slightly lower than in the plastic cages, but the difference was not noticeaMa the second year. Germination at the 3" level was lower both years than at the tins of burial, Some seed were found to have germinated without any seedlings becoming established, The seed buried at tbs 6n and 30* levels geminated about the asm at the end of one year as at the time of burial, but at the end of the second year the germination of seed buried at these levels ws© greater tirtn at tbs time of burial, or one year after burial,

The germination of two lots of seed which had been soafead in water an 1,000 ppn. sodium salt of 2,4 ® for 60 hours was less than 3 per cent in both eases, though the seed soslaed in 2,4**® produced

39

mi*burial In tbs soli

io» of Johnson groom seed after

Sil'^iatopatc«y G&xws esed each ffccm

Bar esat germltiatlcxdt after 1 sear

genalnatlow2MI«Hi.

broom eggedI* 16,0 12.0Uliairf* 1* 30*0 60.010* 34,0 04.0Baser** 3* 40,0 46.0Bsserve 6» S M 30.0B*se?ro IP* 64.0 ao.o§ & m » ch-400 seed each fvm

J M 9 gage*3* 7.0 3,0i1W<| d» 51.062.0 79,0Albania 10* 77,0Bsssree 3*d« 12,0 55,0Iteserve 69.0

67.000.0SfSITVi 10* 87,0Qesalafitlcn In soil»

500 seed eaeh3* Brens* 5*0 00,6f* Jlasti* 33.4 15*8

AThaMfi 6" Branae 6* Plastic

44.268.2 69,058.8

Albania 10* Bronae 51.6 85,0Mbsdtt 10" Plastic 61.6 61,0Bosses* 3* Sronaa 3 M 48.645.6Baser?* 3* Hasti* 57.0Reeerw 6» Brens* 54*0 69.2tBsfcSUfeflSMMlK'IVWA1 W 6* Plastic 73,0 99.4Reserve 10* Broas* 59.6 71.0Reserve 10* HaeO* 9 M 91,6

f «g V Qdxsoinatlm in Lab.(50 seeds each) 8.0Air stored m

flH N vW Air stored 155.3 44.0Total* and A*s*m m In soli 19.2 8.2AThaitrf* 3*

pft\*LK*A d» 36.2 63,9flglwwftifi 10* S6«6 73.5Reserve 3* 47.7 47.1Reserve 6* 63.5 84.3Iw lW l’VS 10* 75.9 81.3

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■Me

Treatnssnrfe In test gamiaatedt

fllpffiUJjjft QJIBurled seel

100 24 24.0*Shook inGlvms serna-redl 10 10 100.0(HtBSOB GBL S5& 297 84.9100 p m ZJptoG&ams rmxmb. 10 10 100.0COmes cm 350 237 67.7**1,000 ppa 2*4*® Glmss xemm& 10 9 90.0**Gl-anes cen 350 ____ ____194 ________ dr*; / mjui

* Bern; inhiMtioB of •: I 1 0 ~ seedlingsabout 10$ 0®soeotyl0 ti&ek, ***Ho normal recta or aesocotyln.

ffcrafw ft'M jsti o f suiuaWlan o f Jn*martfi g rass Bead fafrmvHm bCmVMBSSIWSnBbBpP 4PHw 4VBPViPlWiWVV *W®BMppp

The germination of eamplaa of Johnson grass seed fra oolleeticma made in Umisisna during 1947, 1948, and 1949 marled greatly, "oat seed fra all collections were capable of geminaticm. Tahlo IV records the percentage gemination of 30 Bead collections tgm 6 areas in the *nn of 1947 *hea planted in the soil and wten geradnsted in the laboratory in Petri dishes two meaka after edllectian. The germination m e 36.6 per ocat in the soil a# eta- pared to 10.2 par cent in mater in the laboratory.

When these seed collections mere 3b months old the glumes w»ra renewed fra 2400 seed in order to compare the gemination of seed so treated mith an equal number of seed fra mbich the glumes mere not removed. The gemination percentages at three different time intervals are indicated in Figure 3, After three days the gemina­tion of seed math the glumes removed m s 74.5 per eentj after 7 days

it m s 82*8 per cent; after 18 dayn it was 95*8 per cant* With the glasfte left <% the germination at the and of 3 days ms 11*0 par osntj after 7 dare it u s 18*7 p& cant) and after 18 days it m $ 24*4 par cent* A photograph of scad from three collections, those from Southdown* MAleaud, and Meeker* and illustrating th» mm&ts obtained when the glmes aero removed from the seed# ray be seen ia figure 4* U x m the seed# from which the had

bean removed germinated mpidlyv approaching a total gemination, of 98 per cant in 18 days, a dormancy associated with the gXmeii m s indicated.

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ferent ages in 194®* a period of initial damaney of about 12 soaks was Indicated*

Sb 1949 a comparison similar to tbs cm© of 1948 was made*■using information recorded in table OT undo* the heading **Qeiminatio(a tost for 1949"* A total of 85 seed lota* 63 of which rare tested for per cent germination she®, over 18 seeks old* and 22 of which sere tested when under 18 seeks old* contributed to the comparison shown in Figure 6* The average germination of Johnson grass seed which sera over 18 seeks old at the time of the test in 1949 saa 31*9 per cent sith the glumes on and 79*9 per cent sith the glnmes removed* From the results of the grains* tian of seeds sith the glumes on and sith the glumes removed In 1948 and in 1949* a secondary dormancy associated sith the glumes saw indicated*

The percentage germination of ten lots of air stored seed when planted in the soil sithin tso seeks after collection* m& at various periods up to and including 30*34 months* la given in Tabl© X7II. termination sas markedly increased from 12 to 18 months after collection, bat decreased appreciably after 24 months* Early in the third year after collection nearly 18 per cent of the air stored seed sere still capable of germinating and establishing seedlings. There sere pronounced differences in the ability of seed from the different collections which had been air stored together to geminate after nearly three years. Three lots of seed gave

f a&2© WXI* of air-stored seeds collected in 1947 and germinated in Xdntonia soil

Plantation and area ecllscbsd and data of

Age of seed at tost in

Be*cantgerm2 TftO*

Age of seed at teat In >««&«

■0B9Tcentgem

Age of med at test in

Pereentgsm

Age of seed at test in

Percentgem

Miagissiopi-I^camdwCinela^6/17 1 21.6 24 13*0 20 0.0 34 0,0Paincourt^lle 10/23 2 25.0 20 09.0 24 41.5 30 39.5Southdown 10/24 2 6.6 «. - 20 10.5 30 34.0TankaAlbania 8/6 1 13.0 12 33.5 26 17,5 33 5.5Albania 10/24 2 45.0 30 69.0 24 4.0 30 3.5LafssaMe Bllleaud 3/6 1 50.2 22 63.0 26 45.0 32 19.0BlXLeaud 10/24 2 28.0 20 ^ . 0 - *» 30 16,5

Ba™^ Hlqffi Bayou Black 10/23 2 51.0 20 92.0 - a* 30 3.5

J mSLIfeakSrS/U 1 19.0 22 50.0 26 30,5 32 27.0

Seeker 10/30 1 30.0 20 79.0 m m 30 28.5

Totals and averages 28.4 1 * 62,5 25 21.3 2L 17.7

52

higher germination in the final test than when plant©! m m aftercollection,

Blth four exceptions th© germination of seed from 110 collections planted in the soil shortly after ©enaction increased between the ecmnt of seedlings made three neck® after planting, and the final count made after two months* IMie the passage of Initial dormancy would partially account for this, there seemed to be sane difference in the response of the seed in the soil related to the area from which the seed was collected* The germination of the samples from the seed collections after three weeks, and after two months is recorded in fable OTIX* The percentage gemina* ticn of seed lots from the Mississippi Mirer and Lafourche areas averaged somewhat less during both periods in the sell each year than the average of seed lots from the Tech©, Bayou Black, la* fayeite, and Bed Hirer areas* The difference in total germination was also notable when the seed were planted after a period of air dry storage, though 40 of the 78 seed lots tested did not produce additional seedlings during the second period of gemination*

In order to determine whether there was a significant dif* ference in the ability of seed collected from different sources to geminate in the soil i&en planted com after collection, an analysis of variance was made, using the average f^mlnatian per* eentage after two periods in the soil in the first gemination test* Tho sources of the collections ware the Mississippi Rivor- fourche

S3

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Tatle Xfflll. (Continued)

Plantation o r M&L

GlenwoodL, S. U,L. S. U.McntegutBeserveSoutbdowfcSt. DolphinSt. DelphineWesternerWestoverTotals and averages

*9/49 . /49

11/m/m 6/30/497/20/496/1/498/6/49XLhzJifi6/30/496/30/49(>m/miafivmbfzifm11/13/49

6/30/496/30/49

6/30/49

ifeekor 7/20/49Shirley 7/20/49Totals and averages Accumulated total and averages

Mississippi Mver-Lafourche area Tech®, Bed Rlvor, Lafayette, and Bayou Black

SterlingLafayetteBilleaud

Age at Per cent Per cent Age at Per cent Per centplanting germ, after germ, after planting gem. after gem. afterJul weeks 3 T3©eks 2 mca. in weeks 3 weeks 2 HOE*3 8.0 11.02 3.0 15.0 Op - •

0 9*0 40.0 -w -

17 36.5 38.0 - - *

04 15*5 16.0 ft*

0 2*5 9.0 4* *•

12 8.0 6.5 m1 0.0 2.5 - •

17 26.5 27,0 -

12 7.0 10.0 aft- • •

17 8*5 12.0 •ft • aft

3 2.0 4*0 •ft a* •

17 7.0 12.0 w* «ta -

- D ________ - QUO 1*0 - •ft ■»

9*7 14.4 a* •»

17 22*0 22.0 •ft «ft

17 23.5 24,0 «»

17 8.0 8.0 “ *ft ft*

34 23.0 23.0 M

U 27.0 28*5 ft* • •ft

............._________________ .............2UL______ * « «•

14*722.824*632.6

42.660.9

43.464.7

c&ckm, aiBDiss cr jam m v m m w m m u m

Obsecrations of Johnson grass plants In different areas of Louisiana suggested that differential infestations of seed on tto various plantations might to ins to olenal differences in ability to set seed, perhaps toesuse of tbs presence or sfbsenoe of pollinating clones la etose eseoelstioB. table XEC mozde a count of assails florets with and without cavyopsto which was made of tea spas pollinated typical toads from tea elates differ tog to appeazwnoe and aeed production. these w s eolleeted at Ctodare plantation in October, 1947.

tatts XU* Coasts of Sessile florets for the deterntostion of the percentage sith nstnza eazyepeee.

ir*. «r *©• Of la. or la. ef Per sentClone Branshe* assails florets ef HorstsHe* to M flasets ijiw w«ryqp«Mi with Cazyopsee

1 ' ::f 25 313 87 77.0a i$ H 24 37.53 30 96 74 774.4 24 98 1® 81.55 19 137 93 67.96 29 892 38 13.07 15 489 4 0.8a 30 524 289 55.29 34 649 258 39.210 24 511 228 44.6

Averages 25.2 297.7 117.0 39.3

59

60

Swd productioi 1mm bo relationship to tbs else of tbs bead aor to tba mater of aaaalte flerate. tbe pw eont cf florets wtlsb eaxyagala mngad £»«■ tew tten em to eww eifb&y*«m* aith an «rv»mga « f thdatgMadw*

te eritar to atady tte pcOten and mod produsttoa and aMiitjr to self palteairta, tebnatm gnu ptects f m 38 teaatlana new collected from the eugawane producing a m i of Louisiana apt the clonal tgrpas were assembled at tfcc Louisiana &e*perineni Station In 1947* following the selection ©f 60 clones

tiiQss pdsflshsi "hftgatSxsif $# 194#* theoe were again space planted. together in 1949* F<ar&$n*nix» aim# liat 21 a m i Kloaasd In tia» fear stadias ef hath seed production and pollen i&aduatlon# One additional a i m an which detailed inf ©nautical of selling a* fcilitr had been collected in 194&, produced fcLocans in tdbaa fan studies of pollen production the third week lha August. Table K promts in detail for 50 ©lonea the production of pollen* based on tie number of paHaa to the lav peror field of tbs miarm^pi* fhe mndieg of low power fields stated is the total number of aathefs of the oasmiaedf tut it is not the actual Count of the number of pollen grains produced tor that anther* Freeattfcions were talcen to assure that the field chosen for counting was ropreseniative of total anther production, however* Xa interpretation of the par cent of fall pollen, any percentage over 90 la camsily interpretated as noraal, and empty pollen present due to other than genetic causes*

Differences ia both anoimt ana size of pollan grains were- not&d. For example, In e l m amber 2 there wore two sizes of poUen seen# both of which ware foil of eyioplasa§ in clone number 26, two sizes of pollen ware aeon only the larger of which was full of oytoplasiBj in e l m number 84, two sizes of pollen were seen both of which could be either mature or defbotivej in clone number 86, only the smaller pollen were seen, and this was largely defective $ and in e&ene number 14, only the larger sine pollen was seen and this was fbll of cytoplasm. Two clones, numbers 30 and 127, were found to hot* abortive pdlen sees arid produced no pdli®. locations were that pollan production was a dossal characteristic, and that ir» regular aaioeie occurred in m y donas.

& order to study the difference in seed production of lo&son grass dosses, the number of seed produced per head under eomdltlona of open pollination and self pollination m m compared* fhe number of seed produced, the degree of coifing in per cent, anti the average amount of pollen produced is given in fable HI*Ttese results include the Information obtained from studies mads am 49 clones in 1948 and 1949, with 7 additional clones on which data were assembled in 1948. Of the 17 clones in which self pollination did not take place, two clones, numbers 30 and 127, were found to have abortive pollen sacs and produced no poUeaj five clones, numbers 36, 53, 79, 97 and 129, were found to have @&» tremely dark, small atlgtnaa, a factor or combination of factors possibly linked with selection against their own pollen, since open

62

Tatle XX* Pollen Production of 50 clones of Johnson Orass in 1949 at fiatca Rouge, La*

Cion* No* of Average pollen Per ocs®Ho* pollen mt count matuMcounts Mature Defective paaaaa

a 6 § 16 7742 12 136 3 97,86 12 14 37 2747 6 120 6 95.28 6 69 13 86.213 6 $6 7 88*8■14 16 64 10 36.516 6 a 3 94417 6 18 18 30.021 6 131 19 87.323 6 17 29 36.928 6 41 19 68.530 24 0 0 0.032 6 47 3 94.035 6 129 5 96.236 6 56 4 93.537 12 23 17 57,544 6 116 7 94448 6 36 40 47449 12 56 7 88.8a 12 53 23 69.753 6 37 19 66455 12 127 5 96.156 6 48 4 98.359 12 17 39 30.461 6 74 9 88.864 6 43 2D 68.366 6 145 7 95*467 6 57 7 89.071 6 108 4 96*475 18 42 8 84.078 12 41 10 80479 6 19 m 47.581 6 20 17 54.08486

624

478

131678.318.2

90 6 2| 1 88.593 6 50 3

IS94.3

97 36 19 55,998 6 56 6 90.3IflQL 12 22 16 57.9

wmmMMMMw

XX. <0«itiB&adl)

63

Clcfi«No.

No, of pollen ooant*

Average pollen per eotmt

Mature Defectivem&turepdllali

102 6 ? 63 10.0107 4 m 2 90.4103 6 105 33L 90.5no 90 6 29 17.1119 6 29 4 37.9123 40 M 54.5125 6 5 45 10.0127 24 0 0 0.0129 12 29 U 67.4

BaCTjatiiaBLaj." gaBftWHigflMlfc

totals ft Are,

Totals ft ft*.

64

Ta&Le EEC, Results of Self and Opoa Pollination of Johnson Grass frcB Sucsraena Anas of touislaaa dosing 1948 andSo, of Total "Sffi'”-'""" Segrii Ave, iio.clone* jjoH Ib** no. pollin­ of mture

*fc±«n ation <ta*T ffit a* poHesaAre* no. bagged An. no. per eamtaoed per cent

. nor heed6 345 ”5 0 .. rr-yn. ,™tfrsn.r-nin »r„™.a30 288 6 0 0 036 144 3 0 0 5037 287 6 0 0 2351 170 5 0 0 5353 547 6 0 0 377? 238 3 0 0 1906 294 3 0 0 08797 &

311

00

00

m19

102 322 3 9 0 ?HO 20S 5 0 0 6in 37 3 0 0 aft112 295 3 0 0 *»125 59 3 0 0 5127 197 4 0 0 0129 .... 3 _____

17 267 73 0 0 2©

5 588 3 6 1,07 762 3 9 1*28 534 3 4 0.8 89

16 478 4 IB 3.7 5117 446 3 1 0.7 3823 302 4 13 4.9 1728 262 3 3 1.159 170 5 2 1.2 1771 278 5 5 1.8 10875 456 4 7 1.5 4278 459 8 3$ 3.9 4184 215 3 3 1.3 4793 223, 3 7 3.2 2308_____ 294_______ 3 7 ..............2.4.... 56.

14 390 54 7.6 2.0 45

65

Totals & Are.

Totals & Ave.

Table XXI* (Continued)Ho. of Open "Total Self Degree Avo* No.does pollin­ no pollin­ of mature

ation heads ation selfing pollenAve* No* bagged Ave. No. in per countseed seed per centner head - dmt. head

2 5 60 9*8 13213 372 3 113 30.4 5620 103 4 27 25*0 m26 280 6 18 6.3 4132 388 7 126 26.3 4744 272 7 57 20.0 ll640 206 6 126 61.2 3649. 190 5 102 53.7 5655 390 4 27 6.9 12756 403 6 84 20.8 4861 223 5 26 11.6 7464 535 2 125 23.5 4367 298 4 38 12.7 5790 221 3 13 7.3 23i d 730 4 39 30.0 22107 288 2 46 15.9 136103 87 3 9 10.3 105119 331 3 147 44.0 29£1 _ H5 3 _ ... 21 ... . -..5.9

19 295 82 64 21.0 65

1 357 4 357 100.0 5434 4831 5 514 100.0 6421 68 4 66 93.9 13135 476 3 459 96.4 12966 193 4 225 100.0 145123 19A L 201 _ .100*0 ... .- 40 ..... n .

6 295 24 304 100.0 94

paUinattan 4ld oe«a*} and five, clones numbers 6, 86, 208,210, ana 125, « m fewd tc produce less than 30 j®r cent nature pollen, the overage number of nature poUec grains produced t®r the 27 clones in ntdeh self pcOlinetion did nob tabs plane ms 20, tgr the 14 clcnes in which 8 per cent meg® age self pollination took plaoe was 45, by the 19 clones in vfcloh 22 per cent overage eelf pollination took pOaee vats 65, and by the 6 denes In ahich 200 par cent self pollination took plaoe was 94.

8 w * is presented in 7afcl* XXH a oaaparlsen of seed sat tmden coaditicna of open and self pdUiostica baaed on data ob» tained during 2948 and 2949 tram 27 Johnson grass clones in the four general classes according to selfing ability,

table 2SZZ, Gmpasisoa of seed production by Johnson grass clones sham self pollinated and when opon pollinated*1 ■>■■ i» m asm«ammewmmwem^iismiisaaamaeiaMaiiaiiissaaewmmioa4aawiasmmeb»nillMlaeaa>wt|#iiaimda*^^

Are# degre® So. of On io£ eelfing oldMt So# 1raii|^ AW# }|0# 0Wdi S6# Aw *in pe* cent heads psr head bagged mmi

0 5 10 350 2? 01 3 12 352 2o 1529 A 3 384 20 u i100 2 4 419 9 443

Of the five clones which produced m eeed when self pollinated#one had abortive pollen sacs# two produced scanty pollan, and two

67

had e reiaely dark, email stigma## Seed production off el<m& fvm. the clasa which self pollinated 1*2 per cent f^qumtly produced no *eeed when bagged* but in two casea about 50 seed wet® produced# tn the Class which averaged 29 per cent* pro­duction off mod frequently differed widely when begged at different tines, while in the class whieh self pollinated 100 per cent, production was consistently high*

dan&l differences In activity off the stamlnate pediciXUte spikelet were noted# Bpikelet# of clones nuaber 6, 5?* 79* SI*97, and 125 were almost entirely neuter or abortive# Occasional­ly p d U m was produced* but asnthssls and dehiscenoe of tin stand*- ate spikelet was faulty. This was true of clones number 4$, 49, 75* and 86* Clones number 2, 7* 8, 14, 52* 66, 95* and 96 were cte&eiejv ized by pronounced anthesis and dehiscence and the full pollen produced by these clones was ever 67 per cent#

Three samples of ID seed each were selected at random in 1946 and In 1949 frcm a typical head fTcea eight clones of different types and war© weighed# 3h order to check to reliability of to sample an estimated weight of to seed lot was obtained and compared to to actual weight# Table XXIU tows comparison off these two weights*

68

Table XXIII, Comparison of actual and estimated weights of seed Troa 8 clones in 1948*

Cloneno. No. seed

to headActual weight in ar-

Estimatedweight

. ... in er,._....Per oent accuracy

2 630 2.435 2.462 98.8978 450 2.474 2.430 98.1230 354 1.761 1.894 92.45119 290 1.410 1.560 88.7397 495 2.366 2.309 97.5914 380 2.670 2.649 99.226 565 1*854 1.876 98.81110 226 0*731 0.747 97.80

Totals 3410 15.701 15.927 98.56

The total difference between the actual weight and the estimated weight of all heads was *226 grams or 1.44 per cent*

Ten seed from the same heads were also selected at random in 1%8 and 1949, and four measurements made of each seed. Table XXIV gives the average measurements in the four categories and the average weight of the seed,

TABUS XXIV, Average measurements and average weight of seeds from 8 denes,Affcft T angth Length Width Width Average

no, glumes earyopsis glumes earyopsis weight4ft mm in am.... innm . in..mm tELfflfc

110 4.75 2#49 1*40 1*35 3282 4,57 2*54 1*60 1*45 4076 4*72 2.41 1*73 1*42 35297 4.60 2.67 1*30 1,65 4&5119 4.62 2,54 1*8® 1*65 538

69

Table XXIV* (Continued)CloneNo*

II-■SU-S length Width earyopsis glumes in mm In mm

Width earyopsis In mm

Averageweightin rm ...

30 5*35 2.70 1.96 1.67 53578 4*98 2*80 1.85 1.70 5405-0? 3.18 2.06 697

110 4.92 2 #49 1.70 1.42 2782 4*19 2*49 1.68 1.42 3376 4.82 2*44 ' 1.38 1.57 35097 4.52 2.51 1,68 1.47 372119 4.70 2*49 1.90 1.60 38930 4.82 2.49 1.90 1.57 38878 5.10 2.57 1.96 1.67 435m £*2L 1.80 592,Average1948-49120 4.85 2.49 1.55 1.38 3022 4.38 2.51 1.64 1.42 3726 4.78 2.43 1.80 1.49 35197 4.54 2.59 1.73 1.55 419119 4.65 2.51 1.89 1.62 46230 5.10 2.59 1.93 1.63 46378 5.03 2.67 1.90 1.67 48814 5*12 _ 3.19 2.03 1*82 645Averages 4.81 2.62 1*82 1.58 438

Measurement of the length and width of the outer glumes and the earyopsis of seed indicated that average relative sia© was characteristic of the clone, although rank might vary slightly under different seasonal and soil conditions#

The seed which weighed the least, that produced by clone Ho# HO, would run 136,654 seed per pound* The seed which weighed the most, that produced by clan© No* 14, would run 70,370 per pound#

70

The 1943 seeds which were measured and ten additional seeds with glumes on from each of the same heads were germinated in the laboratory, and the remainder of the seeds from the heads were geminated in the greenhouse. Results of the germination are given in Table XXV.

Table XXV, Germination of Seed from 8 clones Selected in 1948,

Clone Per cent Per cent Total seed Per centNo. Germ. Germ. planted of seedGlumes off Glumes on Xh Soil Germ, in Soil

2 90.0 60.0 630 49.66 60.0 50,0 545 17*414 90.0 100.0 360 54.430 80.0 70.0 334 46.478 90,0 100.0 430 66.397 50.0 30.0 475 25^110 90.0 80.0 206 59.7119 80.0 50,0 270 17.0

Totals andAverages 78.8 66.5 3250 42.0

Clones number 2 and number U0 which are in the lowest cate**gory of the earyopsis width and weight, and clones number 14 end 78 which are in the highest category of earyopsis width and weight Ail gave 50 per cent germination or better in each instance. Evidently earyopsis size and weight are not necessarily the factors determining germination of Johnson grass seed aa has been suggested. These seed differed in external appearance as well as size which may

compared in figures 7, and 8*

DISTRIBOTICM OF JOEBSON GRJSS SEED IK THE SOS

Studies Of Johnson p m i aeed as a aajLjacaadation la the 3M«ft sane areas of Louisians.

In the fall of 194-7, a start was made on determining the nmber of seed in the soil under different cultural practices and on different plantations. The number of seed recovered in samples from the different plantations varied from a rate of 0 to nearly 35,000,000 per acre. The number of seed recovered from samples taken from 16 plantations, and other related data are given in Table X3C71*

ifter preparation of the soil and planting of seed cane at St* Delphine plantation in October, 1947, samplings were made of the distribution of seed in the soil at six different depths* The camber of seedlings appearing in these samples after two months is recorded in Table X27XI. Except for a composite 3,3 lb sample of topsoil sifted through screen, from which 35 seed were recovered, no check was made on the number of seed present* Indications from this sample were that less than 30 per cent of the seed present had germinated during the twomonth period*

72

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74

Table XXVII* Ntsmber of Seedlings Germinating from St* Delphine Soil from Different Depths In 1947#

Depth in row ~ m —3.3 lbs.soil

.3*3 lbs* soil

— Bj— ■ 3.3 It*.soil

Average/2 Estimated seed petf

0*0 - 2*5*(1) 13 5 14 10.7 2*700*0002*5 - 5*0" 3 a 20 12*0 3,030,0005*0 - 7*5" 17 a 12 aWV;^' 3,106,0007*5 -10*0* 4 a 12 3*0 2f020,00010*0 *12*5* 1 0 64 21*7 5,479,00012*5 -15*0* 1 0 2 1*0 252,525

A * T7eight of 2J-* deep acre area of soil & 833*333 21* Conversion. figure % no* seedlings % 252*525(Soil collected from field which had just been planted to sugarcane*)

A series of samplings at this original location at St*Delphine was made through January* 1950* The field had been planted to com and beans In 1947 and was infested with Johnson grass* In August of 1947 the field was plowed to remove the Johnson grass rhizomes before the cane was planted# July 20*1947 was considered the last day on which seed were matured and most of the original seed were believed to have been produced in the spring and summer of 1947# Additional seed production was pre­vented# Since the plowing operation had distributed the seed evenly

75

in the soil to a depth of about 3.2 inches, this location was selected for a study of the longevity of Johnson grass seed under field conditions, table XXVIII records the germinable seed recovered at the level of the seed cane stalks for three years*

Table XXVIII. Germination of Johnson grass in a sugarcane field at St. Dolphine plantation from 1943 through 1950*hate soil collected age seed

Ho. 3.3 lb. samples

’ No* gexriin* able seed oer acre

Per cent <originalno*

larch 19* 1943 8 mos. 12 4,124*617 100*0April 3, 1949 20 mos. 18 701,514 17.0Hov. 9, 19149 27 mos. 18 56,119 1*3Jan. 29, 1950 30 mos. 18 14,022 0.4

At the beginning of the third spring following production of the seed* less than pfle per cent of the seed were still capable of germination*

In order to determine the effect of overwintering in the soil on germination of Johnson grass seed* the fields which were sampled in the fall of 1947 were sampled again in March of 1943* Table XXH gives the results of germination in samples from four fields which were heavily infested with Johnson grass seed.

76

TABLE XXIX, Estimated increase in germination of Johnson Grass seed after overwintering in soil, (In thousands)Plantation jjfajft 3-aj3EZI loil oolleoteasampled No, seed No, seed No* seed No* seed

recovered germinated recovered germinated------------------------ BBUffiML m< „ W ______mr acre TSt. Dolphins 8,838 2,700 1,936 2,104St, Louis 4,545 1,515 235 235McCall 2,272 505 1,763 2,778Billeaud 2.525 ..75.7 51&39 Af39?Average 4,545 1,369 2,399 2,357Par cent gemination ' 30,5 98,3

Although the sampling was not extensive and the individual counts varied, the averages indicate that about the same percentage of seed germinated in the fall of 1947 «s germinated in seed sampled collected from the same areas in the fall of 1947, (fable X?),

Table XXX shows a comparison of seeds germinating in 157 soil samples in the greenhouse, and the number of seed recovered and germinated in Petri dishes from duplicate samples,

Table XXX, Geiminability of seed overwintering in soil in 1947-48.

Area No, planta­tions sampled

No. soil samples

No* seed No, seed germinated germinated in in soil Petri dishes

Miss, River 7 115 595 548Lafourche 5 24 49 49"Teche & Laf, 2 9 66 76Red River - .9- 74.. ,99...Totals 16 157 784 772

77

Rewults of these tests *1** Indicate that after overwintering gexsdnabllity approaches 100 pen cent*

2h order to obtain some Mot of the population of viable seed in the soil after a sea am of fallow plowing, soil ampllng*were made In the spring of 194® la field* fallow plowed in 1947,in the summer and fail of 194® &om field* fallow plowed in 194®, and & the spring of 1949 from field* fallow plowed in 194®* these fields were located on 19 plantations in %$ parishes, table XU summarises the estimated number of seed par acre re* saining as a residual population in the soil after a season of imjow plowing* Toe eajumiatea number of seea per acre infaiXGH*plowed lead la different areas was 66,178* its number ofseed remaining after fallow plowing was considerably higher In the Mississippi River area* While the average for this area was 106,120 per acre, fields were sampled at Ginelare, ft* Louis, and McCall plantations which averaged more than $00,000 seed to the acre*

& the spring of 194®, samplings were made frrn stubble case fields with a heavy infestation of Johnson grass plants* the population of seed in fields cm 10 plantations In 9 parishes I* given in table XOTI* The number of seed per amm ranged from 105,000 to over 10,000,000, with an average from the ten planta­tions of over 1,650,000.

Tat&e XXXI. Population of Johnson grass seed in sugarcane lands fallow—puLorTod i n 1947, 1948, and 1949 <xi 19 plantations in 13 perishes.

Year falloa^lowed Total no* Aroraga seed Estimate*notation Palish and year sampled 3,3 1b. per sample seed persamples acre

Klsaiscippd Riser AreaAlma Point Coupe 1948 1948 6 0.667 163,434Wastes?©? W* Baton Rouge 1948 1948 66 0.349 88,131Waste#©? W, Batcm Rouge 1948 1949 34 0.059 14,398Ginclsra W. Baton Rouge 1948 1948 63 0.246 62,121Cirtelai© W* Baton Rouge 1948 1949 109 0,844 213,131St. Belphim W* Baton Rouge 1947 1948 24 0.583 147,222St* Delphine W* Baton Rouge 1948 1948 9 n.~m 23,030St, Louis Iberville 1987 1948 4 1.000 252,525HihPS?g?&S92 Iberville 1948 1948 35 0.429 108,333Wmrgsom Iberville 1943 1949 27 0.519 131,060mom. Ascension 1947 1948 12 0.500 126,263McCal1 Ascension 1948 1948 42 0.119 30,050McCall Ascension 1948 1949 112 1.143 238,636Grsognaid St. James 1947 1948 6 04.67 42,171Grangnaid St.- Janies 1948 1948 12 0.000 0Baser*© St* Joim 1947 1948 24 0.167 42,171Reserve St- John___ .1942 1946 54 60r85S__Totals and Averages 661 106,120

Bayou Lafourche AreaGlenwood Assumption 194.7 1948 2 0.000 0Madswood Assumption 1947 1948 4 0.000 0Madem>od Assumption 1948 1948 6 0.333 84,091Uttl© Texas Assumption 1947 1948 1 0.000 0Greenwood Lafourche 1948 1948 2 0.000 0Hontegot Terrebonne 1948 1948 48 0.083 20,959

Terrebonne 1946 1949 64 0.024 6-060Totals and 15,873

Sear fallo® plo5?ed Total no, Average seed EstimatedPlantation Parish and year sampled 3.3 lb,

samplesper sample seed per

acre

Bayou f eche imd Infayette .Area Maiyland St, Mary 1948 1948 6 0,000 0Albania Iberia 1947 1943 6 0*000 0Albania Iberia 1943 1943 6 0,167 42*172Orange Grove Iberia 1947 1943 6 0,000 0Itfllflgri T-afa-mWat 13£7 1368 6__________MS22--------Q___Totals end Averages 30 3*434

Meeker RanidesRed R i m Area 1947 1948 9 n-ui 28f03G

Total and Average 847 66*173

ao

Tab!© XXXII, Seed Population of Johnson grass in infested stubftL© ean© from lo plantations in 9 parishes.

Location Parish No* soil samples No* seed per acre

dim Point Coupe 6 10*227*263Wectcrror W* Baton Benge 2 757*575McCall Ascension 12 mewA ' iwirMN*778,575Be serve St* John 40 336,161Hadewood Assumption 4 3,478,219fiaeeland Terrebonne 2 631,313Hootegut Terrebonne 12 105,219Orange Grove Iberia 6 1,010,100

Lafayette 6 4,966,409Shirley Avoyelles n&mmm*

Totals and averages 96 1,657,195

SftTTtpi ingg *ere made in the spring of 194& at three plantationsin fields in which a crop of com and beans had been planted in 1947 in a rotation following Johnson grass infested stubble cane* The Helds of corn wad beans ware then fallow plowed to remove rhizomes after the crop was harvested* end planted to sugarcane* Samplings were also made on the same plantations from fields that had been fallow-flowed throughout 1947 and in which no seed were set* The comparison of the results obtained under the two cultural practices are presented in Table ZXXHI,

si

Table XXXIII, Comparative numbers of seed of Johnson grass in fi&ms where com and beans were planted in 1947 and in fields w&Lch were fallcrw»plowed in 1947 and in which no seed were produced.

locationFaliow tjiawed 19£7 Per cent

destroyed by faUrni-nltnmdNo, soil samnleB No, seed

.acre.No, soil No, seed

tser acreSt, Delphine 12 2,904*038 24 247.222 94*9McCall 4 2,272,725 12 326,263 94*4Beserve 12 i*m i a a 24 j & m . 07-0

Averages 2,388,139 103,303 95.3

The average number of seed present in the fields in which com and beans were grown and in which seed were set during 1947 was mot 20 tines greater than where fallow plowing was practiced and no seed had set.

Table XXXI? records a brief comparison of the differences in seed populations in the soil when different cultural practices are followed. After the production of seed in badly infested stubble cane the soil population of seed averaged over 1,600,000 per acre*In fields which had been fallow-plowed and in which no seed had set, the population in the soil averaged 66,000 seed per acre* la fields which had been planted to com and beans and then plowed to remove rhiscraes, the late rammer fallow had failed to destroy an average of 2,239,000 seed per acre. These seeds remained as a soil popula­tion to serve as a source of reinfestation of plant cane.

82

Table XXXH. Comparison of the population of Johnson grass seed in infested stubble* faUow-plowed fields* and fields which had been planted to com and beans and summer fallowed to remove rhisanea.

Description No.fieldssampled

Mo. planta­tions sampled

No. No. need samples Average

.per aero in Lowest

thoiiMmdHighest

Infestedstubble 10 10 96 1*657 105 10,227land fallow*plowed 29 19 847 66 0 229Com and beans* then suGBa&r fallow to remove 3 3 23 2*239 1,389 2,904

Hi the sparing of 1949 the excessive rainfall and waterlogged soil interfferxed with to fallow-piow two fields of stubble cane at two locations in the Mississippi River area. As a result a heavy seed set was produced before the fallow plowing program was begun about the first of June* and the seed were plowed into the ground during the operations. Table XXIV presents the estimated number of seed per sore which were still present in the soil at the time the seed cane was planted. The plant cane in these fields was found to be infested with Johnson grass seedlings in the boot stage ten weeks after the cane was planted. An average of 59 per cent of the seed present in the soil samples had germinated in two months* but 41 P®T cent re* mained ungerrainated.

83

Table X3QHT* Residual potmlatian of Johnson teas seed in August plant came at two locations fallow plcwed In 1949 after seed set of May* 1949 was plowed under*

PlantationHo*

3*3 lb. samplesKst. seed germinated par acre

He* 3*3 lb* samples

%at* seed per acre

EvergreenOinclare

606$ 172*558 2932 182*863

M lTotals and Averages 126 286*596 61 563,007

Probable no* seed overwintering In soil 276,411 (41#)

Table XXXVI records the seed population in a plant cam field at Evergreen plantation in which an estimated population of 2*078*070 seed per acre remained after fallow plowing to remove rhizomes follow­ing a crop of com and beans* Cnlfciyatiteipractices thereafter were routine* but somewhat timed to interfere with seed set* although there was some additional seed production* The seed population was reduced to 64 per cent in April, 1949* However* when sampled for the third time in the row at shave and off-bar in January* 1950*22 per cent of the original population* which remained after the plowing operation* were found to be still present and capable of germination*

84

Table XXXVI* Johnson grass seed population in a plant m m field at Evergreen plantation which had been plowed to destroy rhissomes after 003m and beans in 19*4# and subject to routine cultivation thereafter*

Month and year No* Estimated Per Cent ofof samplings 3.3 lb* seed per originalsamples acre number

October 1948 40 2,078,070 100*0April 1949 56 1,323,126 63*6January 1950* 13 462,962 22*2♦Sampled at time of shave and off«bar* Some additional seed setin 1949*

2n March of X94# two fields located on different plantations, which were found to have an average residual population of Johnson grass seed in the soil of about 200,000 seeds after a year of fallow plowing, were selected for special studies* The germination of seed in these fields apparently approached 100 per cent during the follow* ing two mouths and the seedlings which appeared were partially destroyed during routine cultivation* When no further seed were recovered in samplings of the soil, the Johnson grass plants which had not been destroyed during cultivation were hand rogued frcm the plant cam to prevent any further seed set* The results of this treatment of the plant cane are recorded in Table XXXVII* No seed were recovered from the samples taken from these fields, in which first stubble cane was then growing, in April and May of 1949*

05

Te&Lo XOTtX* Population of Johnson gras© saed in the soil at tewt locations falXwi*»lawed in 1%% fdUamd by band rogmi&g of pXsrrt can© in 3$$B*

i&ernaiTtatifl® icntli

scBgdsd«*•

maplesintimated seed per

acta¥e3r 'eS'1...ic *L 13&S*month eaBpleS matol

seed P®3P

St. Do^tdai March 1940 12 April l<&# 6 0Sept. 19<f3 9 0iprU 1969 18 0

Baacrve March X$0 6 136,263 3rs» 194.9 11 0«N»M»

Totals end Ammgoa 28 210*180 62 0

Cm October 29* 1%% studies were initiated an the rasabar asd condition of seed tfoSch ware lodged between the leaf sheath end stalk of sugarcane in 17 fields at 6 locations* in Tafalo SOT1IX are recorded the :. sta on the field sampled, the degree of grass infestation, and the nunber of seed recovered. The i»ter of seed recovered varied widely* Ho seed mm recovered 3n OT$0inge from too of the fields at MoGalX, chile an average of mam Urn. <m seed to a sheath was recovered in three fields of cans at EVdrgrosn plzsrfcaticm* There was ccmiderabla variation also In the axabor of flood recrrvored from samplings of different fields m the mgo plantations thoe^i sods seed sere recovered in samplings from Ct least oeao fioM cm each of the plantation© sampled*

86

of germlnsble eee t recovered wham found lodged between the loaf sheath and the stalk of sugarcane in plant cane fields and In first etubbl* fields «ta compared to the field of cane at McCall which was totally free of Johnson grass in* festatioa la given in Table MPQU the seed mrnmmd m m largely domant, hut when germinatien teats were made two months later, 211 of the 242 seed teeowerod from the plant oaae samplea geminated, and 102 of the 133 seed from the first stubble samples germinated, for an average germination of 83.5 per sent*

Table XXWI1I. Survey of sugarcane fields for Johnson grass seed lodged between the leaf sheath and cane stalk*

Plantation Bate Description of field

Degree of Johnson grass infestation*

No* seed recovered

1* Evergreen 10/29 Plant cane 4 S3a* Cinclare 10/29 HLcait cane 2 23* Evergreen W A Plant cane 4 854* Westover ll/ll 1st stubble 2 25* Estover 1 V U Plant cane 3 106* St* Louis n/n KLanfc cane 4 57* Evergreen XLfil Plant cane 4 10S* McCall n/a Plant cane 0 09* McCall u / u 1st stubbie 4 81s’•QH u / u 1st stubble 2 211. Bestcrver 11/L8 Plant cane 3 2312. Hestovep liylS 1st stubble 2 713. St. Louis 31/30 Plant cane 4 714* Evergreen 31/30 1st stubble 5 10115. Evergreen 31/18 Plant cane** 4 1616. ifcCall XL/18 1st stubble 4 1317. IfcCall 11/18 1st stubble 4 0

*Degree of infestation* l*no infestation* 2-moderate infestation outer 12 feet* 3»heavy in- festation outer 12 feet* 4-raoderately heavy infestation throughout* 5-very heavy infestation throughout***2)uplicate sample in soH in greenhouse*

SB

Table XXXIX* Germination of Johnson gras© seed recovered between the loaf sheaths and stalk of sugarcane.

No, fields sampled Ho* nodes

(sheaths) examined ,

Inscription Ho* He** field covered

Ho*germ,

Per cent • genft.

1 SOD Plant cane freeof Johnsch grass 0 0 0"9 720 Infested plant can© 242 87*2

7 560 1st stubble .133 102 76*7

17 1360 Plant end 1st sthb* 375 313 33*5bio

Table XL* Frequency of location and total number of seed lodged between the sheaths and stalk of sugarcane* by nodes*

Sheath ofNode Ho. ..... - _ He- field reorassated

Ho* Seeds

3 6 384 10 565 11 806 13 667 10 528 11 339 9 2710 8 23

Total Seed Recovered 375

By March 1950, five Johnson grass seed protoed seedlings in the duplicate sample from Evergreen plantation pianbed in soil, indicating that seed lodged between the leaf sheath and staXfe were capable of gemination when planted with the seed cons*

Table ZL records the frequency, according to the number of fields sampled, of the location of the seed, based an the node at which the sheath was borne j and the total mraber of seed found at each sheath. Seed were found with greatest frequency at the sheath of the sixth node, being found at this position in can© from 13 of the 17 fields sampled, but seed were also found in each sheath from the fourth through the ninth node in at least 10 of the fields. The largest number of seed recovered at any one node, do, were found at tbs fifth node where they apparently lodged on shattering from the heads of Johnson grass. Seed were also abundant at the fourth, sixth and seventh nodes. Seed found in the eighth to tenth sheath in November, 1949, were frequent3y immature. For example, in West ever first stubbie sampled on November IB, 1949, three full heads were found at these locations, but no mature seed capable of germination were present. In the first stubble from Evergreen the same day, racemes from three heads were found, and seed from these contributed to the total genainable seed recovered from this sample* It has been noted that seed cane fce'fog transported for planting, had heads of Johnson grass caught between the sheaths and stalk.

DISCUSSION

Johnson grass seed were found to geminate best at al* tcmating temperatures, which is in accord with previous reports* Temperature changes, whether they included a drop from a previous high or a rise fro® a previous low temperature, were frequently followed by the appearance of large numbers of seedlings from the weed planted in flats in the greenhouse. This has also been noted to occur in sugarcane fields in the spring and the fall at the time of gemination of the buds of sugarcane pieces, This may contri* bribe to difficulties in the field control of this weed pest, since both Johnson grass seedlings and the sugarcane frequently appear at the soil surface about the same time.

While the germination of seed lots of Johnson grass collected in Louisiana was found to vary greatly, the seed when freshly harvest* ed were nearly always in a condition of initial dormancy probably not associated with the embryo or endosperm, but with the caryopsis coat,During the period of initial dormancy, most of the seed failed to germinate even with the glumes removed. The average period of ini* tial dormancy in the seed collections of 19-4-7 and 19-4® was about 12 weeks. The initial dormancy of seed from collections made in 19-49 was not as well defined, and extended over a longer period* When the seed collected in 1947 and 194® were germinated with the glumes removed 12 weeks or more after collection, 90 to 95 per cent of tho seed germinated.

90

91

HSien seed hqtg tested for germination in 194-9 with the glumes re- moved 18 weeks or more after collection, 80 per cent gorriinated#If the glumes wore not removed from these seed which had passed the period of initial dormancy, germination averaged 50-70 per cent less in the tests in the laboratory, and considerably less in the soil, than the germination of seeds from which the glumes had been removed#A secondary dormancy associated with the glumes was indicated#

In Johnson grass seed with the glumes not removed, the en* casing glimes apparently prevent the entry of sufficient water and gases to meet the gemination requirements of the seed, since the thick-walled distal portion of the caryopsis, which is relative­ly impervious to solutes, would be the only part exposed between the glumes. It is possible that both relative impermeability to solutes and the presence of an inhibitor, account for the failure of most materials to rapidly affect the germination of Johnson grass seed when thus imbibed# It has been suggested by Thornton (28) that secondary dormancy of these seed may be due to their relative im­perviousness to oasygen as well as solutes, and in this case an accumulation of inhibiting substances, developed during partial anaerobic respiration, would further interfere with the oxidation

system#The most effective chemical tested for the production of an

increase in the germination of the seed was thiourea, which ffutila (19) reported as capable of breaking dormancy of certain lettuce seed#

92

It is possible that coumarin, or its derivatives, or compounds closely* related to it, may be present as an Inhibitor, and that thiourea inactivated this compound*

Certain other materials apparently produced some change in portability, or in sane nay inactivated an inhibitor* The most effective material was soil* In most eases seed planted in soil soon after collection germinated appreciably better than when sub* jected to germination tests in water, though the poor gemination of seed in Red River soil cannot be easily explained* Only after burial of seed for long periods was germination recorded as approach* ing 100 per cent* It was found that there was a highly significant difference in the ability of seed collected in different years to geminate when planted in the soil soon after collection, although the seed collected in different seasons of the same year did not differ materially* However, the seed collected from the Mississippi River-Lafcfurche area did not germinate as rapidly in the same period of time in the soil as did the seed collected In other areas* If seed produced in this area failed to germinate as rapidly in the soil in the sugarcane fields when exposed to favorable conditions during a fallow plowing program, this could contribute to an explanation of the larger residual seed population in the soil after fallow plowing

in the Mississippi River area*Clonal differences were recorded in pollen sise and amount of

full pollen which apparently occurred at microsporogensis and were

93

interpreted as evidence of partial sterility# It is possible

that both the amount of pollen produced and the genetic character

of the pollen produced contribute to the ability of the clones to self pollinate* Self pollination of Johnson grass clones was found

to divide into four classes. Self pollination did not occur in the

first class, and averaged only about 2 per cent in the second class*

In the third class self pollination occurred frequently, but there

were differences between clones in the percentage of self pollina*

tion. The fourth class was capable of 100 per cent self pollination.

Since Perkins (21) first mentioned that Johnson grass rarely

produced good seed in Louisiana there had been a belief that few

seed were produced and that these would not germinate, Arcenaux

(2) reported that the ®ed produced by Johnson grass plants was not

the same in different parts of Louisiana. In 1947 and 194$ collections

of heads of Johnson grass made at Youngsville plantation were found

to be completely lacking in seeds, nor were seed ever produced on

clones collected from this plantation when self pollinated* How**

ever, when these clones were open pollinated, normal amounts of seed

capable of germination were produced. It is possible that the

population of Johnson grass plants in south Louisiana at the time

Perkins made his survey in 1916, and for many years thereafter,

was composed largely of clones which did not self pollinate, or

which seldom self pollinated, and that there has been a gradual

increase in the number of clones in which self pollination is common.

94

At the present time several, and possibly a great number of strains

of Johnson grass are probably present in the sugarcane areas of

Louisiana, These strains differ in ability to produce seed under conditions of self pollination and occasionally in external ap­

pearance of the seed* None of the clones which were collected and

brought to Baton Rouge for further study failed to produce seed

when open pollinated* None of the seed collections tatesn from

clones throughout the sugarcane area of Louisiana and brought to

Baton Rouge for germination tests were incapable of germination*

The total nimiber of seed present in some of the collections was

small, and these were probably collected from clones in which the

degree of self pollination was low, and in an area where compatible

pollinators were not present. It was because several of the seed

collections were relatively small, that extensive replications of

germination tests were not made* Probably there are still areas in

tbs state where the number of compatible pollinators are ©nail, and

this may be true of some of the more Isolated fields on some of the

plantations. The number of self pollinating clones and compatible

pollinators in a field, as well as the degree of infestation, would

contribute to the number of seeds which would be found in the soil

population.

Indications were that seed found in the soil the year the seed

wore set would germinate about the same in a two month period as seed

collected, from the same location and planted in the soil* Hot until

95

tho seed had overwintered in tbs noli war© they capable of germination

approaching 100 per cent* The interaction of several factors would

deteirrtne the number of seed destroyed during a fallow plowing pro*

gran to remove rhizomes during late summer* Among these would be

the number of seed produced, the degree to which the seed produced were

affected by the soil, the relative numbers of seed In initial and

secondary dormancy, and the temperature conditions at the time of

fellow plowing* When such a program of fellow plowing followed

after c o m end beans under conditions in which the seed population

in the soil was extremely large, the residual population left in the

soil was over twenty times greater than the average residual population

remaining when the fallow plowing was done the year after seed set*

The increase in seed population in the soil was traceable from the

residual soil population through the plant and stubble crops to

c o m and beans, if used in rotation* Once a fellow plowing program

was initiated the year after seed production, and every effort ex­

pended to prevent farther seed production in the plant cane, Indies*

tiens were that the stubble crop would be practically free of Johnson

grass infestation*

It ums found possible that additional seed could be added to the

2©eidual population in the soil by planting seed cane in which Johnson

grass seed were lodged between the leaf sheath and the stalk* Hot

only the addition of seed to the residual population, but the intro*

ducticoa of seed of Johnson grass which would produce good pollinators or

were highly self fertile could be accomplished in this way*

smmmi

1* A period of initial dormancy of Johnson grass seed was indicated. Seed in initial dormancy did not germinate when removed tem the glance,

A secondary dormancy associated with the presence of the glmes was indicated, , When the glumes were removed from seed in second* ary dormancy gerjoinatim increased 50*70 per ©eat. When seed in secondary dormancy were treated with thiourea the geralnatim with the glumes on was accelerated and increased, ,3, Seed was capable of germination approaching 100 per sent after overwintering in the soil,4, Clonal types mere found to differ in ability to self pollinate* htzt all denes wore capable of seed production in the presence of compatible pdliaarfcors. The abundance of compatible pollinators and denes with the ability to self pollinate eoatrlMe to dlf* fereutid populations of seed in the soil,5, Odtnrwl practices were shown to contribute to differential populations of seed In the soil,6, Beinfestatim of fields of sugarcane after fallow plowing are largely txm the residual seed populations which failed to geiminate.7 , Seed lodged between the leaf sheaths and stalh of the seed cane pieces may contribute additional seed to the soil population.

%

Jtomim* B. K*AgpPjt

Mowwtt, V ft P*«f «* flfftgftpy&g

Bronoblty! Haiiyoif and Tftodaglsaa*r f ijflfWffl-'ffitfl T» J w . BM l* is ?

Croefce*, ■♦ MS Da*i., W, E.Bot. (tea.

exoatar. *.Dl 9 W & *

5»jwfc*IISn.tf.AffMffifCTA.mSiU — •

la aeeda of

Crocter, V., Tbowrteo. i« «a& Sobroeder,or*M «teM a_laLa^gA (StmiH.ls. Bojns*Thonp. Xhefc. 14* 17>B03. 1946.

MawSe, X. I. tt»lajiliiWI J f,. ITMBtfIWIt,£id jflM tih ,jg jm iatliifla ,fthw». & • W ysm . 9> i - 3Q. 1934.

2183Goto, V. I.*Agxi* fed* 2t» UBM35*

Herrington, 6oarg*#N£88U£S&* I^efi4« Xsooe* Offl** Se teerica Ml

• tftl&P * Dept*

ets <tf Ho,.6 and M M V 24-26*

* Itethw. atndtftg ,srf..,^^EffltoMgL3E,fift ftNo. &»rioa

4r«wp«w * Asoec. 1917* 71-76*

MLg<mr# Agrl. ■jim-teJte,, li 295-333. 1983.

letmrt. and cUftJWMlfi Agxi. See. 23.

# and Crook**, V.

ftj&EiMsgg* *— *«1923.

IS . ifeteg*, i* AjBaStwlfiiit,

34.

35. Hitehwwk, A. 8,0*S. B, A* Mitt** Pafelle

14* Risking, 6* I*., *n&% T i m

GeneS* 0* ^as ■■ SLML

17.

10. K*Xg*¥t $* £*' t. 1

« n gHSMSBXh• *92

24 s

19. feniifi, o* kH* Ptaystel*20i 43>44^ 19®.

20* Oakley, R. A* g fin g J » B U B ||p B .|^ Apiculture 191 * 495 504* m i21* Perlons, W* R.

t* Xeayhook of

a i»ouiaA*j&a State tMverelty Agrie* Exbea, Cira. Ho* 10* 1*-?. 1914*

«&£ael* South*

Journal* Vol.

22. Phillips, R. P., and ChUteft, S. J-. P*TTood Go d x. 59-60. 3967.

23. Rdlllya, H. P., and Chilton, S. J. P. m m ^ Tb©

24. Stelb, R. J. Jotewm gg*M a w d WMdJaKtlon.Jomwtl 7®3. 30. Ro* 34—35.3947.

25. IhnpaflB, R. 0.. and Koaar, W. P. Jfes,read stimulated ter ahtmloal ttaataank. Soienoa 87t 238*239 1938.

wf

gsnalnntlen .of aoraant lgttw; aeafl to f tfffr*»*'•' m m w . h w .

27, Shorter, 3, 1. the Tifiblllty ofaeedB.. JOant World H* 158-159. 1939.

28. Thornton, H, 0, JwMEliMP. a tti^ |» lr te ',te l SSmfatt,,,rnwniiir imi toregulating dormagau Contrtt. Boyoe Tboap. mat. l3t i&MGa. 194*; ;■'.

29. Vlnall, H. K, Sudan arasaaB a foraee ero«». W. S. D. A.Earner** Bul. 6C5. l-Sl). 1914. ■ ,

30. Waringfcon, Katherine, Tfaeegfeet eotistantSam m to . mb. Ib .wtasfla.J*, Jour* molm 26i i M O 4* 1936*S * Teang, H. J . Johaeca >»i««

lBB&flml as a fora^ iwBalbllitr for south TtopMlzbBd Master’s Theede L. S. U. 1935*

autobiography

Mrs* Ruth Patterson Phillips was bora Rath Eleanor Patterson in Kiel* Wisconsin, October 13, 1913* In Jane 1931, she graduated from Pasadena High School, Pasadena, California, and in JWae, 1934, from Pasadena Junior College*She completed her junior work at the University of Wisconsin and entered Louisians State University in February, 1937, receiving her B* A* degree in June, 193#* In August, 193# she was married to William Russell Phillips*

She was an Assistant in Zoology at Louisiana State University from October, 1942, through lay, 1944, being en<* rolled also as a graduate student* From May, 1944, through June, 1945, she was an Instructor at John MeNbeee Junior College, Lake Charles, Louisiana* In June, 1945, she enrolled for graduate studies at Louisiana State University, receiving a Master of Science degree from the Department of Botany, Bacteriology, Plant Pathology in August, 1945* Jh September, 1947, she enrolled for further graduate studies at Louisiana State University end served as a Graduate Research Assistant in botany* She is a candidate for the degree of Doctor of Philosophy in August, 1950*

100

LBHEKD FOE PLATES %

PLiffiE 1*

Figure 1,

Figure 2*

PLATE II*Figure 3«

PLATE HI.Figure 4.

PLATE IV*Figure 5*

Johnson grass seed soaked 18 hour®, followed V teaching in 5i er cent sodium hypochlorite*A belt of unbleached earyopsia ooat remaim in the center of the earyopsis where the glumes were not destroyed*Germination with the glumes removed showing from left to right* the imbibed earyopsia, the rupture of the oaryopeie ooat over the coieorhisa, and the further splitting of the earyopsis coat as the plumule develops*

Percentage germination of Johnson grass seed at three different tine intervals after the passage of initial dormancy* drey bars indicate the seed with the glumes not removed * Black bars indicate the germination of seed with the glumes removed*

Germination of seed from three collections after the passage of initial dormancy* Top row of seed with the glumes removed* Bottom row of seed with tbs glumes not removed* Per cent gemination from left to a-ighti Meeker, glumes removed, %% * glumes on 26£j Billeaud, glumes removed %% » glumes on 16 per cent; Southdown, glumes removed 9256 - gtaes on 3£# Figure 4 fhotographed after 90 hours in the Petri dishes*

percentage germination of Johnson grass seed from collections tested in 194# • Grey bars indicate seed frcro which the glumes were not removed*Black bare indicate seed with the glumes removed*

102

PUSS V,Figure 6,

FUSE VI,Figure 7,

Figure 8.

Percentage gemination of Johnson grass seed from eolledtlone teste in 1949. Grey bare indicate the germination of seed from which the glumes were not removed* Black bars indicate germination of seed with the glumes removed.

Seed from done #110 on the top row* Glumes averaged over 4*5 mm* in length and about 1*5 mm, in width* Weight averaged 302 mg* per 10 seed*Seed from clone $L4 on bottom row. Glumes averaged over 5 mm* in length, aid 2 m, in width. Weight averaged 645 mg* per 10 seed* Glumes were heavily pubescent.Seed from clone #1 on the top row. Glumes averaged slightly under 4*5 am* in length and about 1*5 in width, weight ranked in lower division.Seed from clone #78* Glumes averaged about 5 mm* in length and slightly under 2 mm* in width.Weight ranked in upper division. Glumes were heavily glabrous in certain areas.

Plate 2

m

Fig, 2

Plato II

d a y s

Fig* 3

Plate i n

Fig.

% G E R M I N A T I O N

Ol <71 CD <0

1 ' 1--

*1H*OTJ•Vfi

HfJer-o

% G E R M I N A T I O N

Plato ¥

Plato VI

Tig. 8

EXAMINATION AND THESIS REPORT

Candidate: Ruth P . P h illip s

Major Field: Botany

Title of Thesis: Studies on the G erm ination , Production, and D istrib u tion ofJohnson grass seed in ce rta in areas of Louisiana

Approved:

Major Professor and Chairman

Graduate SchoolDean of

EXAMINING COMMITTEE:

______

Date of Examination:

j y