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potato Research 38 (1995) 47-52

Wild potato (Solanum sect., Petota) germplasm collectingexpedition to Mexico in 1993, with special reference toSolanum bulbocastanum Dunal and S. cardiophyllumLindley

AARON RODRIGUEZ1,2, OFELIA VARGAS2, EDUARDO VILLEGAS2, ANDDAVID M. SPOONER]

1 Vegetable Crops Research Unit, Agricultural Research Service,United States Department of Agriculture, Department of Horticulture,University of Wisconsin, Madison, Wisconsin 53706-1590, USA

2 Institutode Botanica, Universidad de Guadalajara,Apt. Postal 139, 45110 Zapopan, Jalisco, Mexico

Accepted for publication: 3 October 1994

Additional keywords: subspecies, taxonomy

Summary

A joint Mexico/United States expedition. collected wild potato (Solanum sect. Petota)germplasm in Mexico between August 1-31, 1993.The purpose of the expedition was to expandgermplasm and herbarium collections of S. bulbocastanum and S. cardiophyllum. Collectionswere made from west-central to southern Mexico, and comprised 19 true seed and 37 tubercollections (45 collections in total) of 9 species and two putative natural hybrids.

Introduction

Mexico has been the focus of many germplasm collecting expeditions, but someMexican species are still underrepresented in the world's genebanks relative totaxonomic and geographic coverage (Spooner et aI., 1991). The latest taxonomictreatment of sect. Petota (Hawkes, 1990) recognizes three subspecies in S.bulbocastanum Dunal (ssp. bulbocastanum, ssp. dolichophyllum (Bitter) Hawkes,ssp. partitum (Correll) Hawkes), and three subspecies in S. cardiophyllum Lindley(ssp. cardiophyllum, ssp. ehrenbergii Bitter, ssp.lanceolatum (P. Berthault) Bitter).

A recent chloroplast DNA study (Spooner & Sytsma, 1992) revealed unexpectedmaternal relationships between S. bulbocastanum and S. cardiophyllum (placed byHawkes, 1990, in ser. Bulbocastana (Rydberg) Hawkes and ser. Pinnatisecta(Rydberg) Hawkes respectively). Similarly, these species showed similarities in lightsprout morphology (van den Berg, 1993). We wished to further investigate thesesurprising results with additional accessions, molecular markers, and morphologicalstudies. The purpose of this expedition was to increase the geographic and taxonomicrepresentation of S. bulbocastanum and S. cardiophyllum necessary for these studies,and to collect germplasm of any other members of sect. Petota encountered.

Potato Research 38 (1~95) 47

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Collections in Mexico, 1993

Fig. 1.Map of routes of the 1993Mexico expedition. The numbers refer to generalizedcollecting sites (see Table 1).

48 Potato Research 38 (1995)J

Table 1.Summary of collections of Solanum sect. Petota from the 1993Mexico expedition.

Taxa Seeds Tubers Total Mapcollections locations

Solanum brachistotrichum 0 1 1 3S. bulbocastanum 6 7 9 1,4,11,12,15S. cardiophyllum 4 14 17 2,5,6,7,8,9,10,12,13,14S. cardiophyllum x S. bulbocastanum 0 1 1 2

S.pinnatisectum 2 2 3 6,9S.polyadenium 0 1 1 10S.polytrichon 4 4 5 9,10S. x sambucinum 1 2 2 8,9S. stenophyllidium 0 1 1 3S.stoloniferum 2 2 3 11,15S. tuberosum 0 2 2 2,13

WILD paTATa GERMPLASM CaLLECTINGEXPEDITIaN TO.MEXICO. IN 1993

Materials and methods

Radriguez, Vargas, and Villegas callected fram west central to. sauthern Mexico.between August 1-31, 1993 (Fig. 1). We abtained lacality data fram Carrell (1962)and the Natianal Research Suppart Praject-6 (NRSP-6; farmerly knawn as the Inter-Regianal Patata Introductian Project, IR-1). We mapped lacalities an 1:250,000-scale tapagraphic maps purchased fram the Instituta Nacianal de EstadisticaGeagrafia e Infarmatica. Precise latitude and langitude data (to. a precisian af a 300m radius) were abtained in the field by a Glabal Pasitianing System "Trans-Pak IF(Trimble Navigatian, Sunnydale, Califarnia, USA). Callectians cansisted af 19 trueseed and 37 tuber callectians (45 germplasm callectians in tatal) af 9 species and two.putative natural hybrids (Table 1).

Germplasm was divided equally between NRSP-6 and the Pragrama Nacianal dePapa, Instituta de Investigacianes Farestales y Agropecuarias. Twenty-seven af theseare af S. bulbocastanum and S. cardiophyllum (Table 1; Figs. 2, 3). We depasited setsaf herbarium vauchers at the herbarium af NRSP-6, the Instituta de Batanica,Universidad de Guadalajara, and at the Department af Batany, University afWiscansin-Madisan. Detailed field trip reports are an file at NRSP-6, the UnitedStates Germplasm Services Laboratory in Beltsville, Maryland, and the InternatianalBaard af Plant Genetic Resaurces (bath the Latin America affice in Cali, Calambia,and the main headquarters in Rame, Italy), and at the Internatianal Patata Center inLima, Peru. In additian, alliacality data are avaii~ble an-line fram the United States,USDA GRIN (Germplasm Resaurces Infarmation Netwark) system. All callectianswill be available for distributian from NRSP-6 after passage through USDAquarantine and germplasm increase.

Results and discussion

Accounts af NRSP-6 germplasm from Mexico. are pravided in Bamberg & Martin(1993) and Spaaner et al. (1991). Priar to. the expeditian described in this paper,NRSP-6 maintained 45 germplasm accessians af S. bulbocastanum and 28 accessiansaf S. cardiophyllum (Bamberg & Martin, 1993).Excluding the intraaccessian hybridsmade in the genebank to. canvert callectians made exclusively as tubers into. trueseed, these numbers are reduced to.31 and 29, respectively. Our new callectians add 9germplasm accessians af Solanum bulbocastanum and 17 af S. cardiophyllum. They-fill in geagraphic gaps (Figs. 2, 3) and callectians fram type lacalities (Table 2) afthese two.species as last mapped by Hawkes (1966).

We currently are reinvestigating the subspecies classificatian af S. bulbocastanumand S. cardiophyllum with marphalagical and malecular techniques. We will providedeterminatians af aur callectians to.subspecies when aur studies are campleted.

Potato Research 38 (1995) 49"

AARON RODRIGUEZ, OFELIA VARGAS, EDUARDO VILLEGAS AND DAVID M. SPOONER

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- Solanum bulbocastanum ssp. bulbocastanum-. _.. Solanum bulbocastanum ssp. dolichophyl/um- - - - - Solanum bulbocastanum ssp. partitum. Priorcollections

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Figs. 2, 3. Distributions ofNRSP-6 germpJasm holdings of S. bulbocastanum and S.cardiophyllum, mapped over the distribution of the subspecies (Hawkes, 1966). Somedistribution points have more than one accession per area. We make no decision hereregarding identity of collections to subspecies.

50 Potato Research 38 (1995)~

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Table 2. Type localities of Solanum bulbocastanum Dunal and S. cardiophyllum Lindley, grouped under the synonymy of Hawkes(1990), indicating new collections made on the 1993 collecting expedition to Mexico. .

Taxon Newcollections

Type locality Priorcollections

Solanum bulbocastanum Dunal spp. bulbocastanumS. bulbocastanum var. latifrons BitterS. bulbocastanum var. glabrum Correll

S. bulbocastanum ssp. dolichophyllum (Bitter) Hawkes

S. longistylum CorrellS. bulbocastanum ssp.partitum (Correll) HawkesS. cardiophyllum Lindley ssp. cardiophyllum

S. cardiophyllum var. oligozygum BitterS. cardiophyllum var. pliozygum Bitter

S. coyoacanum Bukasov ex RybinS. cardiophyllum ssp. ehrenbergii Bitter

S. cardiophyllum var. ehrenbergii CorrellS. cardiophyllum ssp.lanceolatum (P. Berthault) Bitter

MexicoIMexicolMexico. Oaxaca: upper slopes of CerroSan FelipeMexico. Morelos: moist hillsides nearCuernavacaMexico. Morelos: El ParqueGuatemala. Baja VerapazMexicoIMexicoIMexico. D.F.: Cerro de Guadalupe,Valley of MexicoMexico. D.F.: nearCoyoacanMexicoMexico. Queretato: near QueretaroMexico. Puebla: calcareous hill nearTehuacan "

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IAcknowledgments

We thank Henry Shands and Calvin Sperling of the USDA, ARS for providingcollecting funds; John Bamberg and George White, USDA, ARS, for help inimporting germpiasm into the United States; Francisco Flores of the ProgramaNacional de Papa, Instituto de Investigaciones Forestales y Agropecuarias forcooperation in collecting in Mexico; J.J. Bos and Ronald van den Berg for commentson an earlier draft of the manuscript; and Andrew Wynn Rouse for artwork.

Names are necessary to report factually and available data; however, the USDAneither guarantees nor warrants the standard of the product, and the use of the nameby USDA implies no approval of the product to the exclusion of others that may alsobe suitable.

References

Bamberg, J.B. & M.W. Martin, 1993: Inventory of tuber-bearing Solanum species: Catalog ofpotato germplasm - 1993. Potato Introduction Station, NRSP-6, Sturgeon Bay, Wisconsin.104pp.

Berg, R.G. van den, 1993.Light sprout morphology of wild tuberiferous Solanum species. ActaBotanica Neerlandica 42:37-49.

Correll, D.S., 1962. The potato and its wild relatives. Contributions from the Texas ResearchFoundation, Botanical Studies 4: 606 pp.

Hawkes, J.G., 1966.Modern taxonomic work on the Solanum species of Mexico and adjacentcountries. American PotatoJournal43: 81-103.

Hawkes, J.G., 1990.The potato: evolution, biodiversity and genetic resources. Belhaven Press,Oxford, England/Smithsonian Institution Press, Washington, D.C., 259 pp.

Spooner, D.M., 1. Bamberg, J.P. Hjerting & J. Gomez, 1991.Mexico, 1988potato germplasmcollecting expedition and utility of the Mexican potato species. American Potato Journal 68:29-43.

Spooner, D.M. & K.J. Sytsma, 1992. Reexamination of series relationships of Mexican andCentral American wild potatoes (Solanum sect. Petota): evidence from chloroplast DNArestriction site variation. Systematic Botany 17:432-448.

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Potato Research 38 (1995)

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