Wheat (Triticum aestivum) cultivar response to … · crops, but the integration of plant growth regulators (PGRs) into intensive wheat production systems has also contributed to

Wheat (Triticum aestivum) cultivar

response to chlormequat chloride

(Manipulator®) treatment

An Undergraduate Thesis Submitted in Partial Fulfillment

of the course requirements of PLSC 494.6

in the Department of Plant Sciences

University of Saskatchewan

Saskatoon, SK

By

Andrew Reddekopp

March 23, 2017

https://www.google.ca/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwiTje3s4-bSAhXi5IMKHTX5CUUQjRwIBw&url=https://farmfoodcaresk.org/members-sponsors/&psig=AFQjCNGMn1PzF5Vv5qDIo5qlW_xTHl4QHw&ust=1490157614265031

i

Abstract

A study was conducted in north-central Saskatchewan to evaluate and compare

the effect of chlormequat chloride (Manipulator®) on 5 cultivars of hard red spring wheat

(Triticum aestivum) under field conditions. Two factors were examined: cultivar and

chlormequat chloride treatment. Seven parameters were used to evaluate the

performance of chlormequat chloride: yield, plant height, lodging score, protein content,

moisture content, test weight and overall grade. Cultivar x chlormequat chloride

treatment interactions were observed for plant height, lodging severity, protein content

and seed moisture content. Yield increases were observed in all cultivars when

chlormequat chloride was applied, but the interaction between cultivar and PGR

treatment was not significant for yield. All cultivars experienced height reductions and

lodging score reductions when chlormequat chloride was applied. Lodging response

appeared to be primarily dependent on PGR application rather than plant height or yield.

Chlormequat chloride reduced protein content of 3 cultivars by varying degrees, and was

non-influential for the other 2 cultivars. Moisture, test weight and grade were largely

unaffected by chlormequat chloride application. Response to chlormequat chloride

varied depending on the wheat cultivar, confirming the hypothesis.

ii

Acknowledgements

Many people helped make this project possible and I want to thank them for their

involvement. First, thank you to my grower cooperators Wayne Andres, Peter Unruh,

Jason Feitsma and Nic Wiens who directly participated in the field trials. Their time,

resources and diligence are what made this research not only a possibility, but a success.

Thank you to Brett Galambos who supported my work and helped me at many points

during my experiment. Thank you to Phil Bernardin from EngageAgro who supplied the

Manipulator® product for the trials and was a valuable associate throughout the duration

of this project. Thank you to Wendland Ag Services Ltd for facilitating the project and

providing a weigh wagon for the collection of harvest data. Thank you to the grain quality

lab at Viterra in Saskatoon for conducting the grain quality analysis for all grain samples.

Lastly, thank you to Chris Willenborg, my advisor, and Eric Johnson for helping me with

the experimental design, data analysis and the written portion of my thesis.

I chose to research this topic with the goal of gaining knowledge that would

benefit the local grain producers I work with on a regular basis. It is my hope that wheat

growers find the results of this study helpful for making management decisions and that

it will ultimately improve profitability on their farms.

iii

Table of Contents

Abstract ...................................................................................................................................... i

Acknowledgements .................................................................................................................. ii

List of Figures ........................................................................................................................... iv

List of Tables ............................................................................................................................. v

1.0 Introduction .................................................................................................................. 1

2.0 Literature Review .......................................................................................................... 3

2.1 Wheat Production in Saskatchewan ........................................................................ 3

2.2 Breeding for Lodging Resistance .............................................................................. 3

2.3 Gibberellin Synthesis and Roles in Plants ............................................................... 4

2.4 Plant Growth Regulators .......................................................................................... 6

2.5 History of Chlormequat Chloride ............................................................................ 8

2.6 Manipulator® ............................................................................................................ 8

2.7 Chlormequat Chloride Use ..................................................................................... 11

2.7.1 Global .................................................................................................................. 11

2.7.2 Saskatchewan ..................................................................................................... 12

3.0 Research Report .......................................................................................................... 15

3.1 Hypothesis & Objectives......................................................................................... 15

3.2 Materials & Methods .............................................................................................. 15

3.3 Results ...................................................................................................................... 19

3.4 Discussion ................................................................................................................ 29

4.0 Conclusion ................................................................................................................... 36

References .............................................................................................................................. 37

Appendix A: AC Harvest Field Management Information ................................................... 42

Appendix B: AC Carberry & AC Elsa Field Management Information ................................. 43

Appendix C: Morris Field Management Information ........................................................... 44

Appendix D: AC Lillian Field Management Information ...................................................... 45

iv

List of Figures

Figure 1……………………………………………………………………………………………………………………….…5

Figure 2…………………………………………………………………………………………………………………….….10

Figure 3…………………………………………………………………………………………………………………….….10

Figure 4………………………………………………………………………………………………………………………..16

Figure 5………………………………………………………………………………………………………………………..16

Figure 6………………………………………………………………………………………………………………………..16

Figure 7.……………………………………………………………………………………………………………………….18

Figure 8.……………………………………………………………………………………………………………………….21

Figure 9.……………………………………………………………………………………………………………………….21

Figure 10………………………………………………………………………………………………………………………22

Figure 11………………………………………………………………………………………………………………………23

Figure 12………………………………………………………………………………………………………………………24

Figure 13………………………………………………………………………………………………………………………24

Figure 14………………………………………………………………………………………………………………………25

Figure 15………………………………………………………………………………………………………………………25

Figure 16………………………………………………………………………………………………………………………25

Figure 17………………………………………………………………………………………………………………………25

Figure 18………………………………………………………………………………………………………………………26

Figure 19………………………………………………………………………………………………………………………26

Figure 20………………………………………………………………………………………………………………………27

Figure 21………………………………………………………………………………………………………………………28

v

List of Tables

Table 1…………………………………………………………………………………………………………………………. 19

Table 2…………………………………………………………………………………………………………………………. 29

1

1.0 Introduction

The drive for more profitable economic returns, increased fertility and favourable

weather has led to higher wheat (Triticum aestivum) yields in much of Saskatchewan in

recent years. Management strategies including cultivar selection, seeding dates and rates,

row spacing, pest control, and improved fertility regimes have increased the yield

potential in intensive wheat production systems (Shekoofa & Emam, 2008; Rademacher,

2009). Unfortunately, crop lodging often becomes concerning in high yielding wheat

crops. In fact, crop lodging is the most limiting yield factor linked to increased fertilizer

rates (Brandt, 2014). High seed and moisture weight in the spike and low stem resistance

are contributors to lodging, especially when there are strong winds or heavy rains late in

the growing season (Espindula et al., 2009). This can result in reduced crop yield,

decreased grain quality, extended dry-down time, increased disease potential and

hindered mechanical harvest (Espindula et al., 2009; Navabi, 2006).

Breeding of semi-dwarf cultivars at the onset of the ‘Green Revolution’ in the

1960s has been the most effective strategy to reduce the negative effects of lodging in

crops, but the integration of plant growth regulators (PGRs) into intensive wheat

production systems has also contributed to reduced lodging and increased yield

potentials in these systems (Claeys et al., 2014). PGRs have been studied for decades,

primarily on winter wheat in Europe, but the recent registration of chlormequat chloride

(Manipulator®) in Canada has sparked interest among wheat researchers and producers

in Saskatchewan. Chlormequat chloride (2-chloroethyl-trimethyl ammonium chloride) is

2

a PGR that can reduce plant height (Shekoofa & Emam, 2008), increase stem strength

(Miranzadeh et al., 2011), increase drought and cold stress tolerance (Emam & Moaied,

2000), increase water use efficiency (Miranzadeh et al., 2011), contribute to darker and

thicker leaves (Tolbert, 1960; Ma & Smith, 1991), and increase post-dormancy

regeneration in winter wheat (Rademacher, 2009). Chlormequat chloride works by

inhibiting the production of gibberellins, a plant hormone involved in cell expansion and

stem elongation (Espindula et al., 2009). The activity and effect of PGRs is highly

dependent on the rate used, crop growth stage and environmental conditions (Miziniak

& Matysiak, 2016), as well as the cultivar (Espindula et al., 2009).

Previous studies conducted in western Canada have focused primarily on the

product rates, fertility rates and timing of a chlormequat chloride application (Pratchler

& Brandt, 2015; Holzapfel, 2015; Hall, 2015a). However, there is minimal information on

whether wheat cultivars exhibit similar or contrasting responses to this product.

Therefore, the purpose of this study was to evaluate and compare the effect of

chlormequat chloride on 5 cultivars of hard red spring wheat under field conditions.

3

2.0 Literature Review

2.1 Wheat Production in Saskatchewan

Wheat continues to be the principal crop grown in Saskatchewan; in 2015, it was

grown on 13.0 million of the 35.9 million acres of cropland in the province (Government

of Canada, 2015b; Government of Saskatchewan, 2016a). Saskatchewan produced over

13 million tonnes of wheat in 2015, contributing to the $125 million in crop exports from

the province (Government of Saskatchewan, 2016b). Average hard red spring wheat

yields in the RMs where the current study was located remain relatively low at

approximately 2688 kg/ha (40 bu/ac) (Government of Saskatchewan, 2016a). However,

several intensive growers that have fine-tuned their management practices and increased

their fertility have been achieving yields above 6047 kg/ha (90 bu/ac) in this region.

2.2 Breeding for Lodging Resistance

The manipulation of gibberellins in wheat production has been taking place since

the 1950’s when the ‘Green Revolution’ began. Worldwide wheat yields have increased

dramatically since that time, largely due to the introduction of semi-dwarf wheat cultivars

(Band & Bennet, 2013). Semi-dwarf wheat cultivars carry Rht mutations that make them

gibberellin-insensitive (Claeys et al., 2014). The development of nitrogen fertilizer

prompted breeders to search for wheat cultivars that were resistant to lodging so that

nitrogen fertilizer would increase seed yield, rather than increasing straw biomass or

lodging risk (Silverstone & Sun 2000). Several dwarf wheat lines were brought to the U.S.

from Japan after WWII and were introduced to commercial wheat cultivars. Late

4

flowering and partial male-sterility were issues associated with the Japanese dwarf lines,

but modifier genes were introduced to counteract the negative effects. Norman Borlaug

bred the Rht mutations into his Mexican wheat cultivars, which led to commercial semi-

dwarf wheat cultivars that were high-yielding. One of the Rht mutant alleles is present in

nearly all commercial wheat cultivars grown today (Silverstone & Sun, 2000).

2.3 Gibberellin Synthesis and Roles in Plants

Gibberellins are the plant hormone affected by chlormequat chloride (Miranzadeh

et al., 2011). Gibberellins are synthesized in several areas of the plant including

developing and germinating seeds, developing leaves, and elongating internodes (Taiz et

al., 2015). Biosynthesis begins in the plastids of cells and involves a complex pathway

involving multiple enzymatic reactions before bioactive gibberellins are produced (Figure

1). Gibberellins are transported via the vascular system (Taiz et al., 2015). Biologically

active gibberellins play a role in promoting seed germination, root growth,

photomorphogenesis, the transition to flowering, pollen development, pollen tube

growth, fruit development and most notably the promotion of cell elongation (Band &

Bennet, 2013; Taiz et al., 2015). Gibberellins stimulate cell wall relaxation by inducing the

expression of expansins and xyloglucan endotransglucosylase/endohydrolases. This leads

to cell wall changes that allow for cell expansion with increased turgor pressure (Claeys

et al., 2014). Gibberellins also promote cell expansion by influencing gene expression for

auxin biosynthesis and transport (Claeys et al., 2014). Chlormequat chloride decreases

gibberellin levels, inhibiting cell expansion and stem elongation (Band & Bennet, 2013).

5

Figure 1: Gibberellin biosynthetic pathway in plant cell (Taiz et al., 2015).

6

2.4 Plant Growth Regulators

PGRs are synthetic products that modify plant hormone balances for specific

purposes (Espindula et al., 2009). In agricultural crop production, they are most

commonly used to reduce shoot length without negatively affecting the development or

health of the plant (Rademacher, 2000). A reduction in shoot length reduces the risk of

lodging and allows the plant to allocate more energy to seed production and grain yield

(Nybo & Sluth, 2016). To achieve height reduction and stem strength, the target hormone

is typically gibberellins, which are involved in stimulating cell expansion, cell division and

stem height (Tolbert, 1960; Rademacher, 2000). Products such as ethephon that release

the plant hormone ethylene can also be used to reduce plant height, but rates and effects

may differ significantly from anti-gibberellin compounds (Rademacher, 2009).

PGRs that inhibit gibberellin synthesis can be divided into three classes, based on

the specific stage of gibberellin biosynthesis they interrupt (Figure 1). Class 1 includes

quaternary ammonium (CCC, mepiquat chloride and AMO-1618) and phosphonium

(chlorophenium chloride), which block ent-kaurene synthesis from geranylgeranyl

diphosphate. This step occurs early in gibberellin biosynthesis (Rademacher, 2009).

Chlormequat chloride specifically interrupts the activity of copalyl-diphosphate synthase

and ent-kaurene synthase. Nitrogen containing heterocyclic compounds make up the

second class, and they inhibit stage 2 of gibberellin biosynthesis when ent-kaurene is

oxidized to ent-kaurenoic acid by cytochrome P450 monooxygenases. Class 3 includes

acylcyclohexanesdiones that inhibit 2-oxoglutarate-dependent dioxygenases during stage

3 of biosynthesis (Espindula et al., 2009; Srivastava, 2002).

7

In addition to chlormequat chloride, several other PGRs are used as stem

stabilizers. Trinexapac-ethyl, paclobtrazol and prohexadione-Ca are also anti-gibberellins,

and ethephon is an ethylene-releasing compound (Espindula et al., 2009; Rademacher,

2000). These products can be used as stand-alone products, but they are more often

combined with each other in intensive European wheat production systems

(Rademacher, 2009). Trinexapac-ethyl blocks the later stages of gibberellin biosynthesis

and acts fast compared to chlormequat chloride, but does not have a long residence time

in the plant (Rademacher, 2009).

Research published in 2009 indicated that trinexapac-ethyl was slightly more

effective at reducing plant height than chlormequat chloride. However, there was a yield

reduction with the application of trinexapac-ethyl due to the reduction in biomass and

photosynthetic capability of the treated plants (Espindula et al., 2009). Trinexapac-ethyl

also requires high temperatures to work effectively, potentially limiting its capabilities in

a semi-arid climate like Saskatchewan (Rademacher, 2009). Paclobutrazol is less effective

than chlormequat chloride or trinexapac-ethyl at reducing plant height (Espindula, et al.,

2009). Timing is also more critical with this product because the molecule is not widely

mobile in the plant; only the product directly contacting the stem is translocated into the

vascular system (Styer, 2003). Prohexadione-Ca, like chlormequat chloride, also blocks

the later stages of gibberellin biosynthesis. It acts quickly in the plant like trinexapac-ethyl,

and is known to promote root growth (Rademacher, 2009).

Ethephon releases a different plant hormone, ethylene. It must be used judiciously

when there is a risk of heat or drought stress, because the combination of stress ethylene

8

and ethylene from ethephon may negatively affect seed production (Rademacher, 2009).

Ethephon may also cause stunted growth or abnormal stem thickening if application

timing is incorrect. It is more commonly used on barley and is also often mixed with other

PGRs to help mitigate potential risks associated with the product (Rademacher, 2009).

2.5 History of Chlormequat Chloride

Chlormequat chloride was the first PGR used to reduce lodging in cereal

production (Rademacher, 2009). N.E. Tolbert (1960) from Michigan State University at

East Lansing was the first scientist to describe the compound as able to reduce shoot

length in wheat and other plant species (Tolbert, 1960; Wittwer & Tolbert, 1960).

American Cyanamid held the commercial rights until BASF introduced Cycocel in 1965 as

the first anti-lodging PGR. In Canada, PGR research began in the 1980s, but their adoption

has been limited due to some products causing crop injury, narrow application windows

and low cereal prices (Pratchler, 2014). Chlormequat chloride remains the most widely

used PGR on a global scale, primarily being used in wheat, triticale and oat production

(Rademacher, 2009).

2.6 Manipulator®

The source of the chlormequat chloride product used in this experiment is sold

under the trade name Manipulator®. The distributor of Manipulator® in Canada is

EngageAgro, who began selling the product in Saskatchewan in September, 2014 (Ewen,

2015). Manipulator® contains the active ingredient chlormequat chloride (620 g ae/L),

low temperature activators and safeners (EngageAgro, 2015). It is a systemic product

9

formulated as a suspension concentrate. Manipulator® is one of the first PGRs specifically

formulated for Canadian growing conditions. Some of the key features EngageAgro

advertises is that air temperature does not affect the product, it has a wide application

window and it can be safely mixed with other agricultural chemicals that are being applied

to wheat (EngageAgro, 2015). Manipulator® is currently only registered on spring, durum

and winter wheat in Saskatchewan, but research is being done on other cereal crops as

well. At the time of this experiment, the cost of the product to growers was approximately

$35/ha ($14/ac) to apply the label rate of 174 g ae/ha (0.7 L/ac) (Bernardin, Personal

Communication, 2017).

EngageAgro recommends that the application of chlormequat chloride be done

during a specific period in the wheat crop’s life cycle. Wheat growth staging is an

important factor when working with PGRs as application at the wrong crop stage can lead

to reduced efficacy or crop damage (Miziniak & Matysiak, 2016). According to EngageAgro

(2015), the window of safe application for chlormequat chloride is from Zadoks growth

stage (ZS) 12-39, but optimal timing is between ZS 30-32, when the first node is detectable

and the main stem head is 1-3 cm above the ground (Zadoks, 1974). Best results occur at

this stage because it is when the highest amount of gibberellin is being synthesized in the

plant (Pratchler & Brandt, 2015). Figures 2 and 3 are examples of wheat plants at ZS 33,

shortly after optimal application timing for chlormequat chloride.

10

Figure 2 (left) & 3 (right): Wheat plant at ZS 33, shortly after timing of chlormequat chloride application.

This is also a key stage of development because head formation is beginning at

the base of the stem, although the effects of a PGR application on head formation are not

well documented (Rajala, 2003). Applications made before or after ZS 30-32 are safe and

effective; however, plant height and yield response may be reduced compared to

application at the optimal stage (Hall, 2015a). Early applications allow the plant time to

metabolize some of the chlormequat chloride before it can inhibit the production of

gibberellins while later applications will not reduce height as much because some of the

stem elongation has already occurred by that point (Pratchler & Brandt, 2015).

Manipulator was approved for registration by Health Canada’s Pest Management

Regulatory Agency in September, 2014. Chlormequat chloride has been used in Europe

for many years, but the U.S. Environmental Protection Agency has not established a

maximum residue limit for chlormequat chloride (Minogue, 2015). This means any grain

11

shipments exported to the U.S. cannot have any chlormequat chloride residue and

therefore, cannot have been treated with Manipulator. Growers who are considering

using Manipulator are encouraged to contact their grain buyers prior to using the product,

as many are not accepting delivery of wheat that has been treated with chlormequat

chloride (Minogue, 2015). This has limited the use of Manipulator in Saskatchewan thus

far mainly to research trials or to wheat grown for seed. Registration in the U.S. is

expected to be approved by the 2018 growing season (Bernardin, Personal

Communication, 2017).

2.7 Chlormequat Chloride Use

2.7.1 Global

PGRs are used in over 70% of intense cereal production in European countries such

as France, Germany and Great Britain (Rademacher, 2009). Lodging became a more

significant issue in these winter wheat producing areas in the 1950s and 1960s, well

before widespread lodging issues arose in areas of spring wheat production on the

Canadian prairies (Rademacher, 2009). However, not all countries allow the use of PGRs;

the Swedish government has banned the use of stem stabilizers since 1989. This was done

to lower the potential negative environmental effects of intensive agricultural

production. Wheat productivity in Sweden has remained relatively stagnant since then,

while other country’s productivity continues to increase. Germany’s wheat productivity

is now approximately 20% higher than that of Sweden’s, illustrating the benefits of stem

stabilizers in intensive European winter wheat production (Rademacher, 2009). Stem

stabilizers comprise approximately 30% of global PGR sales (Rademacher, 2010). In Great

12

Britain in 2006, anti-lodging PGRs were used on 89% of winter wheat, 76% of winter

barley, 67% of oats and 95% of rye acres (Garthwaite et al., 2006).

2.7.2 Saskatchewan

Considerable trial work has been done with chlormequat chloride across the

prairies in the past several years. Research has been done by producers, third party

organizations, EngageAgro, and government-funded research programs. The majority of

the research has been focused on determining the effect of application timing and fertility

rates on chlormequat chloride’s performance (Brandt, 2014; Holzapfel, 2015; Pratchler &

Brandt, 2015; Nybo & Sluth, 2016). Trials performed in Melfort and Indian Head in 2012

and 2013 showed that PGRs and higher fertilizer rates create the opportunity for

significantly higher yields (Brandt, 2014). Work done by Pratchler and Brandt (2015) in

Melfort, SK showed that chlormequat chloride was equally effective at reducing plant

height across several levels of fertility. Although statistically insignificant, there was a

tendency for chlormequat chloride to more effectively decrease lodging under high

fertility levels. Yield, protein, and crop maturity were unaffected in the 2015 study, but

studies in 2013 and 2014 showed bushel increases of 739 kg/ha (11 bu/ac) and 941 kg/ha

(14 bu/ac), respectively, when treated with chlormequat chloride (Pratchler & Brandt,

2015).

Trials done in Yorkton, SK also showed height reduction and a significant yield

increase of 672 kg/ha (10 bu/ac) with the application of chlormequat chloride in 2015

(Hall, 2015a). A similar yield increase was observed in Outlook, SK in 2014 in durum wheat

13

under irrigation. Chlormequat chloride application shortened plant height by 12.6 cm,

increased yield by 658 kg/ha (9.8 bu/ac), prevented lodging for one extra month, and

reduced overall lodging by 20% (Ewen, 2015). At Outlook in 2015 however, durum wheat

saw no yield response to chlormequat chloride application, while hard red spring wheat

saw a 269 kg/ha (4 bu/ac) increase in yield (Hnatowich & Ewen, 2016). Another study

with durum wheat at Swift Current in 2015 showed very little height reduction (3 cm) or

yield response (148 kg/ha; 2.2 bu/ac) when chlormequat chloride was applied at ZS 31.

The lack of response was attributed to the extremely dry conditions early in the growing

season that significantly limited lodging risk and yield potential (Nybo & Sluth, 2016).

Research done at Indian Head in 2013, 2014 and 2015 proved that mean yield

increases of 940, 670 and 540 kg/ha (14, 10 and 8 bu/ac) can be achieved when

application timing is correct and fertility levels are increased (Holzapfel, 2015). Holzapfel’s

work also showed that lodging significantly decreased with the application of a PGR, in

addition to the 12.5 cm, or 13%, reduction in plant height when averaged across N rates.

He found that grain protein decreases when treated with a PGR. Because of the higher

yield, the proteins in the seed make up a smaller percentage of the kernel. Depending on

the response to chlormequat chloride, he concluded higher N rates may be necessary to

maintain high protein levels in high yielding wheat. Test weight and thousand kernel

weights were unaffected by the application of chlormequat chloride in his fertility

response trials (Holzapfel, 2015). Another trial by Holzapfel looked at the effects of

seeding rate with a PGR application; there was no correlation between these two factors

in the yield and protein results (Holzapfel, 2016).

14

There have been few studies specifically targeting the impact of chlormequat

chloride on different cultivars of wheat typically grown in Saskatchewan. PGR application

is tailored to specific cultivars in Europe based on the cultivar’s response to certain

products and rates (Rademacher, 2009); therefore, it is reasonable to believe Canadian

hard red spring wheat cultivars will respond differently to PGR application as well. One

study done in Yorkton, SK in 2015 compared the response of AC Unity and AC Goodeve

wheat to nitrogen fertility and chlormequat chloride (Hall, 2015a). Chlormequat chloride

reduced lodging and increased yield in both cultivars, but the greatest benefit was to AC

Unity because it was more susceptible to lodging. AC Unity yield increased from 3091 to

3763 kg/ha (46 to 56 bu/ac) whereas AC Goodeve only increased from 3628 to 3964 kg/ha

(54 to 59 bu/ac) (Hall, 2015a).

Another cultivar response trial was done in 2015 at three locations in SK:

Moosomin, Redvers and Langbank. This study compared chlormequat chloride’s effect on

AAC Brandon, AC Carberry, AC Cardale, Glenn and Waskada cultivars. The taller cultivars

Glenn and AC Waskada had more consistent height reductions and yield responses

compared to the shorter cultivars AC Carberry, AC Cardale and AAC Brandon. Lodging was

not a major factor at any of the sites in this study, so the approximate yield response

across all cultivars was only 202 kg/ha (3 bu/ac) (Shaw, 2016). In research trials done at

Indian Head, the only parameter with a cultivar x PGR treatment interaction was lodging

score. Yield, height, test weight, protein and moisture content were not influenced by a

cultivar x treatment interaction (Bernardin, unpublished, 2016).

15

3.0 Research Report

3.1 Hypothesis & Objectives

This experiment was conducted to analyze hard red spring wheat cultivar

response to chlormequat chloride (Manipulator) treatment. Two factors were examined:

cultivar and chlormequat chloride treatment. It is expected that cultivars will respond

differently to chlormequat chloride treatment, indicated by a difference in at least one of

the seven parameters being measured.

3.2 Materials & Methods

Field experiments were conducted in the 2015 growing season. Test sites were in

the black soil zone of north-central Saskatchewan in the rural municipalities of Great Bend

(405), Laird (404) and Rosthern (403). The first two months were extremely dry with only

0.4 mm of precipitation in May and 13.6 mm in June. Crops relied on moisture from 18.3

mm of precipitation that fell on April 25th and 26th as well as subsoil moisture from

autumn rains in 2014. Precipitation was high for the rest of the year with 84.3 mm of rain

in July, 45.2 mm in August and 50.0 mm in September (Government of Canada, 2015a).

The experimental design was a randomized complete block conducted at field

scale. The size of the reps at each test site were equal, but strip size ranged from 0.16 to

0.77 ha (0.40 to 1.90 ac) between sites. The experiment compared one treatment to a

control for each of the wheat cultivars: chlormequat chloride applied at a rate of 174 g

ae/ha (0.7 L/ac) and no chlormequat chloride applied. Treatments for all sites were

applied at ZS 30-32 with 94 L/ha (10 USG/ac) water volumes (Figure 4 & 5). Each site

16

contained 4 replicates of each treatment in a randomized strip pattern (Figure 6). There

were 3 sites at different locations for each of the cultivars in the trial, except AC Elsa (2)

and AC Carberry (1). One of the CDC Morris sites was harvested for green feed prior to

maturity so CDC Morris results were based on 2 sites.

Figure 4 (left) & 5 (right): Chlormequat chloride application at ZS 32 on AC Harvest and AC Lillian.

UT T T UT T UT T UT

Figure 6: Randomized strip pattern of treated (T) and untreated (UT) samples at each site.

Several characteristics specific to each cultivar were relevant to this experiment.

In 2015, AC Carberry replaced AC Barrie as the cultivar used as the check for comparing

all other cultivars of hard red spring wheat in Saskatchewan (Saskatchewan Ministry of

Agriculture, 2015). AC Carberry has a 14.6% protein rating, a very good lodging score and

17

grows 84 cm tall (Government of Alberta, 2008; Saskatchewan Ministry of Agriculture,

2015). CDC Morris is a cultivar with a 14.2% protein rating and a good lodging score. It

yields 109% of the AC Carberry check in the black soil zone and is a relatively tall cultivar,

standing 10 cm taller than the AC Carberry check (Saskatchewan Ministry of Agriculture,

2015). AC Harvest is a cultivar with excellent straw strength and very good resistance to

lodging (Government of Alberta, 2008). It yields 103% of the AC Carberry check in the test

site region and has a 14.4% protein rating. It also stands 94 cm tall (Saskatchewan Ministry

of Agriculture, 2015). AC Lillian is a cultivar with a fair resistance to lodging. It is also a tall

cultivar, standing 12 cm taller than the 84 cm AC Carberry check. AC Lillian yield is 97% of

AC Carberry’s in the black soil zone and has a high protein rating of 15.7% (Saskatchewan

Ministry of Agriculture, 2015). AC Elsa is an older cultivar of hard red spring wheat with

good resistance to lodging (Government of Alberta, 2008). It has a 14.8% protein rating

and grows 92 cm tall (Saskatchewan Ministry of Agriculture, 2014).

Each cultivar was grown by a different producer, except AC Elsa and AC Carberry,

which were grown by the same producer. Management of each cultivar differed slightly,

primarily with the fertility that was applied (Appendix A, B, C, D). All cultivars in the

experiment were treated with herbicides as well as a fungicide application at anthesis (ZS

61-65), targeting fusarium head blight (Appendix A, B, C, D).

Seven parameters were used to evaluate the performance of chlormequat

chloride: yield, plant height, lodging score, protein content, moisture content, test weight

and overall grade. Yield was determined by harvesting each test strip and weighing the

grain with a certified scale on a weigh wagon. The same weigh wagon was used for all

18

sites and remained stationary when harvesting each site to limit variability. The CDC

Morris and AC Lillian cultivars were swathed prior to harvest while AC Carberry, AC Elsa

and AC Harvest were straight-cut.

Plant height was measured at full maturity, prior to harvest. Measurements were

based on main stem heads (Figure 7). Measurements were taken from several places in

each strip, and the average of those measurements was recorded. Random areas were

chosen for measurements within strips, but similar areas between strips were chosen so

that measurements were representative and could be compared as fairly as possible.

Figure 7: Unofficial plant height measurement being taken prior to maturity.

Lodging scores were determined immediately prior to harvest. A 0-9 lodging scale

was used, with 0 equating to no lodging and 9 having complete lodging. The same

individual scored all sites to remove as much subjectivity as possible. Average scores for

19

each rep were recorded. Seed protein content, moisture content, test weight and overall

grade were all determined from grain samples collected at harvest. All samples were sent

to the same commercially regulated facility for analysis (Viterra, Saskatoon). Protein

content was determined using an Infratec® 1229 Whole Grain Analyzer. Moisture tests

were done as a proxy to compare differences in maturity at harvest. Test weight (g/0.5 L)

and grade (1-3, Feed=4) were determined according to the Canadian Grain Commission’s

official grain grading guide (Canadian Grain Commission, 2015).

Statistical Analysis

Analysis of variance was conducted with SAS 9.4 using the PROC MIXED procedure,

with treatment considered a fixed effect and replications considered to be random.

Significant interactions between cultivar and treatment were further analyzed within

cultivar. PGR treated versus control treatments were compared with orthogonal

contrasts. Differences between means were separated using Tukey’s HSD0.05 (Table 1).

3.3 Results

Table 1: Statistical analysis values.

Moisture Test Weight Grade

Parameter DF F Value P Value DF F Value P Value DF F Value P Value

Cultivar 4 11.76 <.0001 4 22.04 <.0001 4 32.64 <.0001

Treatment 1 0.08 0.7823 1 1.51 0.2295 1 0.06 0.8098

Cultivar x Treatment

4 2.71 0.0441 4 0.98 0.4338 4 0.09 0.9864

Yield Height Lodging Protein

Parameter DF F Value P Value DF F Value P Value DF F Value P Value DF F Value P Value

Cultivar 4 28.97 <.0001 4 17.51 <.0001 4 14.57 <.0001 4 17.54 <.0001

Treatment 1 45 <.0001 1 354.11 <.0001 1 65.08 <.0001 1 20.05 <.0001

Cultivar x Treatment

4 1.65 0.1839 4 8.27 <.0001 4 3.42 0.0171 4 3.93 0.0089

20

Chlormequat chloride treatment had a positive influence on yield, but there was

no cultivar x PGR treatment interaction for yield (P>0.05) (Table 1). The application of

chlormequat chloride significantly increased the yield of all cultivars in this experiment

(Figure 8). The average yield increase across all cultivars was 319 kg/ha (4.8 bu/ac). AC

Carberry and AC Harvest experienced the lowest increases of 221 kg/ha (3.3 bu/ac) and

226 kg/ha (3.4 bu/ac), respectively, but these were statistically significant increases. The

highest yield increase was observed in the AC Lillian wheat, where treated samples

yielded 527 kg/ha (7.9 bu/ac) more than the untreated samples. AC Lillian also had the

highest percentage increase in yield at 12.0%. AC Elsa, CDC Morris and AC Carberry had

yield increases of 6.8%, 6.6% and 6.5%, respectively. AC Harvest yield increased by 4.0%

with chlormequat chloride application. Overall, the average of treated and untreated

samples of each cultivar ranged from AC Carberry’s 3524 kg/ha (52 bu/ac) to AC Harvest’s

5696 kg/ha (85 bu/ac) (Figure 9).

21

Figure 8: Yield comparison between chlormequat chloride-treated samples and untreated samples of all cultivars. Error bars represent the standard error of the difference between treated and untreated means. Different letters denote significant differences.

Figure 9: Yield comparisons between the mean of all samples of each cultivar. Error bars represent the standard error of the difference between treated and untreated means. Different letters denote significant differences.

a

b

3000

3300

3600

3900

4200

4500

4800

5100

Treated Untreated

All Cultivars

Yie

ld (

kg/h

a)

c

b

a

bb

0

1000

2000

3000

4000

5000

6000

AC Carberry AC Elsa AC Harvest AC Lillian CDC Morris

Yie

ld (

kg/h

a)

22

There was a cultivar x treatment interaction present in the plant height response

to chlormequat chloride treatment (P<0.05) (Table 1). All cultivars experienced a

reduction in plant height when treated with chlormequat chloride, ranging from 9 cm to

18 cm (Figure 10, 11). The average difference in plant height across all cultivars was 14

cm, a 14.9% reduction. AC Carberry and CDC Morris heights were reduced by 9 cm (11.1%

and 10.1% respectively), AC Elsa by 15 cm (15.4%), AC Lillian by 17 cm (17.2%) and AC

Harvest by 18 cm (20.4%).

Figure 10: Difference in plant height between chlormequat chloride treated and untreated samples for each cultivar. Error bars represent the standard error of the difference between treated and untreated means. Different letters denote significant differences. *Letters denote significant difference between main effects.

b*

a*

e

cd d

a

e

bc

cd

a

d

b

65

70

75

80

85

90

95

100

105

Trea

ted

Un

trea

ted

Trea

ted

Un

trea

ted

Trea

ted

Un

trea

ted

Trea

ted

Un

trea

ted

Trea

ted

Un

trea

ted

Trea

ted

Un

trea

ted

All Cultivars AC Carberry AC Elsa AC Harvest AC Lillian CDC Morris

Pla

nt

Hei

ght

(cm

)

23

Figure 11: Visual height difference between treated (left) and untreated (right) strips.

Statistical analysis revealed an interaction between cultivar and chlormequat

chloride treatment for lodging (P<0.05) (Table 1). The application of chlormequat chloride

reduced the severity of lodging for all cultivars except AC Carberry, which had no lodging

in the treated or untreated strips (Figure 12). The most severe lodging occurred on the AC

Lillian test sites (Figure 12, 13, 15). Chlormequat chloride decreased lodging severity by a

score of 2.3, but lodging was considerable even in some of the treated strips (Figure 15).

Significant lodging was visible in the untreated strips 1-2 weeks prior to lodging occurring

in the treated strips (Figure 14, 15, 16, 17). The other cultivars were subject to minor

lodging, but chlormequat chloride treatment was effective there as well, indicated by AC

Elsa’s 3.1 decrease in score, AC Harvest’s 2.9 decrease (Figure 18, 19) and CDC Morris’ 1.9

decrease (Figure 12).

24

Figure 12: Cultivar lodging score comparison between chlormequat chloride treated and untreated samples. Error bars represent the standard error of the difference between treated and untreated means. Different letters denote significant differences. *Letters denote significant difference between main effects.

Figure 13: Visible difference in AC Lillian lodging severity between chlormequat chloride treated (right) and untreated (left).

b*

a*

d d d

bc

d

bb

a

cd

b

0123456789

Trea

ted

Un

trea

ted

Trea

ted

Un

trea

ted

Trea

ted

Un

trea

ted

Trea

ted

Un

trea

ted

Trea

ted

Un

trea

ted

Trea

ted

Un

trea

ted


Lod

gin

g Sc

ore

(0

-9)

25

Figure 14 & 15: Comparison of lodging severity shortly after head emergence to full maturity prior to harvest. Both images are of the same untreated (left) and treated (right) AC Lillian strips.

Figure 16 & 17: Comparison of lodging severity shortly after head emergence to full maturity prior to harvest. Both images are of the same untreated (left) and treated (right) AC Lillian strips.

26

Figure 18: Visible difference in AC Harvest lodging severity between chlormequat chloride treated (right) and untreated (left).

Figure 19: View of AC Harvest treated (top) versus untreated (bottom) from combine cab.

27

Results for protein content indicated there was an interaction between cultivar

and chlormequat chloride treatment in this experiment (P<0.05) (Table 1). The application

of chlormequat chloride negatively affected the protein content of 3 cultivars: AC Elsa, AC

Harvest and AC Lillian (Figure 20). AC Elsa exhibited a protein content that was reduced

by 0.25%, while AC Harvest was reduced by 0.65% and AC Lillian by 0.52%. The difference

in protein between treated and untreated samples was not significant for AC Carberry

and CDC Morris.

Figure 20: Seed protein content difference between chlormequat chloride treated samples and untreated samples for each cultivar. Error bars represent the standard error of the difference between treated and untreated means. Different letters denote significant differences. *Letters denote significant difference between main effects.

Seed moisture content, test weight, and sample grade were largely unaffected by

chlormequat chloride application. Statistical analysis revealed a cultivar x treatment

interaction for moisture content (P<0.05) (Table 1), but the only cultivars with a significant

difference between treated and untreated was CDC Morris (0.2%) and AC Carberry (0.4%)

(Figure 21). Wheat head emergence in the samples treated with chlormequat chloride

b*a*

cd cde

ede

c

bb

a

c c

12

12.5

13

13.5

14

14.5

15

15.5

16

Trea

ted

Un

trea

ted

Trea

ted

Un

trea

ted

Trea

ted

Un

trea

ted

Trea

ted

Un

trea

ted

Trea

ted

Un

trea

ted

Trea

ted

Un

trea

ted


Pro

tein

Co

nte

nt

(%)

28

was approximately 2-3 days later than the untreated samples, but it did not delay harvest

for any of the cultivars. Although test weights varied between cultivars, there were no

statistically significant differences between the test weights of treated and untreated

samples for any of the cultivars. Sample grades ranged from a grade of 1 to 3, depending

on the cultivar, but there were no significant differences between treated and untreated

samples of each cultivar.

Figure 21: Difference in seed moisture content between chlormequat chloride treated and untreated samples for each cultivar. Error bars represent the standard error of the difference between treated and untreated means. Different letters denote significant differences. *Letters denote significant difference between main effects.

Based on yield increase alone, chlormequat chloride application was profitable for

all cultivars in this experiment (Table 2). With the cost of the product at $34.60/ha

($14/ac) and an estimated application cost of $12.35/ha ($5/ac) for the separate sprayer

pass, the total cost of application was approximately $46.95/ha ($19/ac) (Bernardin,

Personal Communication, 2017). At a wheat price of $0.24/kg ($6.50/bu), the cultivar with

a* a*

ab ab ab

bc abcc c

e d

10

11

12

13

14

15

16

17

Trea

ted

Un

trea

ted

Trea

ted

Un

trea

ted

Trea

ted

Un

trea

ted

Trea

ted

Un

trea

ted

Trea

ted

Un

trea

ted

Trea

ted

Un

trea

ted


See

d M

ois

ture

Co

nte

nt

(%)

29

the highest profitability was AC Lillian at $78.91/ha ($32.35/ac) and AC Carberry was

lowest at $5.83/ha ($2.45/ac) (Table 2).

Table 2: Profitability table for chlormequat chloride application.

3.4 Discussion

The results showed that it was not conclusive that chlormequat chloride impacted

yield differently between cultivars, although cultivars generally saw positive yield

responses to chlormequat chloride; the difference between treated and untreated

samples within each cultivar was significant. AC Lillian had the highest relative yield

increase at 12.0%, which would suggest it had a better response than the other cultivars

in the experiment. However, grain yield is negatively correlated with lodging (Navabi,

2006) and the AC Lillian sites had the most lodging of any of the cultivars (Figure 12),

enhancing the benefits of a PGR application. Under severe lodging, chlormequat chloride

will not prevent lodging, but it delays the onset of lodging, giving the plants more time for

normal seed filling (Figure 14, 15, 16, 17). In Outlook, Ewen (2015) also observed a

significant delay (1 month) in lodging when chlormequat chloride was applied. The high

nitrogen fertilizer rates in combination with significant late season rainfall were likely the

two most contributing factors to the severe lodging in the AC Lillian wheat (Appendix D).

Yield Increase Wheat Price

Revenue

Increase

Application

Cost Net Profit

Cultivar kg/ha bu/ac $/kg $/bu $/ha $/ac $/ha $/ac $/ha $/ac

AC Lillian 527 7.9 0.24 6.50 125.86 51.35 46.95 19.00 78.91 32.35

CDC Morris 312 4.7 0.24 6.50 74.52 30.55 46.95 19.00 27.57 11.55

AC Elsa 308 4.6 0.24 6.50 73.56 29.90 46.95 19.00 26.61 10.90

AC Harvest 226 3.4 0.24 6.50 53.98 22.10 46.95 19.00 7.03 3.10

AC Carberry 221 3.3 0.24 6.50 52.78 21.45 46.95 19.00 5.83 2.45

30

AC Lillian’s fair lodging rating could also have been a factor; the other cultivars in the trial

were all rated as good or very good for lodging resistance (Saskatchewan Ministry of

Agriculture, 2015).

Higher yields in this experiment did not seem to produce increased lodging or an

increased benefit from chlormequat chloride. For example, AC Harvest yielded the

highest, but had the lowest relative response to chlormequat chloride treatment (4%)

compared to the other cultivars (>6%). AC Harvest also exhibited comparable lodging

scores to CDC Morris and AC Elsa (Figure 12). Furthermore, CDC Morris and AC Elsa yields

were comparable to AC Lillian’s, but the relative yield response was approximately half of

AC Lillian’s. Mechanical irregularities occurred in this experiment that may have

influenced the final results, because some data points were not valid. In one case, a

portion of one of the reps at an AC Lillian site was lost and another anomaly that

happened was when the weigh wagon was not tared properly before filling with grain

from one other AC Lillian rep. Yield information for samples with inaccurate data were

omitted prior to data analysis.

A study conducted in Yorkton, SK in 2015 comparing AC Goodeve and AC Unity

cultivars also showed no statistically significant PGR x cultivar interaction (Hall, 2015a).

AC Unity yield tended to be more responsive to a chlormequat chloride application than

other cultivars, but lodging correction was also greater in the AC Unity wheat, similar to

AC Lillian’s in this experiment. A varietal response experiment done at Indian Head also

showed no cultivar x PGR interaction for yield, even though PGR application increased

yields by 13-25% (Bernardin, unpublished, 2016). Espindula et al. (2009) also noted that

31

yield of wheat cultivars varied with chlormequat chloride application. The findings of this

experiment corroborate these studies as there was a yield advantage to applying

chlormequat chloride, but the yield benefit was not dependent on cultivar (cultivar x

treatment interaction was absent).

Results showed plant height varied between treated and untreated samples for

all cultivars, but the difference depended on the cultivar. Chlormequat chloride was most

effective on AC Harvest, decreasing height by 20.4%. After AC Carberry, AC Harvest

(untreated) was the shortest cultivar in this experiment, indicating that plant height

reduction was not directly correlated with taller cultivars. AC Carberry (untreated) was

the shortest cultivar in the experiment (Saskatchewan Ministry of Agriculture, 2015), so

it is not surprising it exhibited a smaller response to chlormequat chloride treatment

based on previous research (Navabi, 2006). However, CDC Morris’ untreated plant height

was similar to AC Harvest’s. The response difference between these two cultivars of

similar height is evidence that chlormequat chloride response is cultivar dependent. In

general, taller varieties may benefit more than shorter varieties from a chlormequat

chloride application because lodging scores are positively correlated with plant height

(Navabi, 2006). However, this experiment demonstrated that chlormequat chloride

response is dependent on the cultivar in addition to plant height.

Lodging scores were influenced by a significant interaction between cultivar and

chlormequat chloride treatment even though lodging was not a major concern at most of

the sites in the experiment. The lack of lodging was unexpected, especially after the

significant late season rainfall and the high yields. Chlormequat chloride reduced lodging

32

in AC Elsa, AC Harvest and CDC Morris by 2-3 points, although lodging was minimal (Figure

12). Plant height and yield varied between these 3 cultivars, indicating that the lodging

was not directly correlated to cultivar height or yield in this experiment. This relates to

Navabi’s (2006) findings when he concluded that, in general, taller cultivars are more

susceptible to lodging, but genetic variation among the tall phenotypes exists and can

result in various levels of lodging resistance. AC Carberry, the shortest variety, had no

lodging in any of the strips, which is in agreement with previous studies that indicated

short plants are more tolerant to lodging (Kelbert et al., 2004; Keller et al., 1999). The

good or very good lodging ratings of these 4 cultivars likely contributed to the low lodging

incidence in this experiment. The results of this experiment align with findings at Indian

Head where a cultivar x PGR treatment interaction occurred as well (Bernardin,

unpublished, 2016).

Chlormequat chloride treatment decreased protein content in AC Elsa, AC Harvest

and AC Lillian, but there was no significant difference between treated and untreated

samples in AC Carberry or CDC Morris. AC Harvest was the most responsive, experiencing

a 0.65% drop in protein when treated with chlormequat chloride. AC Lillian had

significantly higher protein than the other cultivars, likely as a result of high nitrogen

fertilization (Appendix D). Pratchler (2014) and Issah (2015) also observed protein

decreases because of increased yields in chlormequat chloride-treated wheat. Lower

protein contents are usually associated with higher yields because the N required for

protein synthesis in the seed is diluted (Campbell, et al., 1977; Clarke, et al., 1990). The

significant yield increase in the treated AC Lillian samples can account for the decrease

33

observed in the protein content, but AC Harvest had a larger protein decrease with a

smaller yield increase compared with AC Lillian. All samples were analyzed in the same

commercial facility to reduce variability, but inconsistencies in sample handling or

instrument calibration may have slightly influenced the protein readings between

samples.

Previous studies in other parts of the world have indicated both increases and

decreases in protein content when chlormequat chloride is applied, depending on the

growing season (Miziniak & Matysiak, 2016). Others have concluded that chlormequat

chloride has no effect on the protein content (Pratchler & Brandt, 2015; Cacak-Pietrzak,

et al., 2006; Leszczynska & Cacak-Pietrzak, 2004). Trials at Indian Head indicated a

reduction in protein content after a chlormequat chloride application, but there was not

a PGR x cultivar interaction in that experiment (Bernardin, unpublished, 2016). Despite

contradicting outcomes of previous studies, this experiment showed that chlormequat

chloride application may decrease seed protein content, but protein response depends

on the cultivar.

The impact of chlormequat chloride on moisture, test weight and grade was not

significant. The 2-3 day visible maturity difference at heading was due to the suppression

of gibberellins, which play a key role in the transition to reproduction and flowering (Taiz,

et al., 2015). Despite the mid-season delay, the seed moisture content data from this

study did not indicate there was a maturity difference at harvest between treated and

untreated samples of any cultivar except CDC Morris and AC Carberry, which were

marginally impacted. Issah’s findings at Scott (2015) also indicated that days to maturity

34

was unaffected by chlormequat chloride application. Test weight results in this

experiment correlate with research done by Espindula et al. (2009) and Pratchler & Brandt

(2015) who observed similar test weights of chlormequat chloride treated and untreated

samples. In this experiment, the lack of response to chlormequat chloride treatment for

moisture, test weight and grade indicates that maturity and grain quality are not affected

by chlormequat chloride application.

Regarding the profitability of applying chlormequat chloride, yield is relatively

easy to quantify for calculating economic returns (Table 2), but chlormequat chloride also

provides less easily quantifiable value. The increase in harvest efficiency is very beneficial

to producers. Reduced lodging makes harvesting easier and less stressful. Mechanical

wear on machinery is reduced because the header does not have to be lowered to the

ground to pick up lodged wheat. The reduced stem height results in less plant matter

moving through the combine, allowing for increased combine speeds. One producer in

this experiment was able to increase combine speed by over 0.8 km/hr (0.5 MPH) when

harvesting wheat treated with chlormequat chloride versus untreated wheat, without

compromising grain loss. The reduction in the amount of straw potentially makes post-

harvest trash management easier for producers as well.

There are several drawbacks that may be associated with a PGR application. The

ideal timing for application (ZS 30-32) does not align with traditional herbicide or

fungicide application timings, requiring an additional sprayer pass on the crop. Applying

the label rate of 174 g ae/ha (0.7 L/ac) requires a significant amount of product volume

to be transported and loaded into sprayers, and may reduce time efficiencies. Protein

35

decreases potentially caused by chlormequat chloride are also undesirable. Lastly, yield

benefits observed in this experiment are not guaranteed as chlormequat chloride efficacy

may be affected by environmental conditions, fertility rates, management strategies,

application timing and cultivar. Extensive measures were taken to limit the number of

variables in this field experiment, but these sources of error may have affected the results

in this experiment because of the different sites and management regimes for the

cultivars. It is unlikely for the use of chlormequat chloride to be profitable in all areas of

Saskatchewan, but there is a significant number of intensive production systems that are

achieving high wheat yields where lodging is a higher risk and chlormequat chloride would

provide significant agronomic and economic benefits.

Additional studies should be done in western Canada to evaluate chlormequat

chloride’s performance on different cultivars of wheat. Furthermore, because optimal

application timing (ZS 30-32) for chlormequat chloride is at a crucial growth stage (head

formation), research into the effect PGRs have on the number of spikelets per head and

kernels per head would provide further insight into the comprehensive effects of PGR

applications (Rajala, 2003).

36

4.0 Conclusion

Response to chlormequat chloride varied depending on the wheat cultivar,

confirming the hypothesis. Cultivar x chlormequat chloride treatment interactions were

observed for plant height, lodging severity, protein content and seed moisture content.

Yield increases were observed in all cultivars when chlormequat chloride was applied, but

the interaction between cultivar and PGR treatment was not significant for yield. All

cultivars experienced height reductions and lodging score reductions when chlormequat

chloride was applied. Lodging response appeared to be primarily dependent on PGR

application rather than plant height or yield. Chlormequat chloride reduced protein

content of 3 cultivars by varying degrees, and was non-influential for the other 2 cultivars.

Moisture, test weight and grade were largely unaffected by chlormequat chloride

application. The application of chlormequat chloride provided a profitable return for all

cultivars in this experiment, with AC Lillian benefiting the most. According to the results

of this experiment, producers should expect yield increases, plant height reductions,

increased lodging resistance and possibly protein content reductions when applying

chlormequat chloride to hard red spring wheat. Chlormequat chloride applications will be

most advantageous in intensive wheat production systems when the risk of lodging is high

and a more chlormequat chloride-responsive cultivar is grown.

37

References

Band, L., & Bennet, M. (2013). Mapping the site of action of the Green Revolution

hormone Gibberellin. Proceedings of the national academy of sciences of the

United States of America, 110(12), 4443-4444.

Bernardin, P. (2016). Overall F-test results for PGR and variety effects on selected

response variables for wheat at Indian Head. Indian Head, SK: Unpublished.

Bernardin, P. (2017, January 10). Personal Communication. (A. Reddekopp, Interviewer)

Brandt, S. (2014). Enhancing Yield of Wheat and Oat. Melfort, SK: Northeast Agriculture

Research Foundation.

Cacak-Pietrzak, G., & al, e. (2006). Effect of some retardants on baking quality of winter

wheat. Progress in Plant Protection, 46(2), 89-92.

Campbell, C., Cameron, D., Nicholaichuk, W., & H, D. (1977). Effect of fertilizer N and soil

moisture on growth, N content, and moisture use by spring wheat. Can. J. Soil

Sci., 57, 289-310.

Canadian Grain Commission. (2015). Official Grain Grading Guide. Winnipeg:

Government of Canada.

Claeys, H., De Bodt, S., & Inze, D. (2014). Gibberellins and DELLAs: central nodes in

growth regulatory network. Trends in Pland Science, 19(4), 231-239.

Clarke, J., Campbell, C., Cutforth, H., Depauw, R., & Wilkleman, G. (1990). Nitrogen and

phosphorous uptake, translocation and utilization efficiency of wheat in relation

to environment and cultivar yield and protein levels. Can. J. Plant Sci., 70, 965-

977.

DePauw, R., & al., e. (2011). Carberry hard red spring wheat. Can. J. Plant Sci., 91(3),

529-534.

DePauw, R., & et, a. (2005). Lillian hard red spring wheat. Can. J. Plant Sci., 85(2), 397-

401.

Emam, Y., & G.R., M. (2000). Effect of Planting Density and Chlormequat Chloride on

Morphological and Physiological Characteristics of Winter Barley Cultivar Valfajr.

J. Agric. Sci. Tech. , 2, 75-83.

EngageAgro. (2015, February 18). Manipulator Label. Retrieved from EngageAgro:

https://www.engageagro.com/productdtl.html?pid=59

Espindula, M., Rocha, V., Grossi, J., Souza, M., Souza, L., & Favarato, L. (2009). Use of

Growth Retardants in Wheat. Planta Daninha, 27(2), 379-387.

38

Ewen, J. (2015). Field Demosntration of Plant Growth Regulator Application on Irrigated

Wheat Production. Outlook, SK: Irrigation Crop Diversification Corporation.

Garthwaite, G., Thomas, M., Heywood, E., & Battersby, A. (2006). Pesticide usage survey

report No. 213. Retrieved from Arable Crops in Great Britain:

http://www.fera.defra.gov.uk/plants/pesticideUsage/arable2006.pdf

Government of Alberta. (2008, January 16). Harvest Hard Red Spring Wheat. Retrieved

from Alberta Agriculture and Forestry:

http://www.agric.gov.ab.ca/app95/loadCropVariety?action=display&id=618

Government of Canada. (2015a). Daily Data Report. Retrieved from Historical Data:

http://climate.weather.gc.ca/climate_data/daily_data_e.html?hlyRange=2008-

12-02%7C2017-01-13&dlyRange=2008-12-02%7C2017-01-

13&mlyRange=%7C&StationID=47707&Prov=SK&urlExtension=_e.html&searchT

ype=stnName&optLimit=specDate&StartYear=1840&EndYear=2017&selRow

Government of Canada. (2015b). Principal field crop areas. Retrieved from Statistics

Canada: http://www.statcan.gc.ca/daily-quotidien/150630/dq150630b-eng.htm

Government of Saskatchewan. (2016a). 2015 Saskatchewan Crop District Crop

Production. Retrieved from Saskatchewan Ministry of Agriculture:

http://publications.gov.sk.ca/documents/20/93048-

2015%20Saskatchewan%20Crop%20District%20Crop%20Production.pdf

Government of Saskatchewan. (2016b). Agriculture Statistics Fact Sheet. Regina, SK:

Saskatchewan Ministry of Agriculture.

Hall, M. (2015a). Impact of Manipulator on Varieties with Differeing Lodging Resistance

at High Rates of N Fertility. Yorkton, SK: East Central Research

Foundation/Parkland College.

Hall, M. (2015b). Impact of Manipulator Timing and N Fertility on Wheat Lodging and

Yield. Yorkton, SK: East Central Research Foundation/Parkland College.

Hnatowich, G., & Ewen, J. (2016). Demonstration of Plant Growth Regulator Application

on Irrigated Wheat Production. Outlook, SK: Irrigation Crop Diversification

Corporation.

Holzapfel, C. (2016). Optimal Seeding Rates for Wheat with and without Plant Growth

Regulators . Indian Head, SK: Indian Head Agricultural Research Foundation.

Holzapfel, C. (2015). Optimal Nitrogen Rates for Wheat with and without Plant Growth

Regulators . Indian Head, SK: Indian Head Agricultural Research Foundation.

39

Issah, G. (2015). Optimal Seeding Rate with Plant Growth Regulators and Fungicides for

Spring Wheat. Scott, SK: Western Applied Research Corporation.

Kelbert, A., Spaner, D., Briggs, K., & J, K. (2004). Screening for lodging resistance in

spring wheat breeding programmes. Plant Breed., 123, 349-354.

Keller, M. e. (1999). Quantitative trait loci for lodging resistance in a segregating wheat x

spelt population. Theor. Appl. Genet., 98, 1171-1182.

Leszczynska, D., & Cacak-Pietrzak, G. (2004). Influence of retardants on yields and some

quality characters of winter wheat. Electronic Journal of Polish Agricultural

Universities, 7(2), 1-11.

Ma, B., & Smith, D. (1991). Apical Development of Spring Barley in Relation to

Chlormequat and Ethephon. Agronomy Journal, 83(2), 270-274.

Minogue, L. (2015, May 15). Call your grain buyer before applying Manipulator.

Retrieved from AgCanada.com: http://www.agcanada.com/daily/minogue-call-

your-grain-buyer-before-applying-manipulator

Miranzadeh, H., Emam, Y., Pilesjo, P., & Seyyedi, H. (2011). Water Use Efficiency of Four

Dryland Wheat Cultivars under Different Levels of Nitrogen Fertilization. J. Agr.

Sci. Tech., 13, 834-854.

Miziniak, W., & Matysiak, K. (2016). Two tank-mix adjuvants effect on yield and quality

attributes of wheat treated with growth retardants. Crop Production, 46(9),

1559-1565.

Navabi, A. e. (2006). The relationship between lodging and plant height in a diverse

wheat population. Canadian Journal of Plant Science, 86(3), 723-726.

Nybo, B., & Sluth, D. (2016). Plant Growth Regulators and N Rates in Durum Wheat.

Swift Current, SK: Wheatland Conservation Area Inc.

Pratchler, J. (2014). Plant Growth Regulators in Spring Wheat. Melfort, SK: Northeast

Agriculture Research Foundation.

Pratchler, J., & Brandt, S. (2015). Engage Agro Manipulator Timing and Fertility Levels in

Spring Wheat. Melfort, SK: Northeast Agriculture Research Foundation.

Rademacher, W. (2000). Growth Retardants: Effects on Gibberellin Biosynthesis and

Other Metabolic Pathways. Annu. Rev. Plant Physiol. Plant Mol. Biol., 51, 501-

531.

Rademacher, W. (2009). Control of lodging in intense european cereal production. 2009

Conference Proceedings (pp. 61-69). Alexandria, VA: Plant Growth Regulation

Society of America. Retrieved from

40

http://www.pgrsa.org/sites/default/files/presentations/CONTROL-OF-LODGING-

IN-INTENSE-EUROPEAN-CEREAL-PRODUCTION.pdf

Rademacher, W. (2010). Dealing with plant bioregulators: An industrial view.

Proceedings of the 11th International Symposium on Plant Bioregulators in Fruit

Production (pp. 209-263). Bologna, Italy: Acta Hort.

Rajala, A. (2003). Plant Growth Regulators to Manipulate Cereal Growth in Northern

Growing Conditions. University of Helsinki, Department of Applied Biology,

Section of Crop Husbandry. Helsinki: University of Helsinki.

Saskatchewan Ministry of Agriculture. (2014). Varieties of Grain Crops. Saskatoon: The

Western Producer.

Saskatchewan Ministry of Agriculture. (2015). Varieties of Grain Crops. Saskatoon: The

Western Producer.

Saskatchewan, G. o. (n.d.).

Shaw, L. (2016). Comparison of Manipulator Growth Regulator in Four Varieties of

Wheat. South East Research Farm.

Shaw, L. (2016). Comparison of Manipulator Growth Regulator in Four Varieties of

Wheat. Redvers, SK: South East Research Farm.

Shekoofa, A., & Emam, Y. (2008). Effects of Nitrogen Fertilization and Plant Growth

Regulators (PGRs) on Yield of Wheat (Triticum aestivum L. cv. Shiraz). Journal of

Agricultural Science and Technology, 10(2), 101-108.

Silverstone, A., & Sun, T. (2000). Gibberellins and the Green Revolution. Trends in Plant

Science, 5(1), 1-2.

Srivastava, L. (2002). Plant growth and development. San Diego: Academic Press.

Styer, R. (2003, March 30). Maximizing Chemical Growth Retardants. Retrieved from

Greenhouse Product News: http://www.gpnmag.com/article/maximizing-

chemical-growth-retardants/

Taiz, L., Zeiger, E., Moller, I., & Murphy, A. (2015). Plant Physiology and Development.

Sunderland: Sinauer Associates, Inc.

Tolbert, N. (1960). (2-Chloroethyl)trimehtylammonium Chloride and Related

Compounds as Plant Growth Substances. The Journal of Biological Chemistry,

235(2), 475-479.

41

Wittwer, S., & Tolbert, N. (1960). (2-chloroethyl) trimethylammonium chloride and

related compounds as plant growth substances .3. Effect on growth and

flowering of the tomato. American Journal of Botany, 47(7), 560-565.

Zadoks, J., Chang, T., & Konzak, F. (1974). A Decimal Code for Growth Stages of Cereals.

Weed Res. 14: 415-421.

42

Appendix A: AC Harvest Field Management Information

Nic Wiens

Field Name North of Home Yard Walter Home Qtr Lorne Home (W of Cemetary)

Land Location SW 31-42-5-W3rd NW 10-42-6-W3rd SW 2-43-6-W3rd

Variety AC Harvest AC Harvest AC Harvest

Seeding Date May 8/2015 May 13/2015 May 11/2015

Seeding Rate (lbs/ac) 156 156 156

Seed Treatment None None None

Seed Nutrient None None None

Fertility: (N-P-K-S) (lbs/ac) Floating- NH3 Spring or Fall- Liquid- Dry-

130-50-30-20 total applied at seeding. 65lbs of N applied as NH3, rest is dry.



Foliar Fertility: Liquid fert- Releaf- 42PHI- Micros- Other

2L/ac Releaf Canola applied with herbicide. 0.5L/ac 42Phi & 0.5L/ac CopRon applied with fungicide.



Herbicide type Prestige/Everest Prestige/Everest Prestige/Everest

Fungicide type Caramba/Twinline Caramba/Twinline Caramba/Twinline

Manipulator: Spray Date Water Rate

June 22/15 10 USG/ac



Pre-harvest Spray (Yes/No)

No No No

Swath Date Straight Cut Straight Cut Straight Cut

Harvest Date September 2/15 September 11/15 September 20/15

43

Appendix B: AC Carberry & AC Elsa Field Management Information

Wayne Andres

Field Name 27 71 North 71 South

Land Location SW 24 41 6 W3 SE 35 41 6 W3 SE 35 41 6 W3

Variety AC Carberry AC Elsa AC Elsa

Seeding Date May 22 May 14 May 14


Seed Treatment Raxil Raxil Raxil

Seed Nutrient


76-23-5-19 25-23-5-19 +NH3 Fall’14@ 70#N

16-23-5-19 +NH3 Fall’14@ 70#N


Herbicide type Velocity Velocity Velocity

Fungicide type Prosaro Prosaro Prosaro



June 26 10 USG/ac



Yes Yes Yes

Swath Date


44

Appendix C: Morris Field Management Information

Feitsma Grain

Field Name Monument Opa Elmer Highway 312

Land Location SE29-40-4-W3 NE5-43-3-W3 SW6-43A-3-W3

Variety CDC Morris CDC Morris CDC Morris



Seed Treatment Raxil Pro Raxil Pro Raxil Pro

Seed Nutrient


85-25-12-5

85-25-12-5

85-25-12-5


Lorsban (midge)

Lorsban (midge)

Lorsban (midge)

Herbicide type Prestige/Sierra Prestige/Sierra Prestige/Sierra







No No No

Swath Date August 20 August 22

Harvest Date September 1/15 September 4/15 Silaged - July

45

Appendix D: AC Lillian Field Management Information

Myland Farms Inc.

Field Name Mageira West Mageira East Elsie

Land Location SE12-42-8-W3 SW7-42-7-W3 NW8-42-7-W3

Variety AC Lillian AC Lillian AC Lillian



Seed Treatment Raxil Pro Raxil Pro Raxil Pro

Seed Nutrient


130-35-10-13

130-35-10-13

110-35-10-13


Releaf WA – 1L/ac Lorsban (midge)



Herbicide type Velocity Velocity Velocity







No No No

Swath Date August 21/15 August 21/15 August 21/15


Documents

Wheat (Triticum aestivum) cultivar response to … · crops, but the integration of plant growth regulators (PGRs) into intensive wheat production systems has also contributed to