Western Canadian Spring Wheat Research Articles

Competitive ability of western Canadian spring wheat cultivars in a model weed system

Economic and social pressures are spurring the study of alternate weed management strategies such as the development of competitive crop cultivars, capable of being used under an integrated management plan. The primary objective of this research was to determine whether western Canadian spring wheat ( Triticum spp.) cultivars differ in their ability to compete against model weeds and whether those differences were expressed when challenged with wild weeds. A total of 71 wheat cultivars were grown in the absence or presence of simulated [cultivated oat ( Avena sativa L.) and oriental mustard ( Brassica juncea L.)] or natural [wild oat ( Avena fatua L.)] weed competition conditions. Significant ( p = 0.01) weed by cultivar interactions involving changes in yield cultivar rank were detected, indicating that the cultivars responded differently to competition. A small minority of cultivars such as Glenlea, CDC Rama, Genesis, AC Taber, AC Vista, Plenty, Napoleon, and BW652 had high-yield potential coupled with yield maintenance under weed pressure. The competitive ability advantage appeared to be associated with plant height or tillers per square meter as well as shorter vernalization requirement combined with photoperiod sensitivity. These outlier cultivar differences could be exploited in breeding new widely adapted varieties for scenarios where reduced herbicide weed control is desired, including situations where herbicide resistance limits chemical options. Cultivars with differing competitive ability under model weed conditions maintained their ranking when challenged by natural weed infestations. This suggests that selecting competitive spring wheat cultivars using a repeatable protocol based on model weeds is realistic.

Genetic characterization of type II Fusarium head blight resistance derived from transgressive segregation in a cross between Eastern and Western Canadian spring wheat

Fusarium head blight (FHB) caused by Fusarium graminearum is a devastating disease affecting global wheat production, causing significant losses to yield and grain quality. The Eastern Canadian line FL62R1 was developed using a systemic breeding approach and boasts high levels of FHB resistance with good yield, desirable agronomics, and end-use quality traits. The objective of this study was to identify genetic determinants of type II resistance in a cross between FL62R1 and cv. Stettler, a Canada Western Red Spring variety rated moderately susceptible to FHB. Although neither parent displayed strong resistance to FHB spread within spikes following point inoculation (type II resistance) in greenhouses, strong type II resistance was observed in a large number of progeny, including 6% with resistance comparable to the best check line, Sumai 3. Quantitative trait locus (QTL) mapping identified a locus from chromosome 2BL of Stettler which provides Sumai 3 level type II resistance when combined with favorable FHB resistance QTLs with minor effects from FL62R1. This study provides insight into transgressive segregation for FHB, which despite its importance is poorly understood, rare, and difficult to predict. It also begins to dissect the genetic architecture of FHB resistance in wheat derived from the systemic breeding approach.

Allelic variation and effects of 16 candidate genes on disease resistance in western Canadian spring wheat cultivars

Recently, we mapped genomic regions associated with resistance to wheat diseases and insensitivity to Pyrenophora tritici-repentis (Ptr) toxins using 81 historical and modern Canadian western spring wheat cultivars genotyped with genome-wide single nucleotide polymorphic (SNP) markers. Here, we investigate the frequency and effects of allelic variants of 50 markers associated with 16 candidate genes that regulate resistance to leaf rust (Puccinia triticina), yellow or stripe rust (P. striiformis f. sp. tritici), tan spot (P. tritici-repentis), and Ptr ToxA reaction in a subset of 70 of the 81 spring wheat cultivars. We evaluated the 70 cultivars in the field for all diseases except Ptr ToxA, which was evaluated in a greenhouse. Using Spearman rank correlation, stepwise discriminant analysis, and partial least squares regression, we identified between 4 and 11 markers as best predictors of each phenotypic trait. Overall, 23 of the 50 markers were associated with one or more of the phenotypic traits of which analysis of variance showed significant differences between allelic variants of 19 markers. In most analyses, markers for Lr34/Yr18 and Tsn1 loci were identified consistently as the best predictor of disease resistance and Ptr ToxA sensitivity, respectively. The same alleles from two Lr34/Yr18 diagnostic SNP markers (wMAS000003 and wMAS000004) not only decreased stripe rust scores up to 1.6 (on a 1 to 9 scale), but also increased grain yield up to 196 kg ha−1 without affecting maturity. Results from this study could aid spring wheat breeders in selecting the best parental combinations and/or marker-assisted selection to integrate disease resistance with early maturity and short stature.

Genetic variation for flowering time and height reducing genes and important traits in western Canadian spring wheat

Genetic variation is prerequisite for wheat improvement. High grain yield and protein content and early maturity are some of the major objectives in global as well as Canadian wheat breeding programs. We investigated genetic diversity for earliness related and plant height reducing (Rht) genes in 82 spring wheat cultivars, registered in western Canada, through eight diagnostic DNA markers. Allelic variation was observed at the Vrn-A1, Vrn-B1, Vrn-D1 and Ppd-D1 loci but not at Ppd-A1 and Ppd-B1 loci in the 82 cultivars. Spring type allele of Vrn-A1 was present in 94 % cultivars, whereas only two cultivars carried spring allele of Vrn-D1. Among the four earliness related genes, the most frequent combination was Vrn-A1a, Vrn-B1, vrn-D1 and Ppd-D1b, which was found in 32 cultivars. As for the Rht genes, eight cultivars had Rht-B1b and 13 cultivars had Rht-D1b. All cultivars carrying dominant allele of Vrn-B1, photoperiod-insensitive allele of Ppd-D1 and height reducing allele of Rht-1 had shorter plants and higher grain yield but lower grain protein content. Days to heading and maturity showed positive genetic (rg = 0.65) and phenotypic (rp = 0.44) correlation, and were also positively correlated with grain yield and kernel weight but negatively correlated with test weight and protein content. Plant height was positively correlated with grain protein content (rg = 0.53; rp = 0.42), but negatively correlated with grain yield (rg = −0.47; rp = −0.14). Grain yield and protein content showed negative genetic correlation (rg = −0.57). Among the sixty cultivars from Canada Western Red Spring Class released over 100 years, the newest cultivar yielded 23 % more grain and had 15 % higher grain protein than the oldest cultivar ‘Red Fife’. Breeders in western Canada have incorporated vernalization and photoperiod insensitive and Rht genes in modern cultivars to promote early maturity, to make use of off-season nurseries abroad, and to improve lodging tolerance.

Rates of yield gain of hard red spring wheat in western Canada

Thomas, J. B. and Graf, R. J. 2014. Rates of yield gain of hard red spring wheat in western Canada. Can. J. Plant Sci. 94: 1–13. The Manitoba and Saskatchewan Seed Guides dating back to 1972 represent an unused source of yield comparisons to re-examine current progress in western Canadian spring wheat cultivar yields. Adjusting for the shift in check cultivars over time showed that the yield rise due to new cultivars could be divided into two periods. Prior to the early 1990s, yields rose at a rate of about 0.33% per year; these low early rates agree with other published estimates from this period and were possibly influenced by a strong emphasis on replicating the quality of previous cultivars. From the early 1990s to 2013, yields rose by about 0.7% per year; this doubling of the earlier rate was significant based on the non-overlap of confidence intervals of comparable slopes. To compare rates published in the literature with these new rates, all slopes were adjusted to a common benchmark where mean yield = 100%. Following these adjustments, current rates in western Canada (about 0.67% per year) were comparable with a world average estimated to be about 0.62% per year. Variation in performance among Canada Western Red Spring cultivars based on the Seed Guides was significantly correlated with their on-farm yields based on Manitoba Management Plus Program (MMPP) crop insurance data (r = 0.81, n = 42). Beginning in 1991, on-farm yields rose by an average of about 1.4% per year both in Manitoba (Manitoba Management Plus Program data) and across the entire western wheat area (Statistics Canada data). This compares favorably with a world-wide rate of yield increase for wheat since 1991 of 1.16% per year. Although western Canadian on-farm yield gains were attributed to a combination of new cultivars and upgraded agronomy, the two influences were not separable in the Manitoba crop insurance data set. Opinions published in the farming press that rates of yield gain among western Canadian wheat cultivars are comparatively low were not supported by the evidence presented here.

Rates of yield gain of hard red spring wheat in western Canada

Thomas, J. B. and Graf, R. J. 2014. Rates of yield gain of hard red spring wheat in western Canada. Can. J. Plant Sci. 94: 1-13. The Manitoba and Saskatchewan Seed Guides dating back to 1972 represent an unused source of yield comparisons to re-examine current progress in western Canadian spring wheat cultivar yields. Adjusting for the shift in check cultivars over time showed that the yield rise due to new cultivars could be divided into two periods. Prior to the early 1990s, yields rose at a rate of about 0.33% per year; these low early rates agree with other published estimates from this period and were possibly influenced by a strong emphasis on replicating the quality of previous cultivars. From the early 1990s to 2013, yields rose by about 0.7% per year; this doubling of the earlier rate was significant based on the non-overlap of confidence intervals of comparable slopes. To compare rates published in the literature with these new rates, all slopes were adjusted to a common benchmark where mean yie...

Stripe rust resistance among western Canadian spring wheat and triticale varieties

Randhawa, H., Puchalski, B. J., Frick, M., Goyal, A., Despins, T., Graf, R. J., Laroche, A. and Gaudet, D. A. 2012. Stripe rust resistance among western Canadian spring wheat and triticale varieties. Can. J. Plant Sci. 92: 713–722. Stripe rust (Puccinia striiformis Westend.) is an important pathogen of wheat in western Canada and worldwide. One hundred and four spring wheat and triticale varieties and cultivars were evaluated for resistance to stripe rust in nurseries at Lethbridge and Creston, BC, during 2009 and 2010. In the Canada Prairie Spring Red (CPSR) wheat class, newer varieties were more resistant compared with many of the older varieties. Among the white Canada Prairie Spring White (CPSW) wheats, Vista was moderately resistant, whereas Snowhite475 and Snowhite476 were susceptible. Little useful resistance was observed within the Canada Western Hard White Spring (CWHWS) class. Sixty percent of the Canada Western Red Spring (CWRS) wheats, including the currently popular varieties Lillian, Harvest and Kane, were resistant. Susceptible CWRS varieties that are extensively seeded in western Canada include AC Barrie, Superb and McKenzie, but also include the recently registered CDC Kernen and Vesper. The varieties were tested for the presence of the stripe rust genes Yr10, Yr17, Yr18 and Yr36 using molecular markers. Much of the stripe rust resistance, particularly in the CWRS, Canada Western Extra Strong (CWES), and CPSR wheat classes was attributed to the presence of adult plant resistance gene Yr18. Yr17 and Yr36 were also detected among CWRS and CWES varieties. However, the absence of markers for known genes in several resistant varieties indicated that uncharacterized genes for stripe rust occur among hexaploid wheats. Durum wheat and triticale varieties were universally resistant with the absence of tested markers. Therefore, there appear to be numerous sources of stripe rust resistance, both characterized and uncharacterized, among western Canadian spring wheat and triticale varieties.

Leaf photosynthetic properties and biomass accumulation of selected western Canadian spring wheat cultivars

Chytyk, C. J., Hucl, P. J. and Gray, G. R. 2011. Leaf photosynthetic properties and biomass accumulation of selected western Canadian spring wheat cultivars. Can. J. Plant Sci. 91: 305–314. Current studies indicate wheat straw as a viable source for the production of cellulosic ethanol. Since photosynthetic performance impacts the overall success of the mature plant, this study aimed to measure the photosynthetic vigour of 11 spring wheat cultivars during field development as well as their biomass composition at maturity to determine which would be optimum for ethanol production. All cultivars had similar maximal quantum yields of photosystem II photochemistry (FV/FM), normalized difference vegetation index and biomass composition in the field. However, differences were observed in photosynthetic rate, with McKenzie having the highest light-saturated maximal rate of CO2 uptake (A max) and apparent quantum yield of CO2 uptake (Φapp CO2), while also having the best water use efficiency. Snowbird was found to have the lowest CO2-compensation point (Γ*) and A max. Upon subjecting wheat samples to photoinhibitory conditions, McKenzie and Kyle were found to be the most resistant and susceptible, respectively, with a difference of 11% in FV/FM. Abundance of xanthophyll pigments were not found to be a contributing cause to differential photoinhibitory resistance as there was not a noticeable difference between cultivars. Although some cultivars were found to have enhanced photosynthetic traits over others, these were slight and did not contribute to changes in plant biomass. However, McKenzie did present a higher cellulose content, which would be favourable for ethanol production.

Phenolic Content and Antioxidant Properties of Bran in 51 Wheat Cultivars

ABSTRACTWhole‐grain‐based diets have been suggested to reduce the incidence of cardiovascular disease and colon cancer. Phenolic compounds, most of which are present in the wheat bran, may be one of the factors contributing to whole‐grain health benefits. We measured the free, bound, and total phenolic content and antioxidant activity in the bran of 51 wheat cultivars belonging to eight Western Canadian spring wheat market classes grown in a replicated trial at Saskatoon, Saskatchewan, Canada. The free phenolic (extracted with 80% v/v aqueous ethanol) content ranged from 854.1 ± 265.1 to 1,754.9 ± 240.3 μg/g of bran gallic acid equivalent (GAE). Saponification followed by a liquid‐liquid solvent extraction released bound phenols ranging from 2,304.9 ± 483.0 to 5,386.1 ± 927.5 μg/g of bran GAE, contributing 66–82% of the total wheat bran phenolic content. Total phenolic content ranged from 3,406.4 ± 32.3 to 6,702.7 ± 19.6 μg/g of bran GAE, with the average being 5,197.2 ± 804.9 μg/g of bran GAE. Antioxidant activity ranged from 11.86 ± 2.59 to 20.12 ± 0.51%, while the overall average was 15.6 ± 2.2%. Based on varietal means, antioxidant activity correlated with free, bound, and total phenolic content (r = 0.8, P < 0.05).

Genotypic and environmental variation in grain, flour, dough and bread-making characteristics of Western Canadian Spring Wheat

Wheat (Triticum aestivum L.) grain, flour, dough and bread quality characteristics are strongly influencedby growing-season weather conditions. Understanding the impact of genotype, environment, and their interactions on Canadian wheat quality is important for Canada to maintain its high standard for delivery of consistent quality wheat to domestic and international customers. The effects of genotype, environment and genotype by environment (G × E) interaction on numerous grain, flour, dough and bread-making characteristics were assessed. The Canadian Western Red Spring (CWRS) cultivars were AC Barrie, Superb, AC Elsa, and Neepawa; the Canadian Prairie Spring (CPS-white) cultivar was AC Vista; and the Canadian Western Hard White Spring (CWHWS) cultivar was Snowbird. These genotypes were grown at five locations across the Canadian prairies in 2 yr to provide a total of 7 site-years of milling quality wheat for analysis. Genotype, environment and their interactions had significant effects on most parameters tested. The relative magnitude of the environmental contribution to wheat quality variance, depending on the trait, was considerably larger (14 to 89%) than the variance contribution of either genotype (0 to 33%) or G × E interaction (0 to 17%). The greatest environmental contribution to total variance (83%) was, on average, for grain traits including yield. Genotypic contribution to variation was greatest (~15%) for flour characteristics. The G × E interaction contributed relatively little to total variance and was comparable for flour, dough and bread properties (~6.5% on average). This large difference in variance between environmental and genotypic influences clearly demonstrates the importance of growing-season weather impacts on yield and quality for adapted bread wheat genotypes and strategies to mitigate these effects are discussed. Key words: Wheat, bread-making quality, Canadian prairies, environment, genotype, genotype by environment

Molecular characterization of vernalization response genes in Canadian spring wheat

Vernalization response (Vrn) genes play a major role in determining the flowering/maturity times of spring-sown wheat. We characterized a representative set of 40 western Canadian adapted spring wheat cultivars/lines for 3 Vrn loci. The 40 genotypes were screened, along with 4 genotypes of known Vrn genes, using previously published genome-specific polymerase chain reaction primers designed for detecting the presence or absence of dominant or recessive alleles of the major Vrn loci: Vrn-A1, Vrn-B1, and Vrn-D1. The dominant promoter duplication allele Vrn-A1a was present in 34 of 40 cultivars/lines, whereas the promoter deletion allele Vrn-A1b was present in only 1 of the western Canadian cultivars (Triticum aestivum L. 'Rescue') and 2 of its derivative chromosomal substitution lines. The intron deletion allele Vrn-A1c was not present in any line tested. Only 4 of the western Canadian spring wheat cultivars tested here carry the recessive vrn-A1 allele. The dominant allele of Vrn-B1 was detected in 20 cultivars/lines. Fourteen cultivars/lines had dominant alleles of Vrn-A1a and Vrn-B1 in combination. All cultivars/lines carried the recessive allele for Vrn-D1. The predominance of the dominant allele Vrn-A1a in Canadian spring wheat appears to be due to the allele's vernalization insensitivity, which confers earliness under nonvernalizing growing conditions. Wheat breeders in western Canada have incorporated the Vrn-A1a allele into spring wheats mainly by selecting for early genotypes for a short growing season, thereby avoiding early and late season frosts. For the development of early maturing cultivars with high yield potential, different combinations of Vrn alleles may be incorporated into spring wheat breeding programs in western Canada.

The Effect of Vernalization Genes on Earliness and Related Agronomic Traits of Spring Wheat in Northern Growing Regions

Vernalization response (Vrn) genes play a major role in determining the fl owering times of springsown wheat (Triticum aestivum L.). The objective of this study was to investigate the effect of Vrn genes on fl owering and maturity times and important agronomic traits in a set of reciprocal whole-chromosome substitution lines and eight western Canadian spring wheat cultivars of known Vrn genes, grown over three seeding dates in Alberta, Canada over 2 yr. The genotype carrying spring habit alleles at Vrn-A1, Vrn-B1, and VrnD5 fl owered and matured the earliest, and had the highest grain protein content but the lowest grain yield. Genotypes with spring habit alleles Vrn-A1 and Vrn-B1 were early maturing and high yielding. Genotypes with the spring habit Vrn-D5 allele either singly or in combination with Vrn-A1 were late maturing. The spring habit allele of VrnA1 was not completely epistatic to Vrn-B1 and Vrn-D5 for fl owering or maturity time. The spring habit allele of Vrn-B1, however, was epistatic to that of Vrn-D5 for these traits. In northern wheat growing regions, breeding preference should be given to Vrn genotypes with three spring habit alleles or those with spring habit alleles of VrnA1 and Vrn-B1. Genotypes carrying spring habit Vrn-D5 allele singly or in combination with Vrn-A1 should be planted as early in the growing season as possible to realize their full yield potential.

Reactions of western Canadian spring wheat and triticale varieties to Tilletia indica, the causal agent of Karnal bunt

The reactions of 47 Canadian wheat and triticale cultivars to Tilletia indica Mitra, the causal agent of Karnal Bunt (KB), were evaluated in the field at Centro de Investigaciones Agricolas del Noroeste (CIANO), Yaqui Valley, Mexico, during 1998 and 1999. The majority of lines and cultivars flowered during January and February, which coincided with the onset of cooler temperatures and high relative humidity required for optimum infection by the fungus. Canada Western Amber Durum (CWAD) and triticale were resistant, ranging from 0 to 6% infection. Canada Western Red Spring (CWRS) wheats were also generally resistant, but the cultivars Roblin, BW90 and Laura, and the experimental line Roblin*2/BW 553, were susceptible, ranging from 11 to 28% in treatments with the highest infection levels. Canada Western Extra Strong (CWES) wheats varied in reaction from moderately resistant to susceptible, ranging from 1 to 15% infection. Canada Prairie Spring (CPS) wheats were generally susceptible, exhibiting infection levels ranging from 5 to 31% infection in the most severely infected treatments. Canada Western Soft White Spring (CWSWS) wheats were uniformly susceptible; the highest recorded infection level among Canadian wheats was observed on AC Reed (38%) during 1999. The susceptibility of CPS and CWSWS cultivars may represent an increased risk to the establishment of KB if the fungus were to become introduced into western Canada. Key words: Karnal bunt, wheat, disease resistance, disease susceptibility

Out-crossing rates for 10 Canadian spring wheat cultivars

The genetic purity of pedigreed wheat seed can be compromised by inter-cultivar cross-pollination. Common wheat (Triticum aestivum L.) is assumed to be highly self-pollinated, an assumption that has not been verified for more recent western Canadian spring wheat cultivars. This field study was designed to estimate the outcrossing (OC) rate in three market classes of spring wheat in each of 2 yr and to determine whether OC rates were associated with specific spike characteristics. Highest OC rates were detected for the cultivar Oslo (6.05%) followed by Rongotea (2.30%), Roblin (1.43%), Wildcat (1.35%), Biggar (1.05%) and Glenlea (0.95%). In contrast Katepwa and CDC Makwa had OC rates of 0.38 and 0.30%, respectively. The cultivars Oslo, Columbus, Roblin and Glenlea tended to have lower iodine pollen viabilities. Of those four cultivars, three had higher-than-average OC rates. No single spike characteristic was correlated with OC rate. However, the cultivars Oslo, Wildcat and Glenlea had high OC rates, low pollen staining and spikes which tapered at the extremeties. Furthermore, cultivars with higher OC rates tended to have a greater degree of spikelet opening at anthesis. The high levels of OC observed in this study could result in obvious off-types if morphologically diverse cultivars were grown in adjacent pedigreed seed fields. The current 3 to 10 m isolation distance for pedigreed wheat seed production may not be enough to ensure that OC is minimized. Key words: Cross-pollination, spring wheat, market class

Influence of planting dates on the aggressiveness of common bunt races (Tilletia triticiandT. laevis) to Canadian spring wheat cultivars

Cultivars varying in nonspecific resistance to common bunt were evaluated for their reaction to different races of Tilletia tritici and T. laevis following four different planting dates during 1987 and 1988. Percent bunted tillers decreased with successive planting dates from early April to late May. Percent infection in the highly susceptible cultivar HY320 was negatively associated with air and soil temperatures averaged over a 35-day period following seeding in both years. Most western Canadian spring wheat cultivars were resistant when planted during May but only Columbus was consistently rated resistant for all planting dates. However, in 1987, there was an increase in bunt levels in most cultivars on the May 25 planting date, and the highly susceptible cultivars HY320, Owens, and Fielder exhibited a susceptible reaction. Variability in aggressiveness was observed among races: T-19 was the most aggressive and L-16 was the least. The aggressiveness of races interacted with planting dates, indicating t...

STATUS OF BUNT RESISTANCE IN WESTERN CANADIAN SPRING WHEAT AND TRITICALE

The reaction of western Canadian spring wheat and triticale to a composite of races of common bunt (Tilletia caries and T. foetida) was assessed in field studies conducted over 2 yr at three locations. Triticale and durum wheat were designated immune or highly resistant. Among cultivars of hard red spring wheat, Columbus was the most resistant followed by Katepwa, Leader, and Lancer. Neepawa, Park, and Marquis were intermediate in resistance. Roblin and Laura were susceptible. The Canadian Prairie Spring wheats HY320 and HY360 were highly susceptible and susceptible, respectively, whereas Oslo was intermediate in resistance. The utility wheats Wildcat and Glenlea were highly susceptible and intermediate, respectively. The soft white wheats Owens and Fielder were susceptible. The reaction of the cultivars to individual bunt races was evaluated under controlled environment conditions to identify specific Bt resistance genes. This revealed the presence of Bt1 in the cultivar Canuck and Bt10 in the line BW-553. Resistance in the other cultivars of hard red spring wheat appeared to be race nonspecific in nature. Race specificity was apparent in durum wheat but the virulence pattern could not be employed to identify specific Bt resistance genes. The potential impact of seeding large acreages to spring wheat cultivars that are highly susceptible to common bunt is discussed.Key words: Tilletia caries, Tilletia foetida, bunt (common)