Western Red Spring Wheat Cultivars Research Articles

Leaf water relations and osmotic adjustment of Canada Western Red Spring wheat cultivars subjected to drought.

For wheat (Triticum aestivum ), sustained crop yield at limited soil water availability has been linked to osmotic adjustment (OA) - a physiological mechanism that aids maintenance of leaf hydration status, turgor (P ) and growth. 'Canada Western Red Spring' (CWRS) wheat cultivars are typically grown in rainfed areas with milder climates, but ongoing climate change is increasesing the frequency and intensity of drought events. The overarching goal of this study was to elucidate if commercially used CWRS cultivars ('Superb', 'Stettler', 'AAC Viewfield') have the ability for leaf OA. Measurements of leaf water relation parameters (water potential, Ψ ; solute potential, Ψ s ; stomatal conductance, g s ; relative water content, RWC) showed that all three cultivars reached zero P (= Ψ - Ψ s ) at a leaf Ψ of -1.1MPa. Prior to that, P maintenance in 'Superb' and 'AAC Viewfield' was associated with a significant reduction in leaf Ψ s and OA contributed 0.53MPa ('Superb') and 0.73MPa ('AAC Viewfield'). Our data analyses provided no support for the existence of OA in 'Stettler'. Under water deficit, leaf g s was significantly higher in 'AAC Viewfield' compared to 'Stettler'; it was intermediate in 'Superb'. Together, drought tolerance in CWRS wheat cultivars is most likely linked to the degree of OA.

The performance of spring wheat cultivar mixtures under conventional and organic management in Western Canada

AbstractWheat (Triticum aestivum L.) cultivar mixtures may stabilize yield across environments, control air‐borne diseases, and manage pest populations in both conventional and organically managed systems. The objective of this study was to evaluate agronomic and end‐use quality characteristics of wheat cultivar mixtures. Five Canada Western Red Spring wheat cultivars (‘Go Early’, ‘Carberry’, ‘Glenn’, ‘CDC Titanium’, and ‘Lillian’) differing in agronomic and quality traits were selected to compose 20 possible two‐way and three‐way combinations. Field experiments were conducted in four conventional and two organic environments in Alberta and Saskatchewan, Canada in 2016 and 2017. Wheat cultivar mixtures out‐yielded their mid‐component averages in both conventional and organic environments. Averaged across locations, two mixtures, Glenn–Lillian and Go Early–Glenn–Lillian, significantly out‐yielded their mid‐components. The overall yield increase ranged from 3.3 to 14.1%, with a mean of 0.18 Mg ha–1 over different environments. Grain yield was negatively correlated with protein content (r = –.53) and falling number was negatively correlated with sedimentation volume (r = –.66) in conventional systems. Protein content was positively correlated with falling number in both conventional (r = .60) and organic (r = .40) systems. Days to maturity was positively correlated with yield (r = .40) and sedimentation volume (r = .40), but negatively correlated with falling number (r = –.80) in organic system. Sole cultivars were more stable under conventional, and mixtures were more stable under organic management. Our results suggest that wheat cultivar mixtures may provide yield advantage under abiotic stresses in conventional, whereas superior yield and grain quality in organic management.

Investigating Genetic Progress and Variation for Nitrogen Use Efficiency in Spring Wheat

Improved N use efficiency (NUE) increases wheat (Triticum aestivum L.) yields and reduces N losses in the environment. We investigated genetic variation and correlations among agronomic and NUE traits in Canada Western Red Spring wheat cultivars to further improve NUE. Trials were conducted for 3 yr at two locations in Alberta, Canada, under two levels of N (200 and ~50 kg ha−1). Genotype × environment interaction was significant for traits associated with vegetative growth, and genotype × N fertilizer treatment interaction was significant for important yield and NUE traits. There were significant positive correlations between total dry matter and N uptake efficiency (NUpE) in the high (r = 0.74, P < 0.05) and low (r = 0.83, P < 0.05) N treatments. The effect of dwarfing Rht‐1b allele was more prominent under high N treatment in increasing NUE. However, cultivars with Rht‐1b allele showed inconsistent results for NUpE, indicating that Rht alleles might have pleiotropic effects on N uptake. Grain yield, NUE, and N utilization efficiency (NUtE) exhibited genetic improvement over time only under high N treatment. Our results indicated that grain yield increased mainly due to improved harvest index (HI), suggesting improvement in C assimilation rather than N partitioning efficiency. Nitrogen use efficiency may further be improved by intercrossing cultivars with high HI, N harvest index, and NUtE and those with good NUpE, while using total dry matter production as a selection criterion.

Environmental Effects on the Relative Competitive Ability of Canola and Small-Grain Cereals in a Direct-Seeded System

Growing crops that exhibit a high level of competition with weeds increases opportunities to practice integrated weed management and reduce herbicide inputs. The recent development and market dominance of hybrid canola cultivars provides an opportunity to reassess the relative competitive ability of canola cultivars with small-grain cereals. Direct-seeded (no-till) experiments were conducted at five western Canada locations from 2006 to 2008 to compare the competitive ability of canola cultivars vs. small-grain cereals. The relative competitive ability of the species and cultivars was determined by assessing monocot and dicot weed biomass at different times throughout the growing season as well as oat (simulated weed) seed production. Under most conditions, but especially under warm and relatively dry environments, barley cultivars had the greatest relative competitive ability. Rye and triticale were also highly competitive species under most environmental conditions. Canada Prairie Spring Red wheat and Canada Western Red Spring wheat cultivars usually were the least competitive cereal crops, but there were exceptions in some environments. Canola hybrids were more competitive than open-pollinated canola cultivars. More importantly, under cool, low growing degree day conditions, canola hybrids were as competitive as barley, especially with dicot weeds. Under most conditions, hybrid canola growers on the Canadian Prairies are well advised to avoid the additional selection pressure inherent with a second in-crop herbicide application. Combining competitive cultivars of any species with optimal agronomic practices that facilitate crop health will enhance cropping system sustainability and allow growers to extend the life of their valuable herbicide tools.

Modeling leaf appearance rate for Canada Western Red Spring wheat cultivars

The rate of leaf appearance [LAR (d-1)] was observed for two older (Marquis and Neepawa) and two newer (AC Barrie and AC Elsa) Canada Western Red Spring (CWRS) wheat (Triticum aestivum L.) cultivars grown in a semiarid environment on the Canadian prairies for four years. Although the newer cultivars significantly increased yield LAR did not change when compared with the older cultivars. A simulation model developed by Jame et al. (1998a), and using coefficients for Neepawa determined from a previous study adequately predicted LAR for all four cultivars.Key words: Wheat, leaf appearance rate, temperature, daylength, model

Flag leaf physiological traits in two high-yielding Canada Western Red Spring wheat cultivars

Because of the common negative correlation between grain yield and grain protein (nitrogen) concentration, it is difficult to improve yield in the Canada Western Red Spring (CWRS) wheat (Triticum aestivum L.) class, which characteristically possesses high quantity and quality of protein. Previous studies found that the increased yield of some new CWRS cultivars relative to old cultivars was mainly attributed to higher yield per spike and spike filling rate and more efficient carbohydrate and N partitioning to the grain. The objective of this study was to investigate if the yield increase of two new CWRS cultivars, AC Barrie (registered in 1996) and AC Elsa (registered in 1997), is associated with a change in photosynthetic rate or other physiological traits of flag leaves compared with two old cultivars, Neepawa (registered in 1969) and Marquis (introduced in 1909). No difference was found between new and old cultivars in flag leaf photosynthesis rate or nitrogen concentration. Both new cultivars tended to have lower specific leaf area (SLA) and higher N accumulation per leaf when flag leaves were young and more N remobilization during grain filling compared with old cultivars. Over the 2 yr, flag leaf N remobilizations of AC Elsa and AC Barrie averaged 69 and 32% higher than Marquis and 50 and 17% higher than Neepawa, respectively. The enhanced flag leaf N remobilization along with increased N remobilization from other organs of new cultivars shifted the undesirable negative relationship between grain yield and grain protein concentration. AC Elsa had greater total photosynthesis per flag leaf than other three cultivars due to its larger leaf area and longer green leaf duration. Further research is required to determine if low SLA, large flag leaf and long green leaf duration are effective selection criteria for high yielding CWRS cultivars. Key words: Flag leaf, photosynthesis, specific leaf area, nitrogen remobilization

The Weed-Competitive Ability of Canada Western Red Spring Wheat Cultivars Grown under Organic Management

Competition from weeds can reduce grain yields in both conventional and organic systems. Plant height, tillering, and elevated photosynthetically active radiation interception are some of the traits thought to help confer competitive ability in cereal grains. Crop cultivars developed before the advent of modem, high-input agriculture may be better suited to lower soil nutrient levels and elevated weed competition. Twenty-seven spring bread wheat (Triticum aestivum L.) cultivars, representing 114 yr of Canadian wheat breeding, were grown at conventionally and organically managed sites in north central Alberta over a 3-yr period. Average conventional yields were 63% greater than organic yields, and average overall weed biomass was significantly greater under organic management. Earlier flowering and maturity were more important for achieving high grain yield in organic fields than in conventional fields. Greater numbers of spikes m-2 were associated with increased grain yield in organic fields but were not in conventional fields. In organic fields, increased plant height and early maturity were associated with reduced weed biomass, while strong early season vigor was related to increased yield, increased spikes m -2 , and reduced weed biomass. A competitive crop ideotype for organically grown spring wheat in northern growing regions of the Canadian Prairies should include taller plants, with fast early season growth, early maturity, and elevated fertile tiller number.

Physiological characteristics of recent Canada Western Red Spring wheat cultivars: Components of grain nitrogen yield

Genetic yield gains have been difficult to achieve within the Canada Western Red Spring (CWRS) wheat (Triticum aestivum L.) class, partially because of the requirement for high protein concentration. A previous study indicated that four newer, high-yield CWRS cultivars (registered 1994–1997) also had higher protein yields. The objective of the present study was to determine if the increase in grain nitrogen (protein) yield of the four newer wheat cultivars, relative to two older cultivars, Neepawa (registered in 1969) and Marquis (introduced in 1909), resulted from increased plant nitrogen uptake, more efficient utilization of nitrogen, or a combination of these factors. The higher nitrogen yields were primarily attributed to more efficient utilization and redistribution of the nitrogen rather than increased uptake of soil nitrogen. The nitrogen harvest index (NHI) of the new cultivars, considered as a group, was higher than the NHI of Neepawa, which in turn was higher than that of the much older cultivar Marquis. The NHI of each of the new cultivars was higher than that of Marquis. The nitrogen concentration in the non-grain tissue at maturity (NGNCM) of the new cultivars, considered as a group, was lower than that of Neepawa, which in turn was lower than the NGNCM of Marquis. At maturity, all five tissues (leaf blade, stem plus sheath, peduncle, glume, and rachis) for the new cultivars and Neepawa had lower nitrogen concentrations than for the corresponding tissues of Marquis. The nitrogen concentration of the peduncle and leaf-blade tissues of the new cultivars, as a group, were also lower at maturity than the corresponding nitrogen concentrations for Neepawa. The results suggest that low non-grain nitrogen concentration at harvest is associated with improved NHI and grain nitrogen yield in CWRS wheat. This information may improve our understanding of the higher protein yields that have been achieved within this class, and assist in the selection of future parents. Key words: Nitrogen harvest index, nitrogen uptake, nitrogen yield, protein, remobilization, Triticum aestivum

Physiological characteristics of recent Canada Western Red Spring wheat cultivars: Yield components and dry matter production

Genetic yield gains have been difficult to achieve within the Canada Western Red Spring (CWRS) wheat (Triticum aestivum L.) class because of stringent quality requirements and a short growing-season environment with low precipitation and high temperatures. Understanding the physiological basis of yield gains may provide breeders with better insight in selecting parents and screening tools to identify desirable genotypes. The objective of the present study was to compare four new CWRS wheat cultivars with two older cultivars, Neepawa and Marquis, for yield components and dry matter production. When grown at Swift Current, SK, for 3 yr, the average yield for the group of new cultivars was 34.3% higher than that of Marquis (P < 0.01), and 5.9% higher than that of Neepawa (P = 0.10). The new cultivars, as a group, had significantly increased kernel weight, kernels per spike, yield per spike, and spike-filling rate relative to either of the older cultivars. When cultivars were compared individually, all four of the new cultivars had significantly higher yield per spike and spike-filling rate than Neepawa or Marquis, suggesting that these factors may be closely related to the increased yields of the newer cultivars. The trend toward higher kernel weight and kernels per spike suggests that the new cultivars have increased the sink size of each tiller. The number of spikes per plant and the length of the grain-filling period do not appear to be associated with the increased yield. Harvest index of the group of new cultivars, while significantly higher than that of Marquis, has not increased significantly compared to Neepawa, probably because this group is similar in height to Neepawa. Key words: Triticum aestivum, wheat, Canada Western Red Spring, yield, quality

Erratum: Gliadin alleles in Canadian western red spring wheat cultivars: use of two different procedures of acid polyacrylamide gel electrophoresis for gliadin separation

Erratum: Gliadin alleles in Canadian western red spring wheat cultivars: use of two different procedures of acid polyacrylamide gel electrophoresis for gliadin separation

Gliadin alleles in Canadian western red spring wheat cultivars: use of two different procedures of acid polyacrylamide gel electrophoresis for gliadin separation

Gliadin allele compositions of 21 Canadian spring common wheat cultivars, most of which belong to the Canada western red spring (CWRS) class, were studied and great similarity in their genotypes was confirmed. It was found that alleles frequent in the set of Canadian wheats (such as Gli-B1d, Gli-D1j, Gli-A2m, and Gli-D2h) are very rare or absent in common wheat cultivars from other regions and countries studied earlier, indicating that germplasm of CWRS cultivars is rather unique. It may be suggested that alleles frequent in Canadian cultivars relate to important technological characteristics of these wheats and may possibly serve as marker genes during selection for quality traits. Similarity of gliadin electrophoregrams obtained by two different acid polyacryl-amide gel electrophoretic procedures for the same genotype was established, and the component composition of allelic variants of blocks of gliadin components found in the set of Canadian cultivars and in standard cultivars Chinese Spring and Bezostaya 1 are described.