Canadian Spring Wheat Research Articles

Response of eight Canadian spring wheat (Triticum aestivum L.) cultivars to copper: Pollen viability, grain yield plant−1 and yield components

Eight Canadian spring wheat (Triticum aestivum L.) cultivars, Katepwa, Roblin, Park, Laura, Conway, Oslo, Columbus and Biggar, were tested in the field for copper (Cu) use efficiency. The experiment was conducted at Stony Plain, Alberta on an Orthic, Dark Grey, Chernozemic, Cu deficient (0.48 μg g−1) soil. A split-plot experimental design was used with (+Cu) and without (−Cu) copper treatment of 12.2 kg copper sulphate ha−1. Significant (P ≤ 0.05) effects due to cultivar, Cu, season, and cultivar × Cu interaction were observed, indicating differential response of the test cultivars to Cu for yield and yield components. Cu application significantly (P ≤ 0.05) improved the number of grains spike−1, and floret fertility of Roblin, Laura, Park and Oslo, and increased the grain yield of Conway by 10%. Significant (P ≤ 0.05) effects due to cultivar, year and year × cultivar interaction for Cu efficiency indicated that Cu use efficiency varied with both year and cultivar. Biggar showed the highest Cu use efficiency (108%) while Oslo showed the lowest (57%). Key words:Triticum aestivum L., cultivars, copper, pollen viability, copper use efficiency

Pedigree analysis of the origin of manganese tolerance in Canadian spring wheat (Triticum aestivum L.) cultivars

Breeding wheat (Triticum aestivum L.) for tolerance to manganese (Mn) might be in some cases more feasible and economical than use of soil amendments. As part of research on the heritability of Mn tolerance, a study on the level of Mn tolerance in Canadian wheat cultivars and its probable origin was accomplished by analysis of cultivar pedigrees and drawing phylogenetic maps to discern filial relationships. Cultivar tolerance to Mn was determined by relative root weight (RRW) in solution culture in the presence of 500 μM Mn. A total of 91 cultivars were screened, 76 of which were Canadian. These data, together with data from another 28 cultivars reported in the literature, were used to draw two pedigree maps, a map for Canadian cultivars only, and a map for the Mn-tolerant Canadian cultivars Norquay and Laura. Results indicated a range of tolerance to Mn among Canadian cultivars. Manganese tolerance, found in either Canadian or foreign germplasm, and of either recent or older selection or origin, seems to have originated from land races from Rio Grande do Sul, the southernmost state of Brazil. Tolerance may have been introduced into Canadian germplasm directly by the use of Brazilian cultivars as parents, or indirectly by the introduction of Mexican germplasm with Brazilian parentages. This information will help the plant breeder to develop plant breeding systems, and may also help in the study of the mechanisms for Mn tolerance in wheat.

Spatial variation in seed size and seed set on spikes of some Canadian spring wheat cultivars

The seed size (mass) distribution of grain on individual spikes of four Canadian wheat cultivars (Glenlea, HY320, Pitic 62 and Neepawa, Triticum aestivum L.) was determined on plant samples from two replicates of the 1984 High Yielding Wheat Cooperative trial grown at Ellerslie, Alberta. Specific grain mass was determined for individual floret locations on all spikes of each plant, and sterile floret locations were also determined. For all four cultivars the maximum amount of seed size variation from the samples was attributable to variation at the floret level, accounting for 92% of the seed size variance of Pitic 62, down to 74% for Neepawa. Neepawa differed from the other three cultivars in demonstrating a high (20%) and significant variance in seed size attributable to spikelet position. Pitic 62 was the only cultivar of the four that demonstrated significant variance (12%) due to plant differences within replicates. Consistent with previous literature, approximately 50% of total plant yield was accounted for by the mainstem spike, decreasing to 8 to 15% on the third spike. The mean number of seeds spike−1 on the mainstem was 26.8 (Neepawa), 35.9 (Glenlea), 46.8 (HY320) and 48.6 (Pitic 62), but this number decreased in response to tiller order, as did seed mass and floret fertility. Quadratic functions were calculated fitting seed mass to floret position (1 proximal to 4 distal), and were significant in all cases, with R2 values of 63% for Neepawa, 56% for Glenlea, 82% for Pitic 62 and 89% for HY320. The fitted quadratics suggest an optimization of seed size at floret site 2 for some cultivars, with a rapid decrease in seed size at floret sites 3 and 4, especially for the high-yielding cultivars Glenlea and Pitic 62. Fourth florets of the latter cultivars were shown in frequency distributions to produce seeds smaller than the mean seed size of the Neepawa seed size expected at Florets 1, 2 and 3. Large negative skewnesses for seed size for Glenlea, HY320 and Pitic 62 also underscored the tendency for the high-yielding cultivars to produce relatively large numbers of small seeds. Although determined in only one site-year, these differences in seed size distribution pattern amongst cultivars are of major significance to visual identification systems. Large-seeded, high-yielding wheats in pure stand can be expected to produce a significant number of small-seeded kernels that might be confused by visual inspection with CWRS seed type. Key words: Grain, grading, cultivar registration, seed identification, high-yielding wheats

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)

An evaluation of a new rhombic grid selection, gridded mass selection and simple mass selection methods for yield improvement in wheat

An experiment was conducted in Winnipeg, Manitoba, Canada to: (1) ascertain the efficiency of gridded mass selection; (2) to determine if additional selection efficiency can be achieved through refinement of the gridded mass selection procedure; and (3) to determine if the degree of homozygosity has an effect on response to single-plant selection. Three selection methods [simple mass selection (SMS); gridded mass selection (GMS); and a new rhombic grid selection (RGS)] were applied to four populations [a conventional F2 (CON-F2); an intermated F2 (INT-F2); and 2 partial backcrossed populations] developed from a biparental cross involving the Canadian spring wheat cultivars, ‘Glenlea’ and ‘Sinton’. Averaged over the 4 populations, a single cycle of RGS (10% selection intensity) increased yield by about 9.5%, whereas GMS and SMS increased yield by approximately 4.5% and 3.1%, respectively. The degree of homozygosity of individual plants that make up the population appeared to have an effect on the efficiency of selection. In general, selection was more efficient in the two partial backcrossed populations, and least efficient in the CON-F2 and INT-F2 populations. The largest response to selection (15.9%) was attained when RGS was applied in the backcross to Glenlea population, and the lowest response (1.2%) when SMS was enforced in the CON-F2 population. This paper represents the first report on the efficiency of rhombic grid selection for yield improvement in cereal crops.

Aluminum tolerance in Canadian spring wheats

Abstract Canadian spring wheat cultivars (Triticum aestivum L.) and imported reference cultivars were grown in nutrient solution at varying aluminum concentrations and treatment durations. Relative root lengths, with and without aluminum, and hematoxylin ratings were the criteria used in evaluating aluminum tolerance. Relative root length results indicated a wide range in aluminum tolerance, but three tolerance classes (tolerant, intermediate and sensitive) were constructed based on reference cultivar performance. Most of the tolerant cultivars (HY 320, Romany, Kenya Kongoni, Maringa, PF 7748, and Cinquentenario) were all derived from Brazilian or Mexican cultivars. Vernon ranked as tolerant in contrast to its recurrent parent, Opal, which was intermediate in reaction to aluminum. Some of the older Canadian cultivars (Kitchener, Chinook, Renown, Marquis and Prelude) exhibited tolerance but the lineage of aluminum tolerance could not be determined. It appears that plant selection for characters other than ...

The influence of different temperature treatments on anther culture response of spring wheat ( Triticum aestivum L.)

Six Canadian spring wheat genotypes ( Triticum aestivum L.) were used to study the influence of cold and heat treatments on the efficiency of anther culture. Anther callus yield was increased when the anthers were incubated at 32°C for 6 days prior to incubation at 26°C. Cold treatment of whole spikes or separated anthers adversely affected the callusing efficiency of anthers. While adverse effects of short-term cold treatment were reversible by heat treatment, long-term exposure to cold caused irreversible damage. Initial heat treatment allowed the anthers to remain unaffected by subsequent cold treatment. Plant regeneration was obtained from up to 38% of the induced calli and only very few cali produced albinos.

IDENTIFICATION OF CANADIAN AND AMERICAN WHEAT CULTIVARS BY SDS GRADIENT PAGE ANALYSIS OF GLIADIN AND GLUTENIN SUBUNITS

Sodium dodecyl sulphate gradient polyacrylamide gel electrophoresis (SDSGPAGE) was used to resolve gliadin and high- and low-molecular-weight glutenin subunits from 19 registered Canadian spring wheat cultivars eligible for Canada Western Red Spring (CWRS) and Canada Prairie Spring (CPS) wheat grades and eight nonregistered spring wheat cultivars from the U.S.A. Reproducible molecular weight estimates were obtained for wheat proteins of apparent molecular weights ranging from 34 238 to 136 174 (avg. CV = 0.72%). Eight different patterns of HMW glutenin subunits consisting of 7–11 protein bands were observed for the 27 cultivars and their biotypes. SDSGPAGE was able to discriminate among the majority of cultivars with all non-registered cultivars and their biotypes distinguishable from registered cultivars. Separation of glutenin subunits along with gliadins provided additional protein bands which assisted in the discrimination of cultivars.Key words: SDS gradient PAGE, wheat cultivar identification, gliadin, glutenin subunits

WHEAT QUALITY EVALUATION. 3. INFLUENCE OF GENOTYPE AND ENVIRONMENT

Agronomic and quality data from eastern Canadian spring and winter wheat trials, for an equivalent of 15 trial yr, were analyzed to determine the relative effects of genotype and environment on quality. Considerable genetic variability was detected for many of the 19 measurements studied, indicating that positive results from selection could still be expected in these populations. A large environmental effect was observed for yield, protein and protein related parameters. The consequence of this environmental modification was considered with regard to breeding programs. Except for a few instances, genotype × year and genotype × location interactions were found to be relatively insignificant. However, indirect evidence suggested that the genotype x year × location interaction could be of greater concern.

RUST REACTIONS OF CHINESE WHEAT VARIETIES AND CERTAIN CANADIAN HYBRID STRAINS

About 160 Chinese spring wheats and a number of Chinese winter wheats were tested in the seedling stage in the greenhouse to determine their reaction to eight physiologic races of stem rust (Puccinia graminis Tritici) and to four physiologic races of leaf rust (Puccinia triticina). The spring wheats were also subjected, in the field, to epidemics of stem rust and leaf rust in which a large number of physiologic races of each rust were employed. The wheats were classified as one or another of the following species: Triticum vulgare, T. compactum, T. durum, and T. turgidum.By means of these tests, it has been demonstrated that the Chinese wheats are rather highly susceptible to the physiologic races of stem rust prevalent in North America. Many of the wheats showed, however, considerable resistance to leaf rust in both the greenhouse and the field tests. Varieties resistant to leaf rust were present in all of the four above-mentioned species.Seventy-five lines of Canadian spring wheat derived from a cross between Renown Selection, which is resistant to stem rust and moderately resistant to leaf rust, and Garnet, which in North America is resistant to stripe rust (Puccinia glumarum), were tested in the seedling stage in the greenhouse for their reaction to stripe rust. Two physiologic races (race 6 and race 13) were used in these tests. The same lines were subjected to rust epidemics in the field to determine their resistance to stem rust and leaf rust. Several of these lines were found to possess resistance to all three rusts. These lines may prove valuable breeding material in case it is desired to develop by breeding methods Chinese varieties resistant to all three of these rusts.