J. M. Clarke

Identification of QTL and association of a phytoene synthase gene with endosperm colour in durum wheat

The yellow colour of durum wheat (Triticum turgidum L. var durum) semolina is due in part to the presence of carotenoid pigments found in the endosperm and is an important end-use quality trait. We hypothesized that variation in the genes coding for phytoene synthase (Psy), a critical enzyme in carotenoid biosynthesis, may partially explain the phenotypic variation in endosperm colour observed among durum cultivars. Using rice sequence information, primers were designed to PCR clone and sequence the Psy genes from Kofa (high colour) and W9262-260D3 (medium colour) durum cultivars. Sequencing confirmed the presence of four Psy genes in each parent, corresponding to a two member gene family designated as Psy1-1, Psy1-2 and Psy2-1 and Psy2-2. A genetic map was constructed using 155 F1-derived doubled haploid lines from the cross W9262-260D3/Kofa with 194 simple sequence repeat and DArT® markers. Using Psy1-1 and Psy2-1 allele-specific markers and chromosome mapping, the Psy1 and Psy2 genes were located to the group 7 and 5 chromosomes, respectively. Four quantitative trait loci (QTL) underlying phenotypic variation in endosperm colour were identified on chromosomes 2A, 4B, 6B, and 7B. The Psy1-1 locus co-segregated with the 7B QTL, demonstrating an association of this gene with phenotypic variation for endosperm colour. This work is the first report of mapping Psy genes and supports the role of Psy1-1 in elevated levels of endosperm colour in durum wheat. This gene is a target for the further development of a molecular marker to enhance selection for endosperm colour in durum wheat breeding programs.

Lillian hard red spring wheat

Lillian, hard red spring wheat (Triticum aestivum L.), exhibited reduced cutting by the wheat stem sawfly (Cephus cinctus Nort.) and is adapted to the Canadian prairies. Lillian produced significantly more grain yield than AC Abbey and Neepawa and its grain yield and protein concentration were similar to AC Barrie. It matured significantly earlier than Superb and Laura, and had improved resistance to leaf rust and leaf spotting diseases compared to AC Abbey. Lillian is eligible for all grades of the Canada Western Red Spring (CWRS) wheat class. Key words: Triticum aestivum L., cultivar description, grain yield and protein, resistance wheat stem sawfly, leaf and stem rust

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 o...

Identification and mapping of leaf, stem and stripe rust resistance quantitative trait loci and their interactions in durum wheat.

Leaf rust (Puccinia triticina Eriks.), stripe rust (Puccinia striiformis f. tritici Eriks.) and stem rust (Puccinia graminis f. sp. tritici) cause major production losses in durum wheat (Triticum turgidum L. var. durum). The objective of this research was to identify and map leaf, stripe and stem rust resistance loci from the French cultivar Sachem and Canadian cultivar Strongfield. A doubled haploid population from Sachem/Strongfield and parents were phenotyped for seedling reaction to leaf rust races BBG/BN and BBG/BP and adult plant response was determined in three field rust nurseries near El Batan, Obregon and Toluca, Mexico. Stripe rust response was recorded in 2009 and 2011 nurseries near Toluca and near Njoro, Kenya in 2010. Response to stem rust was recorded in field nurseries near Njoro, Kenya, in 2010 and 2011. Sachem was resistant to leaf, stripe and stem rust. A major leaf rust quantitative trait locus (QTL) was identified on chromosome 7B at Xgwm146 in Sachem. In the same region on 7B, a stripe rust QTL was identified in Strongfield. Leaf and stripe rust QTL around DArT marker wPt3451 were identified on chromosome 1B. On chromosome 2B, a significant leaf rust QTL was detected conferred by Strongfield, and at the same QTL, a Yr gene derived from Sachem conferred resistance. Significant stem rust resistance QTL were detected on chromosome 4B. Consistent interactions among loci for resistance to each rust type across nurseries were detected, especially for leaf rust QTL on 7B. Sachem and Strongfield offer useful sources of rust resistance genes for durum rust breeding.

Gluten index compared with SDS-sedimentation volume for early generation selection for gluten strength in durum wheat

Gluten strength is an important end-use quality factor in durum wheat [Triticum turgidum L. ssp. durum (Desf.) Husn.], affecting pasta manufacture and cooking quality. The objective of this research was to determine the inheritance and heritability of gluten index in comparison with the widely used SDS-sedimentation (sodium dodecyl sulphate) technique for selection for gluten strength. Seven durum populations were grown in replicated, multi-location, multi-year field trials in Saskatchewan, Canada, during the period 1995 to 2002. Gluten index and SDS-sedimentation volume were determined on all plots after harvest. Both traits were affected by genotype, and to a lesser extent by year or location. Genotype environmental interactions were generally minor. The majority of genotypes in each population had similar relative ranking for gluten index and SDS-sedimentation volume in each environment. Both traits were highly heritable, ranging from 0.80 to 0.97, and both were complexly inherited with estimates of ef...

AC Vista hard white spring wheat

AC Vista is a hard white spring wheat (Triticum aestivum L.) with resistance to preharvest sprouting. It combines high grain yield and resistance to prevalent races of leaf rust, stem rust, common bunt, and loose smut except race T9 in a semidwarf photoperiod insensitive background. AC Vista has harder kernels and stronger gluten than AC Karma. It is eligible for grades of the Canada Prairie Spring (White) wheat class. Key words: Triticum aestivum L., cultivar description, white spring wheat, preharvest sprouting resistance, common bunt resistance, high grain yield

Effect of leaf spotting diseases on grain yield and seed traits of wheat in southern Saskatchewan

Although leaf spotting diseases have been reported to have a negative effect on grain yield and seed characteristics of wheat (Triticum spp.), the magnitude of such effects on wheat grown on dryland in southern Saskatchewan is not known. A fungicide experiment was conducted at Swift Current (Brown soil) and Indian Head (Black soil) from 1997 to 1999 to determine the effect of leaf spotting diseases on yield and seed traits of wheat. Two fungicides, Folicur 3.6F and Bravo 500, were applied at different growth stages on three common wheat (Triticum aestivum L.) and three durum wheat (T. turgidum L. var durum) genotypes. Fungicide treatments generally did not affect yield, kernel weight, test weight or grain protein concentration, and these effects were relatively consistent among genotypes. Folicur applied at head emergence in 1997 and at flag leaf emergence and/or head emergence in 1998 increased yield at Indian Head (P < 0.05). Fungicides applied at and before flag leaf emergence tended to increase kernel...

AC Cadillac hard red spring wheat

AC Cadillac, a hard red spring wheat (Triticum aestivum L.), is adapted to the Canadian Prairies. It combines high grain yield with high grain protein concentration, heavy kernel and volume weights. It has improved resistance to leaf spots compared with the check cultivars, and resistance to prevalent races of leaf rust, stem rust, loose smut, and common bunt. AC Cadillac is eligible for grades of Canada Western Red Spring wheat. Key words: Triticum aestivum L., red spring wheat, yield, protein, disease resistance, volume weight

AC Abbey hard red spring wheat

AC Abbey, hard red spring wheat (Triticum aestivum L.), is adapted to the Canadian prairies. It is significantly shorter than any of the check cultivars and has solid stems. AC Abbey expressed higher grain yield, earlier maturity, and heavier kernels than AC Eatonia, the solidstem check cultivar. It is resistant to the wheat stem sawfly (Cephus cinctus Nort.) and to prevalent races of common bunt and has moderate resistance to leaf rust and stem rust. AC Abbey is eligible for grades of Canada Western Red Spring wheat. Key words: Triticum aestivum L., red spring wheat, yield, wheat stem sawfly, plant height, maturity

Inheritance of stem solidness in eight durum wheat crosses

Yield loss from sawfly (Cephus cinctus Norton) can be prevented by growing solid-stemmed wheat. No solid-stemmed durum cultivars (Triticum turgidumL. var. durum) are registered in Canada, even though solid-stemmed lines are available. Understanding the inheritance of stem solidness in such lines would be useful to breeders. Eight crosses were made between solid-stemmed and hollow-stemmed durums: Trinakria/DT369, Trinakria/DT367, Hugenot G/DT369, Hugenot W/DT369, 8678-1048A/Hugenot W, 8678-1048A/Hugen ot G, Kamilaroi/Hugenot G, and W9262-260D3/Kofa. Trinakria, Hugenot G, Hugenot W and W9262-260D3 are solid-stemmed and the other parents are hollow stemmed. Stem solidness was measured in field trials. The F1 were solid-stemmed, and the F2 of five of the seven crosses were not significantly different (P > 0.05) from a three solid-stemmed to one hollow-stemmed segregation ratio. The backcross of the solid-stemmed parents with the F1 was 100% solid-stemmed, and the backcross of the hollow-stemmed parents with t...