Nine winter wheat cultivars (Triticum aestivum Linnaeus) (Poaceae) were the source of the Sm1 gene for resistance to wheat midge, Sitodiplosis mosellana (Gehin) (Diptera: Cecidomyiidae), in spring wheat. All nine showed antibiosis characteristic of Sm1, as expected. They also showed oviposition deterrence and reduced hatch, which contributed to overall resistance. The overall level of resistance of the nine winter wheat cultivars was usually lower than that of resistant spring wheat lines in laboratory trials, but equally high in a field trial. Five of seven other North American winter wheat cultivars also showed resistance. Three of these were grown in the 1920s and earlier, before wheat varieties were officially registered. One of these, "Mediterranean", came from Europe in the 1880s and may be the origin of Sm1 in North America. Two of 11 Chinese winter wheat lines showed resistance to wheat midge but at a lower level than that characteristic of Sm1. Widespread resistance in North American winter wheat cultivars was unexpected because wheat midge has not been a pest of winter wheat for many decades. North American winter wheat cultivars can provide sources of resistance to wheat midge, particularly high levels of oviposition deterrence as exhibited by "Goens" and "Rawhide".

‘Fieldstar’ (Reg. No. CV‐1067, PI 663950) (Registration. No. 6328 by the Plant Variety Registration Office, Plant Production Division, Seed Section, Canadian Food Inspection Agency, Agriculture and Agri‐Food Canada [AAFC]) hard red spring wheat (Triticum aestivum L.) was developed and released by the Cereal Research Centre of AAFC and meets the end‐use quality specifications of the Canada western red spring wheat market class. Fieldstar is a partial backcross derivative of ‘McKenzie’, with ‘Clark’ as the donor of the Sm1 gene for midge resistance, which produces a product that reduces the palatability of developing seeds to wheat midge larvae (Sitodiplosis mosellana Géhin). Fieldstar is adapted to the eastern wheat growing regions of the Canadian prairies as determined by the Central Bread Wheat Cooperative Registration Test in 2004, 2005, and 2006. For registration testing, the performance of Fieldstar was estimated using the varietal blend Fieldstar VB, which consisted of 90% Fieldstar and 10% ‘Waskada’. The grain yield of Fieldstar was similar to that of the highest‐yielding checks, McKenzie and ‘Superb’, and expressed resistance to leaf rust (caused by Puccinia triticina Eriks.) and stem rust (caused by P. graminis Pers.:Pers. f. sp. tritici Eriks. E. Henn.) and intermediate resistance to common bunt [caused by Tilletia tritici (Bjerk.) R. Wolff and T. laevis Kuhn in Rabenh.], loose smut [caused by Ustilago tritici (Pers.) Rostr.], and Fusarium head blight [FHB; caused by Fusarium graminearum Schwabe; teleomorph Gibberella zeae (Schwein.) Petch]. Fieldstar was released because of its combination of high yield, resistance to wheat midge, and intermediate resistance to FHB.

Unity is a hard red spring wheat that meets the end-use quality specifications of the Canada Western Red Spring class. Unity is the first spring wheat cultivar registered in Canada that contains the antibiosis resistance gene Sm1, which produces a product that reduces the palatability of developing seeds to wheat midge larvae (Sitodiplosis mosellana Géhin). Unity is a partial backcross derivative of McKenzie, using Clark as the donor of the Sm1 gene for midge resistance. Unity was found to be adapted to the eastern wheat growing regions of the Canadian prairies as represented in the Central Bread Wheat Cooperative Registration Test in 2004, 2005 and 2006. For registration testing, the performance of Unity was estimated using the varietal blend Unity VB, which consisted of 90% Unity and 10% Waskada. In comparison to the check cultivars (Katepwa, McKenzie, CDC Teal, AC Barrie, and Superb), Unity was the highest yielding cultivar overall; although not significant, Unity was 5% higher yielding than McKenzie. Unity matured significantly later than Katepwa and significantly earlier than Superb. Unity had significantly shorter plant stature than Katepwa and significantly taller stature than Superb. Unity had significantly greater lodging scores than AC Barrie and Superb. The test weight of Unity was significantly higher than the best check: 0.9 kg hL-1 higher than McKenzie. Unity expressed resistance to leaf rust, stem rust and common bunt, intermediate resistance to loose smut, and susceptibility to fusarium head blight. Unity had preharvest sprouting resistance with an overall sprouting score similar to the best checks McKenzie and Superb. Unity also maintained its falling numbers following natural or artificial weathering of spikes. The end-use suitability attributes of Unity were similar to the recurrent parent McKenzie for all traits except amylograph viscosity which was significantly higher than all checks except Superb. Key words: Triticum aestivum L., cultivar description, red spring wheat, test weight, preharvest sprouting, wheat midge antibiosis

AC Cora, hard red spring wheat (Triticum aestivumL.), exhibited high levels of leaf rust resistance and was adapted to the southern Canadian prairies. AC Cora produced significantly more grain yield than Neepawa (6.8%), Columbus (6.5%) and Roblin (7.4%), and slightly more (3.0%) than Katepwa. It matured significantly earlier than Columbus, slightly earlier than Neepawa and Katepwa and slightly later than Roblin. AC Cora was similar in plant height and lodging resistance to Katepwa. AC Cora was eligible for all grades of the Canada Western Red Spring (CWRS) wheat class. Key words: Triticum aestivum L., cultivar description, grain yield, leaf and stem rust

The Canadian spring wheat (Triticum aestivum L.; Poaceae) cultivar 'Superb' was less susceptible to damage by Hessian fly, Mayetiola destructor (Say), than the spring wheat cultivars 'AC Barrie', 'AC Foremost', 'McKenzie', 'AC Domain', and 'Glenlea' in Manitoba. The partial resistance of 'Superb' was similar, at the seedling stage, to that of 'Guard', which possesses the resistance gene H18. Females laid eggs readily on all cultivars, providing no evidence for antixenosis, but few larvae developed on seedlings of 'Superb' and 'Guard', showing that antibiosis against larvae is the mechanism of resistance in these seedlings. In the field, where infestation of spring wheat takes place about 4 weeks after the seedling stage, 'Guard' continued to show high levels of resistance, but 'Superb' was less resistant, although still more resistant than highly susceptible cultivars. Infested stems of 'Superb' and 'Nordic' were less likely to break than infested steins of other cultivars, showing that these two cultivars are partially tolerant to infestation. Infested stems of 'Guard' and other cultivars showed high levels of stem breakage and are intolerant. Yield losses due to infestation by Hessian fly were mostly caused by the breakage and falling over of infested stems, which prevented the seeds on these stems from being harvested. Infested stems of all susceptible cultivars that remained standing at harvest had lower seed masses and fewer seeds per spike than uninfested stems, which contributed to yield loss. 'Grandin', a parent of 'Superb', is the probable source of resistance in 'Superb', but the pedigree of 'Grandin' provides no clue as to the gene(s) involved. The partial antibiosis and tolerance expressed by 'Superb' is sufficient to reduce losses to Hessian fly by 65% in comparison with a susceptible cultivar such as 'AC Barrie'. 'Superb' is the first Canadian spring wheat cultivar identified to have an agronomically useful level of resistance to Hessian fly.

Inheritance of resistance to a wheat midge, Sitodiplosis mosellana (Gehin), was investigated in spring wheats derived from nine resistant winter wheat cultivars. F-1 hybrids were obtained from crosses between resistant winter wheats and susceptible spring wheats, and used to generate doubled haploid populations. These populations segregated in a ratio of 1 : 1 resistant to susceptible, indicating that a single gene confers the resistance. The F-2 progeny from an intercross among spring wheats derived from the nine resistance sources did not segregate for resistance. Therefore, the same gene confers resistance in all nine sources of resistance, although other genes probably affect expression because the level of resistance varied among lines. Heterozygous plants from five crosses between diverse susceptible and resistant spring wheat parents all showed intermediate levels of response, indicating that resistance is partly dominant. Susceptible plants were reliably discriminated from heterozygous or homozygous resistant ones in laboratory tests, based on the survival and development of wheat midge larvae on one or two spikes. This powerful resistance gene, designated Sm1, is simply inherited and can be incorporated readily into breeding programme for spring or winter wheat. However, the use of this gene by itself may lead to the evolution of a virulent population, once a resistant cultivar is widely grown.

ABSTRACTThe effect of genetic substitution of two to four glutenin and gliadin subunits from a Canada Prairie Spring (CPS) cv. Biggar BSR into Alpha 16, another CPS wheat line, was studied for rheological and baking quality. Results from double substitution showed that the presence of a gliadin component from Biggar BSR (BGGL) and low molecular weight glutenin subunit 45 (LMW 45) contributed to improved dough strength characteristics. Presence of BGGL in combination with high molecular weight glutenin subunit 1 (HMW 1) or 17+18 (HMW 17+18) also showed improved dough strength over control Alpha lines. When three or four protein subunits were substituted, even though improved quality performance was observed, it was associated with the negative effect of lowered flour water absorptions in spite of similar protein contents. The study confirms that LMW glutenins, as well as gliadins, play an important role along with HMW glutenins in wheat flour quality. CPS wheat lines with improved dough strength properties can be selected from the double substitution lines with the combination of BGGL/LMW 45 and BGGL/HMW 1.

AC Assiniboia is a high-yielding, tan hulled oat cultivar possessing the crown rust resistance gene combination Pc38, Pc39, and Pc68, which is highly effective against the crown rust population on the Canadian prairies at the time of registration. It has very good resistance to loose and covered smut, good resistance to stem rust, and excellent tolerance to Barley Yellow Dwarf Virus (BYDV). AC Assiniboia has good kernel characteristics, including good protein and oil content. AC Assiniboia is well suited for the oat-growing areas of western Canada and in particular the Black soil zone of Manitoba and Saskatchewan. Key words: Oat, Avena sativa L., cultivar description

Abstract Cultivars of winter wheat, Triticum aestivum L., previously identified as possible sources of resistance to wheat midge, Sitodiplosis mosellana (Géhin), were crossed with spring wheat to produce lines with a spring growth habit and assure synchrony between insect and plant. Many of the lines showed low levels of infestation by wheat midge in the field, and 21 of these were tested for resistance in the laboratory. All test lines exhibited resistance, ranging from 58 to 100% suppression of larvae and 70 to 100% suppression of seed damage, compared with a susceptible line. Larval development was delayed and survival was reduced on all lines. This antibiosis was associated with a hypersensitive reaction in the seed surface. The hypersensitive reaction, or feeding damage by young larvae before they died, reduced the biomass of some infested resistant seeds by 28% compared with over 60% for infested susceptible seeds. Some lines also reduced the level of infestation either through oviposition deterrence or a resistance which prevented newly hatched larvae from establishing on the seed surface. A few lines also reduced the hatching rate of wheat midge eggs. The resistance was equally effective in field trials during two consecutive summers in Manitoba and Saskatchewan, with at least a 20-times difference in the level of infestation between susceptible and resistant wheats. No larvae could develop to maturity on some resistant lines. Large plots of one resistant line produced less than 1% as many larvae as a typical susceptible wheat, and the larvae that did survive produced few, small adults. This resistance is the first documented case of a high level of true resistance to wheat midge in spring wheat, distinct from asynchrony between the insect and susceptible stage of the plant. The antibiosis component of the resistance is currently being incorporated in cultivars suitable for production in western Canada. Résumé Des cultivars du blé d’hiver, Triticum aestivum L., reconnu précédemment comme une source possible de résistance à la Cécidomyie du blé, Sitodiplosis mosellana (Géhin), ont été croisés avec du blé de printemps pour produire des lignées à croissance printanière et assurer le synchronisme de l’insecte et de la plante. Plusieurs des lignées avaient des taux d’infestation de la cécidomyie plutôt bas en nature et nous avons testé la résistance de 21 de ces lignées en laboratoire. Toutes les lignées testées ont fait preuve de résistance, aboutissant à la suppression de 58 à 100% des larves et 70–100% des dommages aux graines, comparativement à une lignée sensible. Le développement larvaire était retardé et la survie était réduite chez toutes les lignées. Cette antibiose était associée à une réaction hypersensible à la surface de la graine. La réaction d’hypersensibilité ou les dommages causés par l’alimentation par les jeunes larves avant leur mort avaient pour effet de réduire la biomasse de certaines graines résistantes infestées de 28%, comparativement à plus de 60% dans le cas des graines infestées sensibles. Certaines lignées réduisaient également le degré d’infestation, soit en inhibant la ponte, ou alors par résistance, empêchant les larves néonates de s’établir à la surface des graines. Quelques lignées réduisaient aussi le taux d’éclosion des oeufs de l’insecte. Dans les expériences en nature, la résistance a eu la même efficacité au cours de deux étés consécutifs au Manitoba et en Saskatchewan et il y avait toujours une différence du degré d’infestation d’un facteur égal à au moins vingt entre les lignées sensibles et les lignées résistantes. Les larves ne pouvaient pas atteindre la maturité chez certaines lignées résistantes. De grandes parcelles de l’une des lignées résistantes ont produit moins de 1% des larves obtenues sur un blé sensible typique et les larves qui ont survécu n’ont donné que quelques adultes de petite taille. Il s’agit là du premier cas rapporté d’un fort degré de résistance réelle du blé de printemps à la cécidomyiie, résistance qui n’est pas qu’un simple asynchronisme entre l’insecte et le stade sensible de la plante. La composante de l’antibiose de la résistance est à l’heure actuelle en train d’être’ incorporée dans des cultivars prometteurs pour la production dans l’Ouest canadien. [Traduit par la Rédaction]

ABSTRACTThe effect of genetic variation in the glutenin and gliadin protein alleles of Alpha 16, a Canada Prairie Spring (CPS) wheat line, on the dough mixing, bread, and noodle quality properties were evaluated. The presence of a gliadin component (BGGL) and the low molecular weight glutenin subunit (LMW‐GS) 45 found in the selection Biggar BSR were associated with significant increases in dough strength characteristics. The results of the study showed that gliadins, LMW‐GS, and high molecular weight glutenin subunits (HMW‐GS) can influence bread‐ and noodle‐making properties of wheat flour. Genotype‐by‐environment interactions were not significant for most of the quality parameters studied, indicating that the differences observed in quality characteristics were mainly due to the effect of genotype.

Ten spring wheat cultivars possessing identical HMW glutenin subunits (2*, 7+8, 5+10) were evaluated for gluten and protein content. Gluten content was related to flour protein content (r=0·98). Addition of freeze-dried gluten to the base flour (cv Alpha) to a constant protein level of 12% generally increased dough strength. However, the magnitude of variation in mixing patterns depended more on the type of the supplemental gluten. Fortification of the base flour with the freeze-dried gluten from the cv Glenlea produced mixographs with the longest mixing development time (MDT), and highest band width energy (BWE) and energy to peak (ETP), suggesting that the source of gluten had a strong effect on dough rheology. The viscoelastic properties of undiluted wet gluten varied between cultivars during mixing reflecting differences in gluten quality. Freshly prepared wet gluten of Glenlea showed extended mixing tolerance as compared to Norseman or Alpha gluten. The wet gluten from cv Glenlea was less extensible with high maximum resistance to extension and had a larger area under the extensigraph curve than gluten obtained from cv Norseman. Gluten prepared from the cultivars Glenlea, Bluesky and Wildcat were less soluble in aqueous propanol and produced more froth when the dough was washed with deionised water. The froth proteins, separated by SDS-PAGE, predominantly contained strongly stained bands in the region corresponding to molecular weight <50 kDa. The rapid tests such as froth formation and alcohol solubility used in this study to discriminate various glutens were highly correlated with the mixograph parameters. These methods can be of practical value in evaluating gluten quality. © 1998 Society of Chemical Industry.

Four pairs of near-isogenic wheat lines, with and without the 1BL/1RS translocation, and differing at the Glu-1 loci (coding for high molecular weight [HMW] glutenin subunits) were evaluated for their dough mixing properties, dough stickiness, and baking performance. In all 1BL/1RS translocation lines, weakening of the dough consistency occurred within 2 min past peak time. The full-formula dough from every 1BL/1RS translocation line exhibited poor dough mixing characteristics and increased stickiness compared to the corresponding wheat control. The HMW glutenin subunits coded by the Glu-A1 locus had no apparent effect on mixing properties, but did have a slight effect on the dough stickiness at two of the four stages of dough mixing. Glu-B1 and Glu-D1 loci encoded glutenin subunits produced significant changes in dough mixing properties and dough stickiness, respectively. With respect to baking performance, there was no significant difference between loaf volumes of 1BL/1RS versus control wheats for three of four near-isogenic pairs. Within the 1RS-group, the translocation lines containing HMW glutenin subunits 5+10 produced bread with greater loaf volumes than the pairs containing its allelic counterpart 2+12. Loaf volume was not influenced by the subunits associated with the Glu-B1 loci. In general, the breads baked from 1BL/1RS translocation lines had a relatively poor crumb and crust quality and contained larger gas cells than the wheat controls. In comparing isogenic pairs, the magnitude of the difference in loaf volume between the control wheat and the corresponding 1BL/1RS translocation line was greater in the pair unique for HMW subunits 5+10; the difference was primarily due to the stronger mixing properties of the wheat control.

AC Foremost, red-seeded spring wheat (Triticum aestivum L.), combines high grain yield with resistance to prevalent races of common bunt (caused by Tilletia laevis Kuhn in Rabenh. and T. caries (DC.) Tul. & C. Tul.), and loose smut except T9 (caused by Ustilago tritici (Pers.) Rostr. in a semidwarf, photoperiod insensitive background. AC Foremost has improved pre-harvest sprouting tolerance compared with Biggar, AC Taber, and Genesis; improved resistance to leaf rust (caused by Puccinia recondita Roberg ex Desmaz.) and leaf spots (caused by Septoria spp. and Pyrenophora tritici repentis (Died.) Drechs.) compared with Neepawa and Biggar, and earlier maturity compared with Biggar, AC Taber, and Genesis. AC Foremost is eligible for grades of the Canada Prairie Spring (Red) wheat class. Key words: Triticum aestivum L., cultivar description, loose smut resistance, common bunt resistance, high yield, red spring wheat

The objective of this study was to find resistance in wheat cultivars to the wheat midge (Sitodiplosis mosellana [Géhin]). A total of 61 spring and 61 winter wheats were assayed in 1992 to 1994. Thirteen selected cultivars were planted in 1994. Three kinds of apparent response to midge infestation were found. Eight winter wheat cultivars suffered neither the usual typical kind nor high numbers of shrivelling of the seeds often attributed to the midge, but produced instead small numbers of shorter and more rounded (tubby) seeds which could be due to midge activity. Cultivar RL5708 differed from all other cultivars in that it showed low proportions of damaged seeds, which were often associated with dead midge larvae. The third group included lines and cultivars showing the typical shrivelling of the seeds due to the wheat midge. In 1993 most late-planted spring wheat cultivars were less affected by the midge than the same cultivars planted earlier probably because of asynchrony between times of wheat flowering and midge opposition. The incorporation of resistance to the wheat midge into hard red spring wheats should contribute to a reduction of wheat losses in years when wheat midge are abundant. Key words: Winter wheat, spring wheat, wheat midge, Sitodiplosis mosellana, resistance

Fusarium head blight (FHB) of wheat has recently become more prevalent in Manitoba, Canada. The objectives of this study were to assess the pathogenicity of Fusarium species isolated from infected wheat spikes, determine their potential to produce trichothecene mycotoxins and evaluate wheat cultivars for resistance to these Fusarium species. This information is a prerequisite to the development of cultivars with effective resistance to FHB in Manitoba. Eight Chinese and three Canadian wheat cultivars were evaluated against individual strains of seven Fusarium species singly in the field. Severity of FHB was measured as percentage of discolored peduncles and percentage of tombstone kernels. On this basis, Fusarium culmorum and F. graminearum were highly pathogenic, F. sporotrichioides had intermediate pathogenicity, and the other species were weakly pathogenic. For F. culmorum and F. graminearum, FHB severity correlated positively with kernel weight reduction and recovery of Fusarium species from the seed and correlated negatively with seed germination. Fusarium species varied in their ability to produce trichothecenes in infected wheat spikes. Wheat inoculated with F. poae contained both type A and B trichothecenes, while that inoculated with F. culmorum and F. graminearum produced type B only. Wheat inoculated with F. sporotrichioides contained type A trichothecenes, while that inoculated with F. avenaceum contained no detectable trichothecenes. Concentration of DON correlated positively with percentage of tombstone kernels in F. culmorum and F. graminearum, and that of HT-2 toxin correlated positively with percentage tombstone kernels in F. sporotrichioides. Biggar, Katepwa and Sceptre wheats were susceptible to F. culmorum and F. graminearum. High levels of resistance, expressed as low FHB severity combined with low trichothecene production, were found in several Chinese cultivars. These traits could be incorporated in adapted cultivars and be monitored by use of artificial inoculation. Key words:Fusarium culmorum, Fusarium graminearum, fusarium head blight, mycotoxins, resistance, wheat

Anther culturability of 43 cultivars and 6 F1 crosses representing different quality classes of spring wheat was studied using a glucose-containing, modified N6 medium (HNG). Generally high pollen embryoid formation (up to 111 embryoids per 100 anthers) was associated with lower green plant regeneration (up to 9.1 green plantlets per 100 embryoids) frequencies and a high proportion (63% on average) of albino plants. Anther response was found to be strongly affected by the genotype of the donor plants. Seven of the screened cultivars yielded more than one green regenerated plant per 100 anthers. The most responsive cultivars were Veery #2 (6.2), ST 6 (4.0), and Leader (3.6). No ability to regenerate green plantlets was shown by 10 of the genotypes. Anther responsiveness of F1 progenies as compared with the parental cultivars were different in each cross. Differences found between reciprocal crosses suggest that the cytoplasm of a donor plant may affect anther response. Haploid plants constituted 45% of the anther derived regenerants, while the remaining part was divided into 29% of spontaneous diploids and 26% of plants with abnormal chromosome numbers. Key words: Triticum aestivum, anther culture, doubled haploids, wheat

The incidence of fusarium head blight, incited by Fusarium graminearum and other Fusarium species, has been increasing in Manitoba since 1984. Surveys of farm fields were conducted from 1988 to 1991 to assess the prevalence, distribution, and severity of the disease in wheat in Manitoba. Results of the surveys showed that fusarium head blight occurs throughout Manitoba. South-central Manitoba had the highest percentage of infested fields and the highest number of severely affected fields. Hard red spring wheat had severity levels (trace to 40%) similar to those for semi-dwarf common and durum wheats. F. graminearum was the most prevalent species associated with head blight. F. culmorum and F. graminearum were more pathogenic than F. acuminatum, F. avenaceum, F. equiseti, F. poae, and F. sporotrichioides. A field inoculation experiment was conducted to determine the effect of F. graminearum on grain yield, seed quality, and related characters in a susceptible durum wheat cultivar. Averaged over two years, F. graminearum reduced grain yield, 1000-kernel weight, and kernel weight per spike by 32, 34, and 36%, respectively, at 28% severity of fusarium head blight. However, kernel number was not affected. F. graminearum also affected seed quality. Seed infection reduced germination in 1989 and plant emergence and grain yield in 1990. Infected seed was not an important source of inoculum of F. graminearum. The results indicate that fusarium head blight may pose a serious threat in years when conditions are optimal for disease development.