High-temperature adult-plant (HTAP) stripe rust resistance gene Yr36 from Triticum turgidum ssp. dicoccoides is closely linked to the grain protein content locus Gpc-B1

Abstract

Several new races of the stripe rust pathogen have become frequent throughout the wheat growing regions of the United States since 2000. These new races are virulent to most of the wheat seedling resistance genes limiting the resistance sources that can be used to combat this pathogen. High-temperature adult-plant (HTAP) stripe rust resistance has proven to be more durable than seedling resistance due to its non-racespecific nature, but its use is limited by the lack of mapping information. We report here the identification of a new HTAP resistance gene from Triticum turgidum ssp. dicoccoides (DIC) designated as Yr36. Lines carrying this gene were susceptible to almost all the stripe rust pathogen races tested at the seedling stage but showed adult-plant resistance to the prevalent races in California when tested at high diurnal temperatures. Isogenic lines for this gene were developed by six backcross generations. Field tests in two locations showed increased levels of field resistance to stripe rust and increased yields in isogenic lines carrying the Yr36 gene compared to those without the gene. Recombinant substitution lines of chromosome 6B from DIC in the isogenic background of durum cv. Langdon were used to map the Yr36 gene on the short arm of chromosome 6B completely linked to Xbarc101, and within a 2-cM interval defined by PCR-based markers Xucw71 and Xbarc136. Flanking locus Xucw71 is also closely linked to the grain protein content locus Gpc-B1 (0.3-cM). Marker-assisted selection strategies are presented to improve stripe rust resistance and simultaneously select for high or low Gpc-B1 alleles.

Review Article: High-Temperature Adult-Plant Resistance, Key for Sustainable Control of Stripe Rust

“…Three-QTL controlled HTAP resistance was reported in wheat cultivar Express [52]. In addition, the recently cloned Yr36, a single-gene or QTL conditioning HTAP resistance was reported in wheat genotypes transgressed from Triticum dicoccoides [31,32]. Similarly, the Yr18 conditioning stripe rust resistance we considered as HTAP resistance was also recently cloned as the same gene as Lr34 for durable resistance to leaf rust [60].…”

“…The 2-way testing would include high-temperature resistance, which also expresses in the seedling stage, but may eliminate plants with adult-plant resistance expressing only at low temperatures. The recently cloned Yr36 was classified as HTAP resistance based the 2-way testing [31], but was late identified more accurately as temperature-sensitive resistance using the 4-way testing [32]. Under field conditions, temperature-sensitive resistance mainly express in the adult-plant stage because temperatures are usually low in the early crop season, which does not allow high-temperature resistance to express.…”

Rapid linkage disequilibrium decay in the Lr10 gene in wild emmer wheat (Triticum dicoccoides) populations

“…The natural habitats of T. dicoccoides are located in the Middle East Fertile Crescent. T. dicoccoides populations harbor a valuable pool of resistance genes that can be transferred into cultivated wheat (Rong et al 2000;Knott et al 2005;Mergoum et al 2005;Uauy et al 2005;Marais et al 2005;Gustafson et al 2009). Numerous studies of T. dicoccoides genetic diversity have shown that the population in…”

A review of wheat cultivars grown in the Canadian prairies

“…The Canada Western Hard White (CWHW) class was introduced in 2001 to accommodate market opportunities for white-seeded wheat with end-use suitability more similar to CWRS, and launched with the cultivars Snowbird (Humphreys et al 2007b) Winter hexaploid wheat (T. aestivum L.) differs from spring wheat by genes that control response to a vernalization requirement (Worland and Snape 2001) and generally for cold tolerance (Fowler and Gusta 1979;Thomas et al 1988). Winter wheat has been grown in Canada from the early 1600s by settlers in Atlantic Canada and Quebec and represents the majority of the wheat production in eastern Canada.…”

“…Resistance to stripe rust has been incorporated into some of the CWSWS cultivars, such as AC Reed (Sadasivaiah et al 1993), since they were developed for production in southwest Alberta. Most cultivars in the other classes are relatively susceptible, except for those that carry Lr34 and the completely linked stripe rust resistance gene Yr18 and Yr36 linked to Gpc-B1 (Uauy et al 2005).…”