Validation of the effects of the Gpc-B1 high grain protein concentration locus from Lillian hard red spring wheat (Triticum aestivum L.) using locus specific markers

Abstract

Wheat grain protein concentration (GPC) is negatively associated with economic grain yield (GY) hindering attempts to improve these traits simultaneously. Studies indicate the incorporation of the Gpc-B1 high grain protein gene from emmer wheat into commercial wheat cultivars improves grain quality and nitrogen use efficiency with little effect on GY. Molecular markers are helpful in tracking such genes in breeding lines. Our objectives were to study the cultivar Lillian which has Xucw71 and Xuhw89 marker molecular variants commonly associated with Gpc-B1, in order to (1) validate the efficacy of the genetic markers for selecting Gpc-B1 associated with high GPC from Lillian, and (2) assess the effect of the presence of the DNA segment linked to these markers on GPC, GY and yield related traits in genetic populations. Four genetic populations deriving from the Gpc-B1 donor Lillian were developed and partitioned using markers Xucw71 and Xuhw89 into two groups of lines, one group bearing homozygous Gpc-B1 (M+) and the second the homozygous null (M−) allele. Field tests were conducted at Swift Current and Stewart Valley, Saskatchewan, and Lethbridge, Alberta over 2 years. Gpc-B1 significantly influenced GPC, GY, thousand kernel weight (TKW) and test weight, but its effect on plant maturity was inconsistent showing variable effects in different populations and environments. Significantly higher GPC (P ≤ 0.0001) was detected in lines with the M+ than the M− allele. Genetic markers Xucw71 and Xuhw89 were effective in discriminating Gpc-B1 from Lillian confirming their value in marker assisted breeding.