Inheritance of grain protein concentration, grain yield, and related traits in spring wheat (Triticum aestivum L.)

Abstract

The inheritance of grain protein concentration (GPC), grain protein yield (GPY), total nitrogen at maturity (TNM), nitrogen harvest index (NHI), grain yield (GY), total dry matter (TDM), and harvest index (HI) were studied in two spring wheat crosses, 'HY521/UM684' and 'HY521/Sinton' in 1985 at Winnipeg and Portage la Prairie, Manitoba. Analysis of variance of parental performance by location indicated that the parents differed significantly for all traits measured and that genotype by location interactions accounted for less than 8% of the observed variation. Generation means analyses indicated that all traits were primarily under genetic control in both crosses with additive gene action being significant for all traits studied. Dominance gene action was detected for all traits but the degree and direction was both trait and genotype specific. Additive × additive epistasis was significant for GPY, TNM, GY, and TDM, but again, was genotype specific. Variance analyses indicated a large genetic component of the variation relative to the environmental component for all traits studied. F2 broad sense heritabilities were moderately high for GPC (0.57–0.76), GPY (0.57–0.76), TNM (0.56–0.73), NHI (0.39–0.59), GY (0.51–0.70), TDM (0.65–0.79) and HI (0.50–0.67). Narrow sense heritabilities were moderately high for GPC (0.50–0.75) and HI (0.49–0.58) but were somewhat lower for GPY (0.26–0.48), TNM (0.27–0.38), NHI (0.24–0.38), GY (0.27–0.39) and TDM (0.32–0.65). Implications of the results of this study on breeding for simultaneous improvement in GPC and GY are discussed.Key words: bread wheat, heritability, grain protein yield, total nitrogen at maturity, nitrogen harvest index, total dry matter, harvest index, breeding strategies.