RECURRENT SELECTION FOR GRAIN PROTEIN IN HARD RED SPRING WHEAT

Grain protein concentration (GPC) of bread wheat (Triticum aestivum L.) is important because it partially determines bread-making properties and nutritional value of wheat hour. Ten hard red spring wheats selected for high GPC and other traits were intermated to form the initial population. Twenty to 25 F-3 lines were selected and recombined to initiate each successive cycle. Selection intensity for the parents of each cycle ranged from 3.5 to 8%. Four cycles of recurrent selection for increased GPC were evaluated. Direct response to selection for GPC and indirect responses of agronomic and breadmaking quality traits were determined, About 50 random F-3-derived lines from Cycles 0, 2, and 4 were evaluated at two locations for 2 yr to provide an estimate of gain from selection. The average realized gain for GPC was 2.7% per cycle of selection. Flour protein concentration, mixogram water absorption, and kernel hardness increased Linearly with selection for GPC. Although recurrent selection effectively increased GPC linearly over cycles, this gain was associated with lower grain yield. We observed a linear decrease in grain yield of 3.2% per cycle at the target location, but no linear trend was detected at the other location. Lines which combine high GPC and high grain yield may be useful as germplasm sources.