Contribution of kernel size to grain yield potential and sample uniformity of winter wheat

Non-Peer ReviewedImprovements in agronomic practices and cultivars have permitted the successful production of winter wheat on the Canadian prairies. In this study, the seed size of eleven winter wheat varieties grown under dry land and irrigation in each of two years was measured to determine if kernel size and position in the spikelet were important restrictions to cultivar grain yield potential and sample uniformity. Varietal differences in the weight of kernels in the A and B positions in the spikelet varied by more than 20 percent indicating that there is considerable genetic variation available in the wheat gene pool for this character. Kernel size of the C and D positions decreased to approximately 75 and 50 percent, respectively, of the average A and B positions in both dry land and irrigation environments. Artificially reducing floret numbers by 25 and 50 percent to increase assimilate supply to the remaining seeds did not influence seed size under irrigation. In contrast, kernel weight increased as the number of spikelets spike-1 decreased indicating that assimilate supply during grain filling and not restrictions imposed by kernel size determine grain yield of winter wheat grown on dry land in western Canada