An Analysis of Post‐Anthesis Sink‐Limited Winter Wheat Grain Yields Under Various Environments1

Abstract

AbstractBetter understanding of the frequency of post‐anthesis sink‐limited winter wheat (Triticum aestivum L.) grain yields is needed in selecting genotypes with high yield potential and yield stability. Field studies were conducted at four locations (the major soil types were mesic, Aridic Paleustolls and mesic, Aridic Argriustolls) in eastern Colorado over the two cropping seasons of 1976–1977 (1977) and 1977–1978 (1978), using yield and yield component analysis, to determine the effect of sink limitations. Three hard red winter wheat cultivars were grown under four N fertilizer rates at each location to increase variation in grain yield and yield components. Variation was observed for grain yield and the yield components of spike no. (spike no. m−2), kernel no. per spike, kernel no. (kernel no. m−2), and kernel size (mg kernel−1) across locations. Grain yield and yield component variation, due to cultivars or N treatments, were observed at six of the eight sites. Variation in grain yield within and across sites was more consistently correlated with kernel no. than kernel size. These results strongly suggest that wheat grain yields may be sink‐limited during grain filling over a wide array of environments. Variation in kernel no. within locations was more consistently correlated with kernel no. per spike than spike number, while variation in kernel no. across locations was more highly associated with spike no. than kernel no. per spike. Thus, both yield components were important in establishing sink capacity under the variable environmental conditions of this study.