Differential responses of grain yield, grain protein, and their associated traits to nitrogen supply in soft red winter wheat. Issue 3 (28th March 2017) - Tamang, Bishal G.
Abstract: Increased application of nitrogen fertilizers has significantly raised grain yield and protein concentration in wheat. However, only 30–50% of applied fertilizer nitrogen are usually utilized by the plant. In this study, four soft red winter wheat genotypes ( Triticum aestivum L., IL07‐4415, MD05W10208‐11‐8, OH06‐150‐57 and Sisson) were grown under three different nitrogen regimes (high, medium, and low) in a greenhouse, and grain yield, grain protein concentration, nitrogen use efficiency (NUE) and their associated traits were evaluated. Among the four genotypes, a high‐yielding cultivar, Sisson, exhibited superior performance in terms of grain weight plant −1 and NUE for yield (NUEY) at low nitrogen due to maintained grain number spike −1 and harvest index. Significant yield losses due to nitrogen limitation were attributable to reduced spike number plant −1 and grain number spike −1 in the other genotypes. Interestingly, a linear relationship between NUEY and NUE for grain protein (NUEP) was detected at high ( R 2 = 0.67) and low ( R 2 = 0.42) nitrogen; both of these traits were positively correlated with grain number spike −1, 1000‐seed weight, and harvest index under nitrogen‐limited conditions ( R 2 = 0.35–0.48). These results suggest that simultaneous improvement of NUEY and NUEP could be achieved through the selection of the three yield components (grain number spike −1, 1000‐seed weight, and harvest index) at low nitrogen.