Soft winter wheat outyields hard winter wheat in a subhumid environment: Weather drivers, yield plasticity, and rates of yield gain

Abstract

AbstractDespite the proximity in zones of adaptation for soft and hard winter wheat (SWW and HWW; Triticum aestivum L.), agronomic evaluations have been confined to market class. Our objectives were to compare SWW and HWW regarding yield and agronomic attributes; genotype, environment, and their interaction; and rates of yield gain. Yield, grain volume weight, heading date, and plant height were collected from 40 adjacent studies evaluating HWW and SWW cultivars in 20 Kansas environments (n = 2,885). Growing season weather partially explained the variability in yield (47–51%), heading date (58–92%), and plant height (67–80%). Yield was greater in SWW than in HWW (3.73 vs. 3.48 Mg ha−1), and a quadratic relationship between the 10th, mean, and 90th percentile yields suggested that SWW has a greater yield potential than HWW, although grain volume weight was greater in HWW (743 vs. 733 kg m−3). An asymmetric yield response for both classes was associated with greater phenotypic plasticity, which portrayed a more positive response for SWW. We performed a literature review that suggested a greater genetic gain for SWW than for HWW (33 vs. 17 kg ha−1 yr−1). This gain, however, represented a smaller portion of the regional yield gain (considering both genetic gain and adoption of agronomic practices) of each class (72 vs. 81%). We concluded that SWW outyields HWW due to greater rates of genetic gain, partially due to breeding in higher yield environments, and more positive phenotypic plasticity of yield in high‐yielding environments coupled to yield stability in excessively moist environments.