LAUSR

The irrigating winter wheat one or two times each season was practiced in Huanghuai Winter Wheat Region in order to reduce the over-exploitation of groundwater. In this study, plant height (PH) and its relationship with yield were analyzed in a field study conducted over three growing seasons with 102 wheat varieties irrigated zero to two times at different growth stages. Here, we found that irrigation at the jointing stage increased wheat PH by 6.60–9.70%. Whereas irrigation at the early milking stage had almost no effect on it. Against the wildtype alleles Rht-B1a and Rht-D1a , the genetic background of Rht-B1b and Rht-D1b significantly reduced PH by 14.40–15.50% and 16.90–19.10%, respectively. The combined Rht-B1b and Rht-D1b can reduce PH by 29.10–32.50%. PH was strongly, negatively correlated with grain yield in jointing irrigation (W1) or jointing + milking irrigation (W2) over three growing seasons. In contrast, a significant positive correlation was detected in no-irrigation (W0) in the 2012/2013 wheat growing season, yet no correlation was found in 2013/2014 and 2014/2015. PH was positively correlated with drought coefficient (DRC) in W1 and W2. These results augment our understanding of the relationship between PH and grain yield in different irrigation regimes and provide PH traits for wheat improvement on water saving.