Belt Uniform Sowing Pattern Boosts Yield of Different Winter Wheat Cultivars in Southwest China

The relationship between the sowing patterns and yield performance is a valuable topic for food security. In this study, a novel belt uniform (BU) sowing pattern was reported, and a field experiment with four winter wheat cultivars was carried out over three consecutive growing seasons to compare the dry matter accumulation, harvest index (HI), grain yield and yield components under BU and line and dense (LD) sowing patterns [BU sowing with narrow (15 cm) spacing; BU sowing with wide (20 cm) spacing; LD sowing with wide (33.3 cm) row spacing; LD sowing with narrow (16.6 cm) row spacing]. Four cultivars produced a higher mean grain yield (GY), above-ground biomass (AGB) and spike number (SN) per m(2) under the BU sowing patterns than the LD sowing patterns in all three growing seasons. However, yield stability under the BU sowing patterns did not increase with the improved grain yield. The HI did not change with sowing patterns, and the contribution of above-ground biomass to grain yield (84%) was more than 5-fold higher than that of HI (16%). Principal component and correlation analyses indicated that the grain yield was positively correlated with the aboveground biomass and SN, while the HI and 1000-grain weight were not correlated with grain yield. We concluded that (1) the novel BU sowing patterns achieved a higher yield potential in winter wheat but did not further improve yield stability; (2) increasing the dry matter accumulation without changing the HI drove improvements in the SN and grain number per spike, thus increasing grain yield.