| In order to explore the causes of yield gap under different cultivation modes of wheat after rice in Jiangsu Province,and to clarify the regulation methods for increasing yield,a wheat variety Yangmai 25 was planted in Yangzhou and Xinghua of Jiangsu Province. Four cultivation modes were set up in both two sites,including high density and nitrogen free mode(Y0,300×10 plants·hm-2,no nitrogen application),high density and high nitrogen mode(Y1,300×10 plants·hm-2,nitrogen application amount of 300 kg·hm-2),low density and medium to high nitrogen mode(Y2,150×10 plants·hm-2,nitrogen application amount of 270 kg·hm-2),and medium density and medium nitrogen mode(Y3,225×10 plants·hm-2,nitrogen application amount of 240 kg·hm-2). The results showed that:the yield of Yangzhou and Xinghua ranked as Y3 > Y1 > Y2 > Y0. The average yield gap between Y3 and Y1 was 434.54 kg·hm-2,and that between Y1 and Y2 was 312.82 kg·hm-2,respectively. Path analysis showed that spike number and grain weight were the main reasons leading to yield gap among the four modes. Correlation analysis showed that there was a significant positive correlation between the gap of LAI at milking stage and green leaf area duration(LAD) from flowering to milk gap and yield gap,and a extremely significant positive correlation between dry matter accumulation gap after anthesis and LAD gap from booting to flowering stage and yield gap. These results indicated that the cultivation mode of the density at 225×10 plants·hm-2,nitrogen application amount of 240 kg·hm-2 and nitrogen application ratio of 5∶1∶4 at the stages of basal,tillering and jointing kept higher LAI,higher LAD,and increased dry matter accumulation after flowering,which was the main regulation approach to reduce yield gaps of wheat after rice. |
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