稻茬小麦不同栽培模式产量差异形成的群体结构分析

Analysis of the Population Structure for Yield Gap of Wheat after Rice under Different Cultivation Modes

为探究江苏稻茬小麦不同栽培模式下产量差异形成的原因,明确提高产量的调控途径,以小麦品种扬麦25为材料,分别在江苏省扬州市和兴化市两地种植,设置高密无氮(Y0,基本苗300×10^(4)株·hm^(-2),不施氮)、高密高氮(Y1,300×10^(4)株·hm^(-2),施氮300 kg·hm^(-2)),低密中高氮(Y2,150×10^(4)株·hm^(-2),施氮270 kg·hm^(-2))和中密中氮(Y3,225×10^(4)株·hm^(-2),施氮240 kg·hm^(-2))4种栽培模式,对不同栽培模式下小麦产量和群体结构的差异进行了分析。结果表明,扬州和兴化试验点产量均表现为Y3>Y1>Y2>Y0,其中Y3与Y1及Y1与Y2模式的平均产量差值分别为434.54和312.82 kg·hm^(-2)。经通径分析,穗数差和粒重差是导致模式间产量差形成的主要原因。相关分析表明,乳熟期叶面积指数差、开花至乳熟期绿叶面积持续时间(LAD)差与产量差均呈显著正相关,花后干物质积累量差、孕穗至开花期绿叶面积持续时间差与产量差均呈极显著正相关。总体来看,基本苗225×10^(4)株·hm^(-2)施氮量240 kg·hm^(-2)基肥∶壮蘖肥∶拔节孕穗肥为5∶1∶4的栽培模式能够使稻茬小麦保持花后较高的叶面积指数和绿叶面积持续期,提高花后干物质积累量,是缩小产量差的主要调控途径。

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^(4)plants·hm^-(2),no nitrogen application),high density and high nitrogen mode(Y1,300×10^(4)plants·hm^(-2),nitrogen application amount of 300 kg·hm(-2)),low density and medium to high nitrogen mode(Y2,150×10^(4)plants·hm(-2),nitrogen application amount of 270 kg·hm(-2)),and medium density and medium nitro gen mode(Y3,225×10^(4)plants·hm^(-2),nitrogen application amount of 240 kg·hm^(-2).The resultsshowed that:the yield of Yangzhou and Xinghua ranked as Y3>Y1>Y2>Y0.The average yieldgap 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 leadingto yield gap among the four modes.Correlation analysis showed that there was a significant positivecorrelation between the gap of LAI at milking stage and green leaf area duration(LAD)from floweringto milk gap and yield gap,and a extremely significant positive correlation between dry matter accumu-lation 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^(4) plants·hm^(-2),nitrogen application amountof 240 kg·hm^(-2) and nitrogen application ratio of 5∶1∶4 at the stages of basal,tillering and jointingkept higher LAI,higher LAD,and increased dry matter accumulation after flowering,which was themain regulation approach to reduce yield gaps of wheat after rice.