Influences of sowing date on grain filling characteristics and yield of winter wheat with different genotypes

Based on field tests and laboratory analysis,the influences of sowing date on grain filling treat,quality and yield of winter wheat with three different genotypes were studied.The results showed that:the grain dry weight of three cultivars of winter wheat under the early sowing treatment reached higher peak than that under the late sowing treatment.The change trend of all cultivars in grain filling rate displayed a curve with single peak.Among which,the early grains of the cultivars'Jimai 20'and'Yumai 49'under the early sowing treatment had lower filling rate and the late grains had higher filling rate,while the cultivar 'Zhengmai 004'always presented higher filling rate of early grains and lower filling rate of late grains,but no significant difference was found.The panicle per unit area,grain number per panicle,1000-grain weight and yield of all cultivars decreased with putting off sowing date.