Tillering Characteristics and Its Relationships with Yield Components of Mechanical Direct-seeding Rice at Different Sowing Date

[Objective] The research aimed to explore the tillering characteristics of mechanical direct- seeding rice at different seeding date in field production.[Method]The rice variety was Huaidao 5,the methods of combining investigating the typical rice field with the experiment was used to study the effects of different sowing date on tiller emergence,panicle characteristics and yield of mechanical direct- seeding cultivation methods.[Result]Sowing early at suitable date,panicle number per plant was more,and the main tillering zone was located between from leaf 2 to leaf 4 and good characters were observed for the panicles developed from these leaves. Although the panicle number of leaf 1 had a big proportion in the composition of a tiller spike,the panicle traits were bad and made little contributions to the yield. Along with the delayed sowing date,panicle number per plant was low,and the number of superior leaf position was less,on June 15 only leaf 2 and leaf 3 were the superior positions for tiller emerging and panicle formation,had better panicle traits and made great contributions to the yield. The leaf 4 and leaf 5 were inhibited very significantly.[Conclusion]Mechanical direct- seeding rice should be sown early at the suitable date( before June 5) in Haifeng area. It was of great significance to enhance the leaf 2 to leaf 4 tillers' emergence and flowering frequency,explore the way to increase yield potential of the superior leaf position through proper management measures to achieve high and stable yield of mechanical direct- seeding rice in Haifeng area.