“油-稻-稻”三熟制氮高效早稻品种的筛选

Selection of High Nitrogen Efficient Early Rice Varieties under“Rapeseed-Rice-Rice”Cropping System

【目的】筛选出适宜“油-稻-稻”三熟制的氮高效早稻品种的简易判断方法。【方法】利用田间小区试验,选用生育期适宜“油-稻-稻”三熟制的15个早稻品种,进行施氮(N1)和不施氮(N0)处理。研究不同早稻品种的氮素表观吸收率(REN),并以欧式距离长短进行聚类,分成3种氮效率类型,并逆向溯源出3种氮效率类型品种在不同氮水平条件下的主要农艺性状、产量形成、茎蘖成穗、氮素吸收利用等方面的表现特征。从而总结分析出氮高效早稻品种的一些简易判断的特征。【结果】15个早稻品种按REN不同分成高、中、低3种类型,不同氮效率品种存在显著差异。N1处理下成熟期早稻品种的主要农艺性状的表型值和变异系数基本表现大于N0处理。因此,以N1处理下不同品种的农艺性状表现作为不同氮效率品种的鉴别标准。N1处理下,氮高效品种比其他2种类型的品种产量高、穗数多、成熟期剑叶SPAD值高、千粒质量大、高峰苗期3叶以上高效分蘖比例大、成穗率高、氮素积累量、吸氮量和氮收获指数均较高。【结论】在正常施氮水平下,成熟期剑叶高SPAD值、多穗、高成穗率、高千粒质量、高产量等可以作为简易判断适宜“油-稻-稻”三熟制的氮高效早稻品种的指标。

[Objective]To select a simple method to determine high nitrogen efficient varieties of early rice suitable for“rapeseed-rice-rice”triple-cropping system.[Method]In the field plot experiment,15 early rice varieties suitable for the“rapeseed-rice-rice”triple-cropping system were selected under the nitrogen(N1)and no nitrogen(N0)treatments.Their apparent recovery efficiency of applied nitrogen(REN)was studied,and clustering analysis was carried out based on Euclidean distance length.The 15 rice varieties were divided into three types(high REN,middle REN and low REN)of nitrogen efficiency according to their different REN.The performance of the main agronomic traits,yield and its formation,tiller and ear bearing characteristics,nitrogen absorption and utilization of the three types of rice varieties under different nitrogen levels were observed.And the simple characteristics to judge the high nitrogen efficiency were summarized[.Result]The 15 early rice varieties were divided into high,middle and low types according to REN,different nitrogen efficient varieties had significant differences.The phenotypic value of the main agronomic traits and the coefficient of variation at the maturity stage of the early rice varieties under the N1 treatment were higher than those under the N0 treatment.Thus,the characteristics of the rice under the N1 treatment could be used as the identification standard for the different nitrogen efficient varieties.Under the N1 treatment,compared with the middle and low nitrogen efficient varieties,the high nitrogen efficient varieties had higher grain yield,more ears,higher SPAD value of the flag leaf,higher 1000-grain weight,more 3 leaves above tillers at the peak seedling stage,higher earing-bearing rate,higher nitrogen accumulation,higher nitrogen uptake and higher nitrogen harvest index[.Conclusion]Under the normal nitrogen level,the high SPAD value of the flag leaves,more ears,high ear bearing rate and high 1000-grain weight at the mature stage and high grain yield can be used as simple selecting indexes for high nitrogen efficiency early rice varieties suitable for the“rapeseed-rice-rice”triple-cropping system.