杂交籼稻组合演替过程中植株农艺性状的变化

Changes in Agronomic Traits of Indica Hybrid Rice During Genetic Improvement

以大面积推广的23个杂交籼稻组合为材料,研究了品种更替过程中农艺性状的演变特征。结果表明,在杂交籼稻组合的演替过程中,单株有效穗数下降,单株产量和生物量降低,单茎的茎鞘、叶片、穗重增加,抽穗后叶片的光合能力增强。相关分析和通径分析表明,生物量是影响单株产量的主要因素。在杂交稻的育种和栽培中,强调单个有效穗的大穗优势的同时,必须注重品种的分蘖发生能力,建立适宜的群体密度以获取高产。

In order to elucidate the changes of agronomic traits during genetic improvement,23 typical indica hybrid rice combinations applied in the production in the middle and lower reaches of the Yangtze River during the last 30 years were used.All the hybrid rice combinations were grown in the same field,yield and morphological characters of single plant were compared,and correlation and path analyses among agronomic characteristics were conducted.During the 30 years of genetic improvement,the effective panicle number per plant was progressively decreased,which caused the decrease of grain yield and biomass per plant of hybrid rice combinations in spite of the slightly increased plant height,1000-grain weight and number of grains per panicle.Although the transformation percentage of the matter in stem and sheath decreased after flowering,leaf photosynthetic capacity after flowering increased as well as panicle weight.Correlation and path analyses showed that although both biomass per plant and number of grains per panicle were significantly correlated with grain yield per plant,biomass per plant acted as the key factor affecting yield per plant.It is suggested that in rice high yield cultivation,panicle number was as important as large panicle,and tillering ability should not be neglected in breeding.