摘要： 连续三年对66个水稻品种考种分析发现，水稻品种间一次枝梗数及其着粒数差异不大，二次枝梗数差异大，而着粒数较稳定。每穗粒数与一、二次枝梗数密切相关。二次枝梗数对每穗粒数和空秕率的增加起主导作用，一次枝梗数对空秕率有一定的抑制作用。每穗空秕率与二次枝梗数有关，还与品种的遗传特性有关。由于二次枝梗籽粒有两段灌浆现象，如遇不利因素，可导致空秕率增多。增加单位面积总粒数，保持较高结实率，在一定范围内增加每亩穗数已是水稻大面积丰产栽培的一条重要途径。因此，育种工作者可将一次枝梗着粒较多，二次枝梗空秕率较低的穗型作为选择高产品种的形态指标。

关键词: 稻穗, 一次枝梗, 二次枝梗, 结实, 灌浆

Abstract: It was discovered from studies on 66 varieties in 3 successive years that among these varieties the variance was not significant in the number of first panicle branches and the number of seeds,but the variance was significant in the number of secondary panicle branches,though the number of seeds was rather stable.The seed number per ear was closely correlated with the first and secondary panicle branches.The secondary branches were responsible for the increase of seed number per ear and the percentage of sterile grain as well.The first branches had some repressive effects on the sterile grain rate.The sterile grain percentage of an ear was related with the number of secondary branches,and the hereditary characters of the variety.Owing to two sections of filling phenomena in the secondary branches,it may lead to a higher sterile grain rate.if some unfavorable factors happen.To a certain extent,in order to increase the total number of grains per aeit area,increasing ears per mu and keeping a higher seed-setting rate are important in high-yield rice cultivation in a vast area.Hence,the ear type of more seeds on the first panicle branches and fewer sterile seeds on the secondary branches can be used as a morphological characteristic index in selecting high yield varieties by rice breeders.

Key words: Rice ear, First panicle branch, Secondary panicle branch, Seed setting, Filling