Abstract: Grain shape of paddy rice, including length width, thickness and ratio of length to width were quantitative traits controlled by polygene. The most of the traits in crosses were mainly controlled by additive genetic effects and had higher genetic advance and the range of their heritabilities in broad and narrow-sense were 28.3%-94.0% and 4.0%-83.2%, respectively. There were closely relationships among grain length, grain width and ratio of length to width. Paddy grain length and ratio of length to width could be improved with heavier panicle and more panicles in higher selecting pressure. Using above methods of selection, Zhenong 928 and Zhenong 937 with preferable paddy grain shape and yield potential have been bred.

Key words: breeding, grain shape, indica rice, inheritance

摘要： 谷粒的长度、宽度、厚度、长宽比和粒重都属于多基因控制的数量性状。多数组合或性状是以加性效应为主，广义和狭义遗传率分别为28.3%～94.0%和4.0～83.2%，并有较高的遗传进度。粒长、粒宽与长宽比间的相关最为密切。加强杂交后代长粒形的选择压，并注意穗重和穗数可明显改进粒长和长宽比。通过上述选择方法已初步育成细长粒高产品系浙农928和浙农937。

关键词: 育种, 粒形, 籼稻, 遗传