There was a great direct positive effect of grains per panicle on seed set in IJv hybrids.The increase of seed set of IJv hybrids mainly depended on more grains per panicle.

• 每穗实粒数对籼爪交杂种结实率的直接正效应大，籼爪交杂种结实率的提高主要依赖每穗实粒数的增加，而其它性状的选择和改良作用不大。