Preliminary analysis of the hybrids with smaller panicle in the system of rice intensification.

Grain yield and yield component traits of 18 rice hybrids were evaluated under the system of rice intensification(SRI) and traditional cultivation(CK).The increasing yield effect of SRI to CK was very significantly and negatively correlated with the grains per panicle of hybrids.The hybrids with smaller panicle had positive yield effect under SRI because the grains per panicle and total number of spikelets increased.The hybrids with bigger panicle under SRI,however,showed negative yield effect due to largely declining in effective panicle and seed set percentage.A suggestible criterion is that the hybrids with grains per panicle less than 170 in CK,may more be suitable to SRI.The relation between soil fertility level and SRI effect was also investigated.