两种穗型品种粒重和结实率在穗上不同粒位的分布差异

为了探索不同穗型品种米质差异形成的原因,研究了3个直立穗型和3个弯曲穗型粳稻品种,两种不同穗型水稻穗上不同粒位籽粒粒重和结实率的差异。结果表明:直立穗型品种和弯曲穗型品种的穗部性状差异明显,穗型特征与品种间的粒重和结实率高低没有较大联系,因品种而异。同一稻穗内不同籽粒间的粒重和结实率高低与其颖花在穗上的开花顺序有密切联系;不同部位间籽粒相比,粒重和结实率基本都表现为上部中部下部;不同枝梗间相比表现为一次枝梗二次枝梗;同一枝梗不同着粒部位相比,一次枝梗上6个粒位籽粒的粒重和结实率基本以第4、5、6粒位较高,第2粒位最低,二次枝梗上3个粒位以第1粒位最高,第2粒位最低。一次和二次枝梗与上部、中部和下部枝梗这两类粒位之间的互作对粒重有显著影响。直立穗型品种单一稻穗不同粒位间粒重和结实率的变异大于弯曲穗型品种。

Difference Analysis on Grain Weight and Seed Setting Rate of Different Grain Positions at Panicle Between Two Panicle Types of Japonica Rice

In order to explore the formation causes of rice quality differences of different panicle varieties, taking three japonica varieties with erect panicle and three with curved panicle as materials, the differences of grain weight and seed setting rate between different grain positions of two panicle types were analyzed. The results showed that the difference of panicle traits between erect panicle type and curved panicle varieties was obvious; panicle types had no direct correlation with varieties for grain weight and seed setting rate. The variation in grain weight and seed setting rate of grains at the different positions within a panicle was closely related to the flowering order of rice grains on the rachis branches. Generally,grain weight and seed setting rate on the bran- ches at the upper part of a panicle exhibited the greatest,at the middle part the middle,and at the basal part the least. Grain weight and seed setting rate for the grains on a primary branch were greater than those on a sec- ondary branch at the same part of a panicle. Grain weight and seed setting rate for the grain 4,5 and 6 on the primary branch showed the highest,the grain 2 showed the lowest. Grain weight and seed setting rate were the least for the second grain and the greatest for the first grain on a secondary branch within a panicle. The signifi- cant difference was found in grain weight among grains located on different rachises（primary and secondary ra- chises）and panicle position（top,middle and bottom） of rice. The variation in grain weight and seed setting rate of grains at the different positions within a panicle in erect panicle type varieties was greater than that of the curved panicle type varieties.