Subspecies Characteristics and Their Relationships with Economic Characters in Rice

The Cheng's Index Classification Method was used to study rice characteristics.The results showed as follows:95 rice varieties developed from Indica×Japonica could be classified into the Japonica type or preferential Japonica type.Among the 6 characteristics of subspecies,the color of spike,phenol reaction,pubescence of chaff,pubescence of leaf,and the ratio of grain length to grain width,all or most of them performed typically as those of Japonica,a few as middle type or Indica.In the length of panicle node,most of the varieties performed as middle type,few as Indica and Japonica.There was no close relation on Cheng's Index,characteristics of subspecies and economical traits in the F 1 of Indica×Japonica and varieties from the combination,but the relationships became closer in the F 2 generation.The vascular bundles ratio of large to small and the percentage of large vascular bundles were regarded as the parameters for subspecies classification of rice.