Comparison of Morphological and Genetic Differentiations in Filial Generation of Cross Between Indica and Japonica Rice

A recombinant inbred line (RIL) population of F8 and F9 generations derived from a cross between a typical indica rice (Qishanzhan) and a typical japonica rice (Akihikari) was used to study the difference between morphological differentiation based on phenotype characters and genetic differentiation using indica and japonica specific SSR markers, and to evaluate the relationship between vascular bundle characters and morphological and genetic differentiations. The results showed that the frequency distributions of morphological and genetic differentiations were all inclined to japonica type in the filial generation. The population was more inclined to japonica type based on genetic differentiation than on morphological differentiation. The consistent degrees of classification based on the Cheng's index, the ratio of large vascular bundle number to small vascular bundle number in panicle neck (RLSVB) and the ratio of large vascular bundle number in the second internode from the top to that in the panicle neck (RLVB) were all about 50% compared with the genetic differentiation, and the consistent degree of the total scores of the Cheng's index combined with the vascular bundle number ratios was significantly increased to about 80% compared with the genetic differentiation. Therefore, the vascular bundle characters could be used as a helpful supplement for subspecies classification.