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The recombinant inbred lines (RILs) population derived from the cross between "Zhongyouzao8" (hsien or indica) and "Fengjin" (keng or japonica) was grown in Liaoning and Sichuan Provinces to compare the subspecies characteristics under different environments. The results showed that the distribution of Cheng's index was japonicalinous. The population was more japonicalinous in Sichuan than that in Liaoning as a whole. Further analysis indicated that indica and indica-cline in Sichuan were more indicalinous than those in Liaoning, japonica and japonica-cline in Sichuan were more japonicalinous than those in Liaoning. The effects of environment on six characteristics of Cheng's index were different because of different characters, as well as on the correlations between the six characters, the Cheng's index and the vascular bundle traits. For example, the length of the first and second rachis and leaf pubescence were more japonicalinous in Sichuan than in Liaoning, while the length/ width ratio of spikelets and glume color at heading time were more indicalinous in Sichuan than in Liaoning. The vascular bundle characteristics of RILs in different environments changed remarkably. The number of large vascular bundles in panicle neck was less in Sichuan than in Liaoning, while the number of small vascular bundles in panicle neck and second top stem was greater in Sichuan than in Liaoning. The ratio of large to small vascular bundles in panicle neck decreased and the ratio of large vascular bundles between the second top stem and panicle neck increased in Sichuan. Though total trend was the vascular bundle ratio of large to small in indica was greater than that in japonica and the ratio of large vascular bundles in indica was less than that in japonica, it is not appropriate that the vascular bundle ratio of large to small and the ratio of large vascular bundles are regarded as the parameters for subspecies classification in rice. The vascular bundles characteristics from typical indica or japonica were recombined in the population derived from indica and japonica crossing.Keywords rice, environment, cross between indica and japonica rice, subspecies classification of indica and japonica rice Front.

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Two recombinant inbred lines (RILs) populations, RILSA derived from the cross between "Zhongyouzao8" (indica) and "Toyonihiki" (japonica) rice cultivars, and RILSB derived from the cross between "Qishanzhan" (indica) and "Akihikari" (japonica) rice cultivars, were grown in Liaoning and Sichuan Provinces, China to understand the effects of ecological environments on the subspecies characteristics and economic traits in filial generations of cross between indica and japonica. The results showed that both the subspecies characteristics and economic traits changed significantly. The effects of ecological environments on Cheng's index and six subspecies characteristics were different on the basis of populations or characteristics. The distribution of Cheng's index in RILSA was japonicalinous in Liaoning and Sichuan. The distribution of Cheng's index in RILSB approached to normal distribution in Liaoning, but it was japonicalinous in Sichuan. As a whole, the two populations were more japonicalious in Sichuan than in Liaoning. The panicle number, seed setting rate and per-thousand-grain weight were decreased significantly in Sichuan. The grain number per panicle showed no significant change. A significant positive correlation was found between Cheng's index and the economic traits, including six subspecies traits. It suggested that the reason that the filial generation of cross between indica and japonica in northern China showed japonicanous subspecies characteristics might be the artificial selection by breeders on the economic traits. In addition, indica-japonica differentiation and the relationship with ecological environments were discussed.