Abstract:

【Objective】 The purpose of this study was to investigate the effect of ecological environments on panicle traits and its relationship with subspecies characteristics in filial generations of cross between indica and japonica. 【Method】Two RILs populations, one derived from the cross between Zhongyouzhao8 (indica) and Toyonihiki (japonica) named as RIL1, the other derived from the cross between Qishanzhan (indica) and Akihikari (japonica) named as RIL2, were grown in Liaoning and Sichuan to study the effect of ecological environments on panicle traits and its relationship with subspecies characteristics. 【Result】The panicle morphological traits, anatomic traits and subspecies characteristics changed significantly. From Liaoning to Sichuan, panicle neck width and the number of large vascular bundles in panicle neck decreased, the number of small vascular bundles in the second top stem and the ratio of large vascular bundles between the second top stem and panicle neck increased, the seed setting rate and seed setting rate on secondary branch decreased significantly. Cheng’s index was more japonicalinous in Sichuan than in Liaoning. The number of large vascular bundles in panicle neck, the ratio of large to small vascular bundles in panicle neck, the ratio of large vascular bundles between the second top stem and panicle neck, seed setting rate and 1000-grain weight showed a significant difference in different subspecies types. The number of vascular bundles showed a significantly positive correlation with the panicle sink structure traits. But there was no significant correlation with the grain plumpness traits. Contrarily, subspecies characteristics showed a positive correlation with the grain plumpness traits and no significant correlation with panicle sink structure traits. 【Conclusion】The effects of ecological environments on panicle traits were significant. It is a feasible method to select and improve the vascular bundles traits based on panicle neck width. Because the mutual restraint relationship is found among the number of large vascular bundles in panicle neck, the grain plumpness traits and Cheng’s index, the breeders have to take all factors into consideration in northern China.

Key words: rice, ecological environment, cross between indica and japonica, subspecies characteristics, panicle traits, recombinant inbred lines