籼粳交后代中的穗型指数与亚种特性及产量性状的关系

 以两个典型的籼粳交重组自交系F6群体(RILSA：中优早8号／丰锦;RILSB：七山占／秋光)为试材，分别在四川和辽宁种植，研究穗型指数（PTI）与亚种特性及产量性状的关系。结果表明，PTI在籼粳交后代中表现连续变异，籼粳交可以创造大量具不同PTI的株系，可以作为理想穗型选育的来源。生态环境对PTI有显著影响，从辽宁到四川，PTI显著变小。 PTI与大多数亚种特征性状呈显著负相关。PTI在不同亚种类型间有明显差异，总体上有籼(H)>偏籼(H′)>偏粳(K′)>粳(K)的趋势，但PTI不可以作为判别亚种类型的依据，因为籼粳交后代中的PTI在不同亚种类型间交错重叠。PTI与穗部性状和产量性状大多呈负相关，两群体中绝大多数株系的PTI为中下部优势型，在产量上具有明显优势。

Relationship of Panicle Type Index and Subspecies Characteristics, Yield Traits in Filial Generations of Cross Between indica and japonica Rice

Two RILs populations, one derived from the cross between Zhongyouzao 8(indica) and Toyonishiki(japonica) (RILSA), the other derived from the cross between Qishanzhan(indica) and Akihikari(japonica) (RILSB). were grown in Liaoning and Sichuan, China to study the panicle type index (PTI) and its relationship with subspecies characteristics and yield traits. PTI is the ratio between the number of axis internode whose number of grains in the secondary rachis branch is the most in the primary rachis branches and number of the primary rachis branches. With continuous distribution of PTI and numerous of lines with different PTIs in the progenies, indica-japonica hybridization could be the sources of ideal panicle type. PTI was significantly influenced by environments, with a significant decrease from Liaoning to Sichuan. A significantly negative correlation was found between PTI and most of subspecies characteristics. PTI significantly varied with subspecies types. As a whole, it showed a trend as follows: indica(H)> indicalinous(H') >japonicalinous(K') >japonica(K). However, it is not appropriate to regard PTI as the parameters for subspecies classification in rice because PTI was recombined in the filial generations of cross between indica and japonica. A negative correlation was found between PTI and panicle characters as well as yield traits. Based on PTI values, most of lines from the two populations were middle and lower dominant type with significant yield advantages.