株型改良在水稻高产优质新品种选育中具有重要地位。以东北地区最具代表性的直立穗型品种辽粳5号和日本著名的优质米品种秋田小町(弯曲穗型)杂交构建的重组自交系(RIL)群体为试材,分析后代群体株型性状的变化规律及其相互关系。研究结果表明,RIL群体中株型性状发生了显著的分离,大多数株型性状符合多基因控制的数量性状遗传规律,在后代群体中可以重新组合,但不同株型性状间的相关性有显著的不同。植株较高的株系,穗子一般较长,颈穗弯曲度较大,叶片狭长,枝梗数少,着粒较稀,这与秋田小町的株型特点很类似;反之,植株较矮的株系,穗子一般较短,穗型较直立,叶片短宽,枝梗数较多,着粒较密,这与辽粳5号的株型特点很类似。这一现象可能与控制某些株型性状的基因存在一因多效或基因连锁有关。尽管出现概率偏低,中日水稻品种典型株型性状仍可以相互结合,育种者通过杂交后定向选择的方法,可以创造出综合二者特点(如长剑叶-短密穗型或矮秆-长穗型)的水稻新株型。

Plant type improvement plays an important role in breeding of new rice varieties with high yield and good quality. A recombinant inbred lines (RIL) population, constructed by crossing Liaojing 5, the most representative rice cultivar with erect panicle type in Northeast China with Akita Komachi, the Japanese famous good quality rice variety with curved panicle type, were used as test material to investigate the variations in plant type traits in the progeny and their mutual relationship. The results showed that there was remarkable separation in plant type traits among RIL population, most of plant type traits accorded with inheritance of quantitative traits controlled by multi genes.These plant type traits could be recombined in the progeny, but the correlation between different plant type characters significantly differed. Similar to Akita Komachi, the RILs with higher plant height always characterized by long panicle, large panicle curvature, small leaf width, few number of branches, low grain density. However, the RILs with dwarf plant height tended to have short panicle, small panicle curvature, large leaf width, large number of branches, large grain density, similar to Liaojing 5. This phenomenon was related to some genes pleiotropy or linkage which controlled some plant type traits. Despite the low probability, the typical plant type characters of Chinese rice varieties and Japanese rice varieties could be combined with each other. Breeders could create new varieties with comprehensive characteristics of plant type through hybridization and direct selection, such as long-flag-leaf and short-dense-panicle type or dwarf and long panicle type.