水稻广亲和系的选育

水稻广亲和基因的发现及其遗传研究 ,揭开了籼粳稻亚种间杂种一代半不育现象的遗传本质 ,为利用水稻亚种间杂种优势指明了方向。但是 ,已知的广亲和材料 ,绝大多数为古老的农家品种 ,农艺性状不良 ,如植株太高 ,株叶形披散和生育期很长等 ;不能直接作为选配优良组合的亲本加以利用。因此 ,培育具有优良农艺性状和经济性状、可供实用的水稻广亲和系就显得非常重要 ,这是开展亚种间杂种优势育种的首要任务之一。普通栽培稻有籼稻、粳稻和爪哇稻三个亚种 ,所以亚种间的杂交可分为籼粳交、籼爪交和粳爪交三种形式。初步研究表明 ,水稻杂种优势强弱的程度 ,具有籼粳交 >籼爪交 >粳爪交 >籼籼交 >粳粳交的一般趋势。也就是说 ,亚种间的杂种优势一般要强于品种间的。为了能充分利用各种形式的亚种间杂种优势 ,提高育成强优组合的几率 ,就有必要建立籼、粳、爪三个亚种类型的优良广亲和系。我们在以前工作的基础上 ,近年来开展了水稻广亲和系选育的研究 ,已取得一些进展和结果 ,育成了粳型广亲和系培C3 11,爪哇型广亲和系轮回 4 2 2 ,籼型广亲和系培矮 64以及广亲和光敏核不育系培矮 64S。

Breeding for Wide Compatibility Rice Lines

The genetic basis has been revealed of the phemomenon of semi sterility in F 1s of indica/japonica crosses, after the discovery of and genetic studies on the wide compatibility gene (WCG) in rice. Therefore, the direction has been pointed out, which intersubspecific heterosis should be exploited. But most of the existing WCG materials, unfortunately, belong to troditional domestic varieties with such undesirable characters as poor plant type, over tallness, long and droopy leaves and inapprepriate growth duration. So they cannot be used directly in hybrid rice breeding program as parents. It is very important to develop practical WCG lines which are of elite agronomic and economic characters for indica/japonica hybrid rice breeding. Cultivated rices are divided into three subspecies, namely, indica, japonica and javanica. Crosses of intersubspecies involve indica/japonica, indica/javanica and japonica/javanica. Preliminary studies indicated that the magnitued of heterosis in rice can be generally differentiated in consecutive order of indica/japonica, indica/javanica, japonica/javanica, indica/indica and japonica/japonica. In other words, heterosis of intersubspecific crosses is higher than that of intervarietal crosses. To utilize all kinds of heterosis of crosses of intersubspecies and to increase opportunities of success in selection, it is necessary to set up elite WCG lines of indica, japonica and javanica type. Based on this knowledge and our previous work, studies of breeding for WCG rice lines have been conducted in recent years and progress has also been made. An array of WCG lines are successfully developed like PC311 (japonica), Lunhui 422 (javanica). Paii 64 (indica) and Paii 64S (thermo and photoperiod sensitive genic sterility).