杂交水稻叶瘟抗性杂种优势的遗传分析

 本文用水稻7个不育系、7个恢复系及其按NCⅡ设计配制的49个杂交组合,在4个指标上研究了杂交水稻叶瘟抗性的杂种优势和遗传。结果表明:杂交水稻的叶瘟抗性不仅具有较强的杂种优势,而且在组合间变异很大;叶瘟抗性遗传力高,其受加性和非加性遗传共同控制,但加性遗传明显较为重要,源于恢复系的加性效应明显相对重要于不育系的加性效应;亲本叶瘟抗性与其一般配合力效应呈显著或极显著正相关;缙恢1号具有较好的一般配合力效应和较大的特殊配合力方差,可作为优良抗病亲本加以利用,K42A、K40A、多恢1号、成恢149具有较好的一般配合力效应和较小的特殊配合力方差,在抗稻瘟育种中具有较大利用价值。讨论认为:在抗叶瘟育种中,对亲本的抗性评鉴和选育抗病亲本尤其是恢复系至关重要,但不能以此忽略对杂交组合的抗性评鉴。

GENETIC ANALYSIS FORHETEROSIS OF RESISTANCE TO LEAF BLAST IN HYBRID RICE

Heterosis and genetic analysis of resistance to leaf blast in hybrid rice were studied by four resistance indices with seven CMS lines, seven restorers and 7×7 incomplete diallel crosses.The results indicated that the resistance of hybrid rice to leaf blast had a stronger he terosis and a considerable variation among the crosses. The resistance was controlled by additive and non additive heredity components.The former was more important relatively than the later and its heritability was high.The additive heredity component of the restorers was more important than that of the CMS lines.The resistance of each parent was significantly or extremely significantly positive related to its general combining ability (GCA).Having better GCA and bigger variance of special combining ability(SCA)of the resistance than other tested parents had, Jinhui No.1 could be utilized as excellent parent in the resistance breeding. Having better GCA and smaller variance of SCA of the resistance than other tested parents had, K42A, K40A, Duohui No.1 and Chenghui 149 had fair application value in the resistance breeding.