水稻品种五丰占2号的白叶枯病抗性遗传分析

研究了五丰占2号的白叶枯病抗性遗传及在回交世代中的抗性表现。结果表明,用白叶枯病菌株浙173（Ⅳ型）接种，五丰占2号表现中抗，IRBB5表现抗；五丰占2号的白叶枯病抗性受微效多基因控制，基因效应分析表明，该性状符合加性-显性模型，以加性效应为主；隐性主效基因xa5控制的IRBB5对白叶枯病菌株浙173的遗传符合隐性主基因的分离比。对白叶枯病菌株浙173的抗性反应与xa5基因的PCR检测结果一致。在五丰占2号2/IRBB5 B1F1群体中，基因型Xa5Xa5与Xa5xa5的分离比为1∶1；在五丰占2号2/蜀恢162 B1F1群体中，白叶枯病抗性达到五丰占2号水平的植株数占群体总数的68.3%。如果要将IRBB5中的xa5基因与五丰占2号的微效基因聚合，用五丰占2号回交1次是必要的。

Inheritance Analysis of Resistance to Bacterial Blight in Rice Cultivar Wufengzhan 2

The inheritance of resistance to bacterial blight(BB) in Wufengzhan 2 (WFZ2) and IRBB5 and their backcross generations were analyzed. IRBB5 and WFZ2 presented resistance and moderate resistance to strain of Chinese pathotype Zhe 173,respectively. The BB resistance of WFZ2 was controlled by minor polygene. The character was conformed to additive dominant model and mainly controlled by additive effects. The resistance in IRBB5 was controlled by a recessive major gene xa5 and the progeny populations of IRBB5 and susceptible lines segregated in the ratio of one recessive major gene. The resistance reaction was consistent with PCR analysis of xa5 gene. In WFZ2 2 /IRBB5 B₁ F₁ population, the ratio of genotype Xa5Xa5 to genotype Xa5xa5 was 1∶1. In WFZ2 2 /Shuhui 162 B₁ F₁ population, 68.3% plants showed resistance like WFZ2. Gene pyramiding line with xa5 and minor polygene could be obtained by one backcross with recurrent parent WFZ2.