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中国杂交水稻的多数不育系不抗白叶枯病,携有单个的白叶枯病抗病基因的品种易于丧失抗性。本研究通过杂交、回交和自交将两个抗病基因聚合到不育系中,进行抗性改良。用育成的抗3418S(携有Xa21)为受体,CBB23(携有Xa23)为供体,通过1次杂交、1次回交和3次自交,采用足够大分离群体在分蘖前期进行接种初筛,再进行分子标记检测复筛,确认了目标基因的聚合,实现了均位于第11染色体上的Xa21和Xa23基因间交换重组,获得双基因纯合稳定的新品系R106。又用我们育成的矮败型不育系5801A进行转育,杂交一次后,向保持系(轮回亲本)定向选择,经回交3次迅速稳定,所育成的不育系及保持系对中国的7个病原型代表菌株均表现全生育期高度抗病,可能会大大延长其抗性寿命。并讨论了改良不育系抗性的研究方法、回交次数和选择世代等问题。
Most CMS lines of Chinese hybrid rice are not resistant to bacterial leaf blight, and varieties with single bacterial leaf blight resistant genes are susceptible to loss of resistance. In this study, two resistance genes were polymerized into sterile lines by crossing, backcrossing and selfing to improve their resistance. Using bred anti-3418S (carrying Xa21) as acceptor and CBB23 (carrying Xa23) as donor, screening was carried out at a pre-tillering stage using a sufficiently large segregating population by one crossing, one backcross and three self- , Followed by molecular marker detection and re-screening to confirm the polymerization of the target gene and realize the exchange and recombination between Xa21 and Xa23 genes on chromosome 11 to obtain a novel homozygous stable R106. Again with our breeding dwarf-type sterile line 5801A for breeding, hybridization once, to the maintainer (reincarnated parent) directional selection, back quickly 3 times by the stability of the sterile line and maintainer of bred to China The seven pathogenic representative strains all showed a high resistance to disease during the whole growth period, which may greatly prolong their resistance life. And discussed the research methods of improving the resistance of CMS, the number of backcrosses and the selection of generations.