聚合抗稻白叶枯病双基因三系不育系R106A的选育研究

Pyramiding Two Bacterial Blight Resistance Genes into a CMS Line R106A in Rice

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 of the male sterile lines have no resistance to bacterial blight （BB） and the cultivars with a single BB resistance gene will break-down easily. Two resistance genes, Xa21 and Xa23 were pyramided into a male sterile line through crossing, backcrossing and selfing to improve its resistance. The PGMS line 3418S （carrying Xa21） was crossed with CBB23 （carrying Xa23）. The F1 was backcrossed with 3418S to get BC1F1, then, selfing for 3 times to pyramid the two genes and bred a new line R106 with homozygous resistance by inoculation and MAS. The new line R106 was also as a recipient for developing a cytoplasmic genetic male sterility （CMS） line R106A by the back-crossing procedure, The line R106A was highly resistant to 7 Chinese pathotypes of Xanthomonas oryzae pv. oryzae （Xoo） and showing overall resistance, which might maintain durability. The methods including backcrossing times, selecting generation were also discussed.