聚合抗稻白叶枯病双基因三系不育系R106A的选育研究

 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。论。

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

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.