分子标记辅助培育水稻抗白叶枯病和稻瘟病三基因聚合系

水稻的白叶枯病和稻瘟病是水稻的两大主要病害, 通过分子标记辅助选择与传统的杂交、自交相结合的方法, 将抗稻瘟病的Pi9(t)基因和抗白叶枯病的Xa21及Xa23基因聚合到同一株系中, 经多代大田或/和温室接菌鉴定、室内标记选择和田间农艺性状的筛选, 获得了4个三基因聚合且农艺性状优良的株系L17~L20。用不同国家和地区的20个稻瘟病小种、中国流行的7个白叶枯病菌系C1~C7以及安徽省流行的白叶枯病菌系进行大田或/和温室抗病性鉴定, 结果显示, 株系L17~L20对20个稻瘟病小种均表现出抗性, 抗性水平与Pi9(t)基因的供体亲本75-1-127相当, 抗谱相同; 对白叶枯病的抗性和抗谱与Xa23基因相似, 不论在苗期还是在成株期均抗白叶枯病。与Xa21、Xa23基因的供体亲本M12和CBB23相比, 成株期的抗性水平有所增强。利用多重PCR技术, 在同一PCR反应中可同时选择Pi9(t)和Xa21基因, 提高了PCR选择效率。

Developing Rice Lines Resistant to Bacterial Blight and Blast with Molecular Marker-Assisted Selection

The bacterial blight (BB) and blast are two major diseases of rice. Through Molecular Marker-assisted Selection (MAS) and traditional breeding methods, hybridization and selfcross, blast resistance gene Pi9(t), BB resistant genes Xa21 and Xa23 were put together. Four stable lines L17–L20 which conferred 3 homozygous resistance genes and good agronomic characteristics were obtained through consecutive inoculation in the field or/and greenhouse, MAS and selection from agricultural aspects. By artificial inoculation of 20 blast isolates which came from different countries and areas, 7 Chinese epidemic bacterial blight races and an Anhui epidemic BB race in the field or/and greenhouse, 4 lines expressed resistance to blast and BB. L17–L20 had high resistance to all 20 blast isolates and showed similar resistant level to and same resistant spectrum as donor variety 75-1-127. At the same time, lines L17–L20 had similar resistance and spectrum to Xa23 gene both in seedling and heading stages. In the adult stage, the lines had better BB resistance than donor parents M12 with Xa21 gene and CBB23 with Xa23 gene. Using multi-PCR, gene Pi9(t) and Xa21 can be selected at the same time so that improves the selection efficiency.