水稻的白葉枯病和稻瘟病是水稻的兩大主要病害，通過分子標(biāo)記輔助選擇與傳統(tǒng)的雜交、自交相結(jié)合的方法，將抗稻瘟病的Pi9(t)基因和抗白葉枯病的Xa21及Xa23基因聚合到同一株系中，經(jīng)多代大田或/和溫室接菌鑒定、室內(nèi)標(biāo)記選擇和田間農(nóng)藝性狀的篩選，獲得了4個三基因聚合且農(nóng)藝性狀優(yōu)良的株系L17～L20.用不同國家和地區(qū)的20個稻瘟病小種、中國流行的7個白葉枯病菌系C1～C7以及安徽省流行的白葉枯病菌系進(jìn)行大田或/和溫室抗病性鑒定，結(jié)果顯示，株系L17～L20對20個稻瘟病小種均表現(xiàn)出抗性，抗性水平與Pi9(t)基因的供體親本75-1-127相當(dāng)，抗譜相同；對白葉枯病的抗性和抗譜與Xa23基因相似，不論在苗期還是在成株期均抗白葉枯病.與Xa21、Xa23基因的供體親本M12和CBB23相比，成株期的抗性水平有所增強(qiáng).利用多重PCR技術(shù)，在同一PCR反應(yīng)中可同時選擇Pi9(t)和Xa21基因，提高了PCR選擇效率.
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 andXa23 were put together. Four stable lines L17–L20 which conferred 3 homozygous resistance genes and good agronomic characteristicswere 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 bacterialblight races and an Anhui epidemic BB race in the field or/and greenhouse, 4 lines expressed resistance to blast and BB. L17–L20had high resistance to all 20 blast isolates and showed similar resistant level to and same resistant spectrum as donor variety75-1-127. 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. Usingmulti-PCR, gene Pi9(t) and Xa21 can be selected at the same time so that improves the selection efficiency.