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水稻抗白叶枯病新基因Xa23抗谱广、抗性强,被定位在第11染色体上。以携带抗白叶枯病基因Xa23的抗病品系CBB23为抗源,以优良杂交稻亲本9311和1826为受体材料,采用杂交和复交,在分离群体中利用与Xa23紧密连锁的EST标记C189进行分子标记辅助选择,通过苗期分子标记检测和成株期农艺性状选择,获得160份目标基因纯合且农艺性状稳定的株系。使用鉴别菌系P6,采用人工剪叶接种法,在苗期和孕穗期对21份重点株系进行了抗性鉴定,所有株系在苗期和孕穗期都表现抗病。同时对3个不育系与其中5个株系配制的15个杂交组合进行了抗性鉴定,所有组合在苗期表现抗或中抗,在孕穗期表现抗。对其中6个杂交组合进行了品比试验,2个组合产量略低于对照两优培九,其余4个组合的产量均高于两优培九,用于测配的3个株系C6201、C6271和C6351有望作为杂交稻恢复系在生产中应用。研究表明在育种进程中利用与Xa23基因紧密连锁的分子标记C189开展抗白叶枯病分子标记辅助育种是一种有效的途径。
Xa23, a new gene for resistance to bacterial leaf blight in rice, has broad spectrum of resistance and is localized on chromosome 11. Using the resistant strain CBB23 carrying XA23 and the elite hybrid rice 9311 and 1826 as the recipient materials, hybrids and reciprocal hybrids were used in the segregating population, respectively, using the C189 EST marker C189 closely linked to Xa23 Through molecular marker-assisted selection and molecular marker selection at seedling stage and agronomic traits selection at adult stage, 160 lines with homozygous target genes and stable agronomic traits were obtained. The identification of the strain P6, the use of artificial leaf pruning inoculation, seedling and booting stage of the 21 key strains were identified, all strains showed resistance at seedling and booting stages. The resistance of 15 hybrid combinations were tested in three CMS lines and five of them. All the combinations showed resistance or resistance in seedling stage and resistance in booting stage. The yield of two combinations was lower than that of Liangyoupeijiu and the yield of the other four combinations was higher than that of Liangyoupeijiu. The three lines C6201, C6271 and C6351 for mating test were expected to hybridize Rice restorer lines are used in production. Studies have shown that it is an effective way to carry out molecular marker-assisted breeding against bacterial leaf blight using molecular marker C189 closely linked to Xa23 gene during the breeding process.