水稻抗纹枯病导入系的构建及抗病位点的初步定位

Development of Introgression Lines and Identification of QTLs for Resistance to Sheath Blight

以我国目前生产中广泛应用的杂交稻恢复系蜀恢527和明恢86为轮回亲本,以江西丝苗为供体亲本配制BC2F2混合群体。通过逐代人工接种筛选,获得49个BC2F4抗病导入系。对抗病选择导入系进行基因型分析,利用基于遗传搭车原理的卡方检验对等位基因导入频率的偏离进行检测,共检测到12个显著位点,2个群体定位的QTL各有1个在以往不同群体中也能被检测到。主要农艺性状分析表明,非接种条件下,选择导入系群体的抽穗期、株高和千粒重等与轮回亲本无显著差异;在接种的条件下,在2个试验地点中,分别有6个和2个蜀恢527和明恢86背景的株系抗病性显著高于轮回亲本,产量与轮回亲本无显著差异。上述结果为水稻抗纹枯病分子育种提供了有用的信息和中间材料。

In this study,two random BC2F2 populations were developed by cross and backcross,in which two major hybrid restorer lines Shuhui 527 and Minghui 86 were used as recurrent parents respectively,and Jiangxisimiao used as donor.The bulks of the BC2F2 populations were inoculated with Rhizoctonia solani to screen the lines resistant to sheath blight,and 49 resistant introgression lines（ILs） were selected.The genotypes of ILs were analyzed with evenly distributed polymorphic SSR markers,and a total of 12 significant loci were identified by χ^2 test analysis.Among them,two allelic frequency-deviation loci were located in the same or near regions identified in the previous studies.In the field test without artificial inoculation,there was no significant difference between all the agronomic traits investigated in the selected ILs and their recurrent parents.Under heavily diseased conditions,six ILs with Shuhui 527 background and two ILs with Minghui 86 background showed similar agronomic traits and significantly higher resistance to sheath blight than their recurrent parents at two experimental sites,which can be served as immediate sources of sheath blight resistance for hybrid rice breeding and directly used in hybrid rice production.