运用分子标记辅助选择技术改良9311白叶枯病抗性的研究

以9311为轮回亲本,以IRBB21为抗白叶枯病供体亲本,通过杂交和三次回交以及两次自交,结合农艺性状的选择,建立起具44个株系的BC3F3群体。分别用连锁标记pTA248和基因内STS标记MXA21对抗性基因Xa21进行前景选择。用均匀分布在水稻全基因组的248个SSR标记,进行两亲本之间的多态性分析,获得76个具多态性的SSR标记,用于背景选择。结果选到基因型背景回复到轮回亲本的73．68％——88．16％,且Xa21基因纯合的株系4个,分别为M071、M082、M086和M087。以Xa21的鉴别菌系菲律宾6号小种PX099接种鉴定表明,9311为感(S),IRBB21为抗(R),中选株系M071和M082的抗性与IRBB21相同,为抗(R)级,M086和：M087抗性略低于IRBB21,为抗到中抗(R／MR),这两个株系内单株之间抗性有差异。农艺性状考察结果显示,中选株系与轮回亲本9311相似。以中选株系M086与培矮64S配制的Fl和原组合两优培九(培矮64S／9311)进行比较,对白叶枯病的抗性有了明显提高,综合农艺性状相似。论文就白叶枯病抗性基因的综合利用以及育种方法进行了讨论。

Studies on Increasing Resistance of 9311 to Bacterial Blight by Molecular Marker Assisted Selection

The rice bacterial blight (BB) is one of the most serious diseases in China as well as other rice growing-area in the world. Liangyoupeijiu (Pei-ai 64/9311), apopular two-line hybrid rice, is susceptible to BB. The molecular marker-assisted selection (MAS) is an effective method to enhance the resistant level in rice breeding program. In the present study, 9311 was used as recurrent parent, and IRBB21 (Xa21) as gene donor resistant to BB. 9311 was crossed with IRBB21 followed backcrossing for three times and selfing for two times. 44 breeding lines (BC 3F 3) were selected phenotypically. The foreground selections were conducted by a linked marker, pTA248, and a co-segregated STS marker, MXA21. The results showed that 4 lines designated as M071, M082, M086 and M087 were homozygous for Xa21 gene. A Philippine Xoo (Xanthomonas oryzae pv.Oryzae) race 6, PXO99 was used for identifying the BB resistances of selected lines by artificial inoculation. The M071 and M082 were resistant to BB, with a same resistance degree as IRBB21, and the resistance of M086 and M087 were between the level of R (Resistance) and MR (Middle Resistance). 248 SSR (simple sequence repeat) primers were filtrated for the polymorphism between parents 9311 and IRBB21. 76 polymorphic SSR markers were found. The four selected lines, M071, M082, M086 and M087 with BB resistance, were analyzed by these markers for comparing genetic background with recurrent parent, 9311. The 73.68%-88.16% of genetic background in the selected lines were recovered back to the recurrent parent. The agronomic traits of the lines were similar to 9311. The BB resistance of F 1 hybrid (Peiai64S/M086) was improved and the agronomic performance was similar to the original hybrid, Liangyoupeijiu (Peiai64S/9311).