兼抗白叶枯病和细条病水稻材料的创新及育种利用.

【Objective】The present paper aimed to illustrate the potential utilization of the gene of resistance to bacterial blight and bacterial leaf streak, so as to provide reference for enriching genetic base of rice breeding.【Method】A total of 102 rice cultivars were used to screen by molecular marker for the gene xa5, which mediated the resistance for both for resistance to bacterial blight and bacterial leaf streak. The parents carrying xa5 gene and having good resistance to bacterial blight and bacterial leaf streak were used as resistant sources to cross with susceptible cultivated rice. Through pedigree method and molecular marker-assisted selection（MAS）, elite hybrid rice restorer lines were cultivated. The excellent restorer lines and sterile lines were combined with strong heterosis combinations to analyze the resistance and comprehensive agronomic traits of strong heterosis combinations.【Result】A total of 17 cultivars were screened, which carried xa5 gene from 102 rice germplasm resources（materials）. Among these cultivars, DP3, IRBB5, N36, N776, N777, N779 and P89 were well resistant to both bacterial blight and bacterial leaf streak. An elite line Y240-1 was selected from the cross between DP3 and 9311. Moreover, 998 R was crossed with elite individual Y240-1. With molecular MAS, an elite restorer line Yexiangzhan with xa5 was developed from the cross of 998 R and Y240-1, after multiple generations of selfing. Yexiangzhan was combined with sterile line Pingfeng A to produce an elite hybrid cultivar Pingfengyouxiangzhan, which showed higher resistance to bacterial blight and bacterial leaf streak in comparison with Pingfeng A. Pingfengyouxiangzhan was resistant to rice blast at moderate level and meet the 2nd class standard of fine quality issued by Ministry of Agriculture of China.【Conclusion】xa5 gene with resistance to bacterial blight and bacterial leaf streak of rice has partial dominant effect, which can be used for breeding improvement of hybrid rice; It is helpful to enrich and broaden the genetic basis of rice breeding by cultivating the superior hybrid combinations of rice with moderate resistance to bacterial blight and stripe disease with wild rice blood. [ABSTRACT FROM AUTHOR]