兼抗白叶枯病和细条病水稻材料的创新及育种利用

Innovation and application of breeding utilization for resistance to bacterial blight and bacterial leaf streak

【目的】探讨抗白叶枯病兼抗细条病基因在杂交稻抗性改良利用中的可行性,为丰富我国水稻育种遗传基础提供参考依据。【方法】利用分子标记方法对102份水稻品种资源(材料)进行抗白叶枯病兼抗细条病xa5基因筛选。以携带xa5基因且对白叶枯病和细条病具有良好兼抗性的亲本为抗源,与感病栽培稻杂交,通过系谱法,结合分子标记辅助选择,培育优良杂交稻恢复系。优良恢复系与不育系组配出强优势组合,分析强优势组合的抗性和综合农艺性状。【结果】从102份水稻品种资源(材料)中筛选出兼抗白叶枯病和细条病xa5基因的稻种资源17份,经抗性鉴定,DP3、IRBB5、N36、N776、N777、N779和P89对白叶枯病和细条病均表现较好的兼抗性。以广恢998为母本、以DP3与9311的杂交后代优良单株Y240-1为父本进行杂交,结合分子标记辅助选择,经多代自交选育,培育出含xa5基因的优良恢复系野香占。以野香占为父本、不育系平丰A为母本组配出强优势杂交组合平丰优香占。该组合对白叶枯病和细条病均表现为中抗,同时中抗稻瘟病,米质达到部标2级优质米标准。【结论】抗水稻白叶枯病兼抗细条病的xa5基因具有部分显性效应,可用于杂交水稻育种改良;培育出含有野生稻血缘的野香占能组配出中抗白叶枯病和细条病强优势水稻杂交组合,有助于丰富和拓宽水稻育种遗传基础。

【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 2 nd 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.