杂交稻恢复系白叶枯病(Xathonas campestris pv.oryzae)抗性改良研究

利用携有白叶枯病抗性基因 Xa-5,Xa-7的抗源 DV_(85)衍生而来、但经济性状明显改善的 TD-1、TD-2为抗病供体亲本,与对白叶枯病感染的杂交稻优良恢复系明恢63杂交,在对目标性状——抗白叶枯病持性的强烈选择压下,与轮回亲本回交2次。然后自交,以便于其它有利基因重组,通过按产量与抗性进行鉴定与选择,目前所选育的抗18、抗21、抗25用白叶枯病强菌株浙173接种为高抗(HR),且抗病性状在与感病不育系配组的杂种 F_1中呈完全显性表达。这此抗系与珍汕97A 杂交的 F_1杂种农艺性状都近似于汕优63——珍汕97A/明恢63,在江、皖、豫、鄂等白叶枯病病区的杂交稻生产上有应用前景。再继续回交1～2次,可望获得进行白叶枯病抗性研究的近等基因系遗材料。

STUDY ON THE IMPROVEMENT OF RESISTANCE TO BACTERIAL BLIGHT(XATHOMONAS CAMPESTRIS PV.ORYZAE)IN HYBRID RICE RESTORER LINE

Rcsistant donor parent TD-1,TD-2 derived from DV_(85) with resistant genes Xa-5.Xa-7were crossed with Minghui 63,a superior hybrid rice restorer line but susceptible to bacterial blight disease.The hybrids were strictly selected for the obiective trait,resistance to bacterial blight,back-crossedsuccessively two times with recurrent parent and selfed so as to get recombination of desirable genes.Three lines Kang18,Kang21 and Kang25 were developed These lines showed highly resistant (HR)while tested by inoculation with stongly virulent strain Zhe173.Moreover,the hybrids(F_1) between theselines and susceptible male sterile lines showed complete dominance in resistance.The agricultural characters of F_1 hybrids between these resistant lines and Zhenshan 97A approximateto those of Shanyu 63 (Zhenshan 97 A/Minghu 63).These resistant lines may show promising propects forhybrid rice production in those discase prevailing areas instead of Shanyu 63.On the other hand,nearisogcnic lines may be deveioped from them for studying the resistance to bacterial blight disease.