陇南不同区域内两个小麦品种上条锈菌群体的毒性分析

Population Virulence Analysis of Puccinia striiformis f.sp.tritici on Two Wheat Cultivars in Different Zones in Longnan

为了解陇南越夏区内小麦品种铭贤169和小偃22上条锈菌的毒性组成及遗传多样性,利用19个中国小麦条锈菌鉴别寄主对陇南4个越夏区内两个小麦品种上采集分离的236个单孢菌系进行毒性分析。结果表明,陇南越夏区小麦条锈菌群体毒性结构复杂,不同区域间毒性多样性存在显著差异。在236个菌系中,198个被鉴定为13个已知小种(致病型),其中CYR32和CYR33为优势小种,频率分别高达30.51%和29.24%;其他11个小种(致病型)主要是水源11类群和Hybirde 46类群,频率较低,不足5%。另外38个菌系是能稳定侵染贵农22的新菌系,可归为两类,分别具有CYR32和CYR33致病特点,频率分别为7.20%和8.90%。所以当前抗病育种应以CYR32和CYR33为主,兼顾水源11、Hybirde 46、V26等其他致病类群。在铭贤169上,条锈菌群体毒性Nei’s基因多样性指数和香农信息指数分别为0.20和0.33,在小偃22上分别为0.17和0.28,说明铭贤169上的条锈菌群体毒性多样性高于小偃22,这种差异可能是寄主的定向选择作用和环境条件共同作用的结果。

Stripe(yellow)rust,caused by Puccinia striiformis f.sp.tritici(Pst)is one of the most destructive wheat diseases in China.In order to explore the virulent component and population diversity of Pst on different cultivars from over-summering zones in Longnan Gansu province,236 single pustule isolates were collected from 2cultivars of four over-summering areas,using 19 Chinese differentials hosts to analysis the virulence.The results showed that population virulence structure of Pstin Longnan was complicated.Virulence diversity has significant difference among different areas.198of236 single pustule isolates were identified into 13 phenotypes,of which CYR32 and CYR33were two dominant races,the ratio was 30.51%,29.24%,respectively.Other 11 phenotypes,which ratio was less than 5%,were distinguished into Suwon 11 group and Hybirde 46 group.The other 38 new races that virulent to Guinong 22,can be classified into two groups.One group likes CYR32 and the other likes CYR33,the ratio was 7.20%,8.90%,respectively.Thus,the wheat breeding resistant to disease should object the main races CYR32 and CYR33and not ignore Suwon11,Hybirde 46 and V26in cur-rent in Longnan.The population virulence Nei's gene diversity index(H)and Shannon's information index(I)on Mingxian 169 and Xiaoyan 22 were 0.20,0.17 and 0.33,0.28,respectively,indicating that population virulence diversity in two cultivars have significant differences(α=0.05).The diversity of virulence on Mingxian 169 was richer than that on Xiaoyan 22,which can be caused by the directional selection of hosts and interaction of environment.The results of this study will provide theoretical basis to distribute the resistance genes reasonably in Longnan in future.