中国小麦条锈菌4个主要流行小种的寄生适合度

Parasitic fitness of four major prevalent races of Puccinia striiformis f. sp. tritici in China

以12个全国大面积种植的小麦生产品种和1个高感品种为试材,利用抗性组分法研究了中国小麦条锈菌(Puccinia striiformis f.sp.tritici,Pst)4个主要流行小种条中32号、条中31号、水源11-14和水源11-4的寄生适合度。因子分析结果表明,病害量是度量条锈菌生理小种寄生适合度最重要的参数,其次是夏孢子生活力、产孢能力、产孢面积、产孢期,由此提出寄生适合度=(产孢量×侵染概率×夏孢子堆密度×夏孢子萌发率)/潜育期。研究还发现,条中32号的寄生适合度最高,致病性最强,与目前该小种为优势小种的事实相符;水源11-14的寄生适合度较高,有较大的发展潜力,在抗病育种中应予以高度重视。

The capacity infection and development on host of pathogenic fungi is most likely determined by the relative parasitic fitness of host-pathogen interactions. Twelve important wheat cultivars were used as the testing materials to determine the principal parasitic fitness of four prevalent races of wheat stripe rust （Puccinia striiformis f. sp. tritici, Pst） in China, namely CYR32 （Chinese yellow rust）, CYR31, SUll-14 and SU11-4. A total of fifteen parameters in the disease process was tested and statistically analyzed by the factor analysis. The results indicated that disease capacity was the most important component of parasitic fitness, when urediniospore vitality, sporulating intensity, sporulating area and period were secondly important, leading to conclude that the relative parasitic fitness of the pathogen could be determined by spore yield x infection probability x uredium density x percentage of urediniospore germination/latent period. CYR32 displayed the higest relative parasitic fitness and virulence in all of four races tested, which was the reason why it became the most predominant race at present. Comparing with CYR31 and SU114, SUll-14 possessed of higher parasitic fitness on 12 wheat cultivars tested. It suggested that SUll-14 would become a predominant race in the near future, and should be paid more attention to monitor its virulence evolution and dynamics.