|
Variation of population composition of the wheat rust caused the lose of leaf rust resistance in wheat cultivars,and make the rust pandemic. Therefore, Identification of race (pathotypes) and system monitoring, ascertain the types and the composition and pathogenic characteristics of the physiological races. It is the basis of breeding new resistant cultivars and deploying resistant wheat cultivars. Survey of the pathotypes and the frequency of virulence genes in China play an important role in agricultural production.Seven hundred and fourty-one collections of Puccinia triticina Eriks. were obtained from rust-infected leaves throughout HeBei, Henan and Shandong provinces of China in 2008. Six hundred and seventy-seven single-uredinial isolates collected were tested for pathogenicity using 40 lines with different leaf rust resistance genes.Two hundred and seven virulence phenotypes of P. triticina were detected, and among which PHTT was the most predominant one consisting of 10.04% of the population. THTT (8.12%), THJT (4.73%), PHST (3.55%), THKT (3.24%), PHRT (3.10%), THSS (2.36%), THRT (2.22%), THTS (2.07%) and PHKT(2.07%), also occurred at a relatively high frequency. The part of the same main phathotypes and the difference main phathotypes were found in the various provinces of China. The results also showed that the virulence frequency of V1, V2b, V2c, V3, V3bg, V10, V11, V14a, V14b, V16, V25, V26, VB, V33, V33+34 and V37 were above 60% in 3 provinces. Lower than 30% isolates in the population were virulent to Lr9, Lr19, Lr24, Lr38, Lr39, Lr42, Lr21+39 and Lr47(Pavon7S3), respectively, suggesting that these genes be applicable in wheat breeding for resistance. The virulence frequency of V2a and V29 were 30%-60% among 3 provinces, and the corresponding resistance genes can be used in gene deployment and pyramiding of several resistance genes. Frequency of a few virulence genes was different among different provinces. V47 were not detected in the seedling stage test. Isolates from HeBei were avirulent to Lr47(Pavon7S3) in adult stage corrsponding croping season.Apart from a few virulence genes and main pathotypes, the frequency of other virulence genes and other main virulence phenotypes were nearly the same among different ecological zones of HeBei. Thirty wheat cultivars of HeBei have been inoculated respectively with 15 main virulence phenotypes of HeBei, two isolates of every main virulence phenotype. The result shows obviously that the wheat cultivars are susceptible to the test pathotypes.
|