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20171
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Subject: Plant Pathology × Author: Harmandeep Kaur × End date: 2017 ×
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    Virulence spectrum of puccinia striiformis f. Sp. Tritici in Punjab
    (Punjab Agricultural University, Ludhiana, 2017) Harmandeep Kaur; Jaspal Kaur
    Stripe rust of wheat, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most devastating disease of wheat worldwide. The purpose of this research was to survey Punjab fields to determine the prevalence of stripe rust, characterize the race structure of Pst on the basis of virulence and to know the molecular diversity of the pathogen population. During the year 2014-2015 disease severity was in the range of 5-60 per cent in Rupnagar while 10-20 per cent in other areas. During the crop season 2015-16 maximum disease severity was in the month of December i.e.10-40 per cent in Rupnagar followed by traces to 40 per cent in SBS Nagar and 20 per cent in Hoshiarpur, Gurdaspur, Fatehgarh Sahib and 10 per cent in Ludhiana, Patiala on different cultivars. Race characterization was done by inoculating differential lines carrying known resistance genes along with 15 supplemental cultivars with 12 Pst isolates collected from hot spot areas of Punjab along with pathotypes 78S84, 46S119 and 110S119 obtained from IIWBR, Regional station, Flowerdale, Shimla. On the basis of their reaction on differentials, 3 races namely 46S119, 110S119 and 238S119 were identified. Genes Yr1, Yr5, Yr10 conditioned resistance against all isolates tested on differentials and all isolates were virulent on Yr2, Yr3, Yr4, Yr6, Yr7, Yr8, Yr9. Variation for virulence was observed among isolates on YrSD, YrSU and Yr9+. Out of fifteen (15) supplement genotypes, six (6) genotypes namely PBW729 (Yr15), PBW730 (Yr10), BWL2763 (Yr15), BWL3277 (Yr5), BWL3558 (Yr5), BWL4405 (Yr10) having resistance genes Yr5, Yr10, Yr15 were recorded highly resistant. PBW 343 showed ‘highly susceptible’ reaction against all isolates of Pst with maximum disease severity of 80 per cent and minimum incubation period of 8-9 days. Molecular diversity (based on SSR polymorphism) showed that isolates collected from Punjab were more diverse than isolates obtained from IIWBR, Regional station, Flowerdale, Shimla. On the basis of SSR primers (SOB, PAU, Ludhiana) result revealed that previous year isolates were genetically different than current isolates.