Epidemiology and Identification of Sources of Resistance against Yellow Rust of Wheat in Kashmir
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Date
2023
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SKUAST Kashmir
Abstract
Stripe rust, caused by Puccinia striiformis f.sp. tritici, is a potential threat to wheat crop productivity among all the rust diseases. It is a devastating wheat disease that occurs throughout the growing season in wheat areas with cool and moist weather conditions. The present study was conducted on set of fifty-one (51) wheat germplasm lines for screening against yellow rust and to assess the influence of weather parameters like temperature, precipitation, relative humidity and windspeed on yellow rust development. The experimental material included three yellow rust susceptible checks viz., PBW752, PBW343 and HD2733. The wheat germplasm lines were evaluated during Rabi, 2020-2021 and 2021-2022 under augmented block design. The artificial disease epidemic was created in the field following repeated sprays of yellow rust inoculum till appearance of maximum susceptibility on susceptible checks. The germplasm lines were scored following modified Cobb scale. Parameters used as criteria to identify slow rusting included final rust severity (FRS), area under disease progress curve (AUDPC), coefficient of infection (CI) and apparent infection rate (r-value). Among these parameters, FRS, CI and AUDPC were found to be reliable to assess slow rusting in the genotypes whereas apparent infection rate appeared to give unreliable estimations of slow rusting in the current study. The results further revealed that genotypes IC111672, IC111687, IC111691, IC111703, IC111921, IC111939, IC128416, IC128685 and IC111787 had low disease severities (<30%), lower AUDPC values (<30% of the highly susceptible cultivar) and CI values (<20) and as such there rate of disease progress was slow. During both the cropping seasons eight genotypes viz., IC111672, IC111687, IC111691, IC111703, IC111921, IC111939, IC128416 and IC128685 were resistant, one genotype IC111787 was moderately resistant, twenty-seven genotypes, PBW752, IC104538, IC111738, IC111867, PBW343, IC111959, IC11252, IC118721, IC128168, IC128187, HD2733, IC128512, IC128620, IC128640, IC128650, IC111947, IC128409, IC128411, IC128438, IC128654, IC111822, IC111839, IC111914, IC111693, IC111879, IC111968 and IC11177 were moderately susceptible, eight genotypes, IC111717, IC111723, IC111745, IC113725, IC116276, IC128339, IC128666 and ICI38379 were susceptible and 7 genotypes IC113737, IC118722, IC128177, IC128211, IC128215, IC128283 and IC128388 were found highly susceptible to yellow rust. Correlation coefficients indicated that maximum and minimum temperature, morning and evening relative humidity, rainfall and wind speed showed significant relationship with yellow rust severity. Significant R2 value was observed when weather parameters were involved to develop a regression model for stripe rust forewarning. Ninety-eight per cent variability in disease severity due to weather parameters, i.e., maximum and minimum temperature, morning and evening relative humidity, rainfall and wind speed was indicated by R2 value. Slow rusting genotypes, IC111672, IC111687, IC111691, IC111703, IC111921, IC111939, IC128416, IC128685 and IC111787 identified from the study could further be tested for their genetic investigations and their suitability for deployment over space and time. Regression equation can be used for forewarning of disease severity and can be used for timely and effective management of disease so as to reduce the yield losses caused by this particular disease.
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Keywords
Puccinia striiformis f.sp. tritici, Slow rusting, Weather parameters, Wheat, Yellow rust, Plant Pathology.