EFFECT OF WEATHER PARAMETERS ON THE DEVELOPMENT OF LATE AND EARLY BLIGHT OF POTATO
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Date
2020-09-03
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Division of Plant Pathology Sher-e-Kashmir University of Agricultural Sciences & Technology of Jammu Main Campus, Chatha, Jammu
Abstract
Potato (Solanum tuberosum L.) is one of the most widely cultivated crop which serve as a staple food in many parts of the world. Potato crop is attacked by many biotic and abiotic factors, among them late and early blight are major diseases that occurr worldwide causing significant reduction in yield. Epidemiological studies were conducted during rabi season of 2019-20 to study the late and early blight of potatodisease progression in relation to abiotic factors viz., maximum temperature, minimum temperature, maximum relative humidity, minimum relative humidity and rainfall under different dates of sowing. The study was conducted by using three defferent potato varieties viz., Kufri Badshah, Kufri Lavkar and Kufri Surya at two different date of sowing (21.10.2019 and 05.11.2019). In late blight of potato (Phytophthora infestans) disease was observed at 50th SMW in all three varieties as well as both date of sowing. During 52nd to 1st SMW, maximum disease progress from 3.6 to 6.5; 4.2 to 7.8 per cent in Kufri Badshah, 10.8 to 21.8; 12.29 to 25.39 per cent in Kufri Lavkar and 9.85 to 19.92; 11.73 to 24 per cent in Kufri Surya, in both date of sowing, respectively, with maximum and minimum temperature 15.57 and 6.840C, maximum and minimum relative humidity 92.71 and 66.29% and rainfall 24 mm. Correlation analysis revealed that maximum temperature has significant and positive correlation with severity, whereas minimum temperature and minimum relative humidity have significant and negative correlation with severity in all three varieties at both date of sowing. Multiple linear regression model showed that among all abiotic factors, maximum temperature (X1), minimum temperature (X2), maximum relative humidity (X3) and rainfall (X5) were responsible for 94.21 and 97.40; 97.33 and 97.32; 96.77 and 96.91 per cent variation in the severity of late blight of potato under first and second date of sowing in Kufri Badshah, Kufri Lavkar and Kufri Surya, respectively.
Early blight caused by Alternaria solani appeared at 51st SMW in all the selected varieties and at both date of sowing. Disease progress sharply during 1st to 2nd SMW from 2.50 to 4.06; 2.10 to 3.20 per cent in Kufri Badshah, 6.70 to 14.50; 5.40 to 11.02 percent in Kufri Lavkar and 5.10 to 10.30; 4.20 to 8.10 per cent in Kufri Surya under first and second date of sowing, respectively, with prevalence of maximum and minimum temperature 16.17 and 7.870C, maximum and minimum relative humidity 92.71% and 70.43% and rainfall 39.40 mm. Correlation analysis showed that maximum temperature has significant and positive correlation with severity, whereas, minimum relative humidity was significant and negative correlation with severity in all three varieties at both date of sowing. Multiple linear regression equations revealed that maximum temperature cause 75.89 and 75.46 in Kufri Badshah, 78.27 and 77.24 in Kufri Lavkar, 77.02 and 76.29 per cent in Kufri Surya at first and second date of sowing, respectively variation in observed severity of early blight.