Correlation coefficient between early blight severity, infection rates and meteorological factors in potato under different fungicidal spray

Correlation coefficient for early blight severity and meteorological factors in potato

Abstract

Early blight caused by Alternaria solani is a severe constraint in potato production. The severity of this disease has been increasing day by day for last few years in India due to changes in environment. The study showed that minimum temperature and rainfall revealed negative but non-significant correlation in all treatments except untreated control (T₁₀₎ in year 2012-13 whereas, maximum relative humidity showed non-significant negative correlation in all treatments except untreated control (T₁₀). Correlation between sun shine hours found positive but non-significant in all treatments except untreated control (T₁₀) in the year 2012-13. During 2013-14, maximum, minimum temperature, rainfall and sun shine hours showed non-significant positive correlation in all treatments and non-significant negative correlation found in untreated control plots (T₁₀). Maximum disease severity and AUDPC was recorded in untreated plot. The early blight disease had significant negative correlation with maximum relative humidity during 2012-13 and in year 2013-14 minimum temperature was significantly correlated. Mean infection rates showed positive but non-significant correlation with maximum and minimum temperature. The severity of early blight showed positive but non-significant correlation with maximum temperatures and sunshine hours in 2012-13 in all treatments while, it showed significant positive correlation with maximum temperature and highly significant positive correlations with sun shine hours in year 2013-14 in all treatments.