Identifying environmental factors impacting yellow mosaic virus disease of green gram (Vigna radiata L.) Wilczek

Abstract

The relationship between environmental factors and the incidence of yellow mosaic virus disease in green gram was studied for the period of 23 years using historical data on disease index (DI) and environmental factors from 1985 to 2007. The environmental factors showed consistently significant correlations with DI during the 29th–33rd standard meteorological week (SMW) periods and the same period was taken for further analysis. Among the environmental factors, maximum temperature was highly positively correlated (r = 0.63), followed by sunshine hours in SMW 29 (r = 0.48), with the disease. However, rainfall during SMW 30–33 (r = −0.38) and evening relative humidity during SMW 29–33 (r = −0.42) were negatively correlated with disease. As these four environmental factors contribute mainly to disease, same were used to develop the functional models by conducting multiple regression analysis for the period SMW 29–33. Among these, linear model gave highest R² value (0.47) and this model was validated for the periods 2008–2010 and the predicted estimates were in full agreement with the observed estimates (R² = 0.874).

Keywords:

• epidemic window
• disease index
• yellow mosaic virus
• environmental factors
• standard meteorological weeks