Effect of different meteorological parameters on germination of inoculum of teliospores of Tilletia indica in rice-wheat rotation system in Punjab, India

Abstract

Dynamics of inoculum in relation to meteorological parameters affecting occurrence of Karnal bunt epidemic in wheat in Punjab was studied during the years 2001-02 and 2002-03. There existed an intricate relationship between germination of teliospores of Tilletia indica, the causal organism of karnal bunt of wheat and meteorological parameters. The ambient and soil temperature showed negative relationship with the germination of teliospores. Increase in temperature beyond 25 oC resulted decrease in germination of teliospores. Relative humidity had significant positive relationship with germination of teliospores and maximum teliospore germination was recorded when relative humidity was more than 75 per cent. Different models were developed for prediction of disease possibility based on viability of inoculums depending on meteorological conditions. Based on humid thermal ratio, the best fit models for forecasting viability and germination of teliospore of T. indica throughout the year and during crop season were developed which explained 65 to 89 per cent and 60 to 52 percent of the variations, respectively.