Impact of temperature, moisture and CO2 on growth of pathogen and severity of emerging dry root rot disease of chickpea in Karnatak

Abstract

Chickpea is one of the most important food legumes being cultivated in many countries in the world. Dry root rot caused by Rhizoctonia bataticola is becoming an emerging disease and considered as potential threat to chickpea productivity and production under changing climatic scenario. The pathogenecity of R. bataticola was proved and the identity of pathogen was confirmed molecularly using ITS-1 and ITS-4 primers which produced amplified product size of 500-650 bp in three studied isolates indicating that all the isolates belonged to genus R. bataticola. The maximum colony growth of pathogen and the dry root rot disease severity was recorded at 30-35ºC which is considered as optimum temperature range for growth of pathogen and development of disease. Highest severity of dry root rot and lesser plant growth parameters such as root length, shoot length and total biomass were observed at 40-60% soil moisture regimes, irrespective of type of soil. The elevated CO2 @ 550 ± 25 ppm with 2ºC rise in temperature recorded higher dry root rot well as reduced growth parameters of chickpea. The increase in the temperature lead to decreased radial growth of pathogen and dry root rot incidence and increase in the soil moisture led to increase in growth parameters in both black as well as red soils.