Biochemical changes associated with dry root rot development in pigeonpea

Pigeonpea is one of the protein rich legume crop grown in tropical and subtropical regions of the world. It is the second most important pulse crop of India after chickpea. It is infected by many fungal diseases. Among them dry root rot caused by Rhizoctonia bataticola is an emerging disease as the most destructive constraint to pigeonpea production. Infection by pathogen brings changes in vital processes inside the plant leading to wide fluctuations in sugar content (total sugars, reducing sugars and non-reducing sugars), phenols, activity of enzymes viz. peroxidase (POD) and polyphenol oxidase (PPO) were altered. The estimation of these compounds helps in understanding the extent of host resistance to the pathogen. Interaction between a plant and a pathogen resulting in the induction of numerous host specific biochemical responses, so that the plant could withstand attack from pathogens. Maruthi (Susceptible), ICPL-15017 (Moderately resistant), GRG-811 (Resistant) genotypes were selected for determining the biochemical changes with respect to dry root rot disease development. The susceptible genotype (Maruthi) had less amount of total sugars, reducing and non-reducing sugars compared to moderately resistant genotype (ICPL-15017) and resistant genotype (GRG-811). The sugars were more in the healthy plants as compared to infected plants. Total phenols, polyphenol oxidase and peroxidase were maximum at 60DAS in inoculated soil in all the three genotypes. The amount of increase was more in the inoculated plants. The amount of phenol and enzymes were more in the resistant genotype compared to susceptible and moderately resistant genotypes.”