Biochemical factors associated with vegetative phase resistance against yellow stem borer, Scirpophaga incertulas (Walker) in land races of rice

A total of 50 local land races were screened against infestation of yellow stem borer, Scirpophaga incertulas (Crambidae: Lepidoptera) at vegetative phase under natural infestation (0 to 65%) during kharif 2019. Among them 18 land races were selected from each category of resistance based on standard evaluation system for rice. The estimation of biochemical constituents in rice stem (60 days old plants) of different categories was done to establish a relationship between various biochemical components with resistance/ susceptibility. Studies revealed that higher amounts of total sugars, reducing sugars and crude proteins were found in susceptible lines compared to resistant land races and were positively correlated with stem borer infestation. Total free amino acids, total phenols and tannins were found to be higher in resistant than susceptible varieties and were negatively correlated. The mineral content in the stem viz., nitrogen was positively correlated whereas phosphorous and potassium were found in higher quantities in resistant categories (2.19 – 2.37%) than susceptible ones and were found to be negatively correlated with infestation of yellow stem borer (-0.95).