Role of Oxalic Acid in Expression of Resistance against the Pod Borer Helicoverpa armigera (Lepidoptera: Noctuidae) in Chickpea Varieties

Background: Pod borer is most serious problem to cultivation of chickpea across the world. In India, Madhya Pradesh rank first in both area and production of chickpea. This region is considered most affected yield of chickpea due to H. armigera. Host plant resistance is an important component for managing this pest. To develop cultivars with resistance to insects, it is important to understand the role of oxalic acid associated with resistance to this pest. The current study aimed to study the role of oxalic acid in expression of resistance against the pod borer Helicoverpa armigera (Lepidoptera: Noctuidae) in chickpea varieties under climate change. Methods: This investigation was carried out at Research Farm of Soybean Seed Production-Unit, College of Agriculture, JNKVV (MP) during Rabi season 2019-20 and 2020-21. The field experiment was laid out in split split plot design with 24 treatments and three replications. The treatments included three date of sowing i.e. 15th November, 30th November and 15th December as a main plots, two irrigation levels i.e. I0-no irrigation and I1- irrigation at 35 DAS as a sub plots and four chickpea varieties i.e. JG 12, JG 36, JG 14 and JG 24 as sub sub plots. The observation on number of eggs and larval population of H. armigera were recorded from one-meter row length (mrl). At five randomly selected places were averaged separately for each plot and made in to number of eggs and larval population per meter row length (mrl). The amount of oxalic acid in chickpea leaves was determined by UFLC method. The correlation was worked out with population of pod borer and amount of oxalic acid in chickpea varieties.
Result: In this investigation, the ultra-fast liquid chromatography (UFLC) profiles of the leaf exudates of chickpea varieties exhibited amounts of oxalic acid significantly negative correlation with egg count and larvae incidence of H. armigera.
