Assessment of Genetic Divergence for Resistance to Pod Borer (Helicoverpa armigera) in Pigeonpea (Cajanus cajan L. Millsp.) Germplasm

Abstract

Pod borer (Helicoverpa armigera) is one of the most destructive pests affecting pigeonpea (Cajanus cajan L. Millsp.), causing significant yield losses and limiting productivity in pulse-based cropping systems. This study assesses the genetic divergence among pigeonpea germplasm for resistance to pod borer to identify promising genotypes for breeding programs. Field evaluations were conducted using diverse germplasm lines under natural infestation conditions to measure resistance-related traits and yield performance. Key parameters assessed included larval population density, pod damage percentage, seed damage, plant morphological traits, and grain yield. Results revealed substantial genetic variability among the evaluated germplasm, with certain genotypes exhibiting lower levels of pod and seed damage, indicating higher resistance to pod borer infestation. Resistant lines also demonstrated favorable agronomic traits, including stable yield under pest pressure. Multivariate analysis indicated clear genetic divergence among genotypes, suggesting the availability of diverse genetic resources for breeding programs. The study highlights the importance of integrating host plant resistance into pest management strategies to reduce reliance on chemical pesticides. While analytical tools were used to evaluate genetic relationships and resistance traits, the primary focus remains on crop improvement and sustainable pest management. These findings provide practical insights for breeders and farmers to select resistant pigeonpea varieties, enhance productivity, and support environmentally sustainable pulse production systems through improved genetic resource utilization.