FIELD AND LABORATORY SCREENING OF IMPROVED GENOTYPES FOR RESISTANCE TO MAJOR INSECT PESTS IN PIGEONPEA

Abstract

Pigeonpea (Cajanus cajan L.) production is severely constrained by the pod borer complex, particularly Helicoverpa armigera, which causes substantial yield losses. This study evaluated 38 pigeonpea genotypes from the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, India, for resistance to the pod borer complex under natural field infestation and laboratory confirmation using detached-pod bioassays against H. armigera. Field screening was conducted during the Rabi 2025–26 season without insecticidal sprays; per cent pod damage (pod borer- and pod fly-damaged pods) and 100-seed weight were recorded at maturity. In parallel, detached-pod bioassays assessed pod damage rating (PDR) and larval weight gain per cent (LWG) for each genotype. Significant variation was observed among genotypes for all traits, with healthy pod percentage ranging from 30.67% (ICPL 11253) to 62.00% (ICPL 99094) and total pod damage ranging from 25.67% to 69.33%. In the bioassay, PDR ranged from 3.33 (ICPL 99102) to 6.33 (ICPL 11229), and LWG ranged from 48.77% (ICPL 94062) to 317.96% (ICPL 20135), with ICPL 94062 and ICPL 99102 showing the lowest larval weight gain. The Multi-trait Genotype–Ideotype Distance Index (MGIDI), integrating PDR and LWG, identified ICPL 99090, ICPL 90011, ICPL 17004, ICPL 17001, and ICPL 20123 as the genotypes closest to the ideotype, indicating superior combined resistance. These findings highlight substantial genetic variability for pod borer resistance among pigeonpea genotypes and identify promising resistant sources for future breeding programmes targeting pod borer complex resistance.