Identification of potential resistant genotypes against defoliators in soybean

Abstract

Investigation was carried out at the All India Co-ordinated Research Project (AICRP) on Soybean, Main Agricultural Research Station, University of Agricultural Sciences, Dharwad during kharif 2023. Among 22 soybean genotypes screened for the resistance against defoliators including Spodoptera litura (Fab.), Thysanoplusia orichalcea (Fab.) and Spilarctia obliqua (Walk.) the genotype SL 1311 was found to be a superior over rest of genotypes with least per cent defoliation (12.07) and categorized as highly resistant. It was followed by genotypes VLS 108 and AMS 2021-3 with comparatively least per cent defoliation (16.52 and 16.80%, respectively) and was classified as resistant. Moderately resistant genotypes included Himso 1696, DSb 40, NRC 258 and AS 34. Genotypes KDS 1203, NRCSL 5, MACS 1756, JS 24-34, MAUS 824, KDS 1188 and Pusa Nipani 433 were categorized as least resistant. Genotypes NRC 257, RSC 1172, MAUS 814 and DSb 39 were susceptible. Furthermore, the genotypes NRC 259, NRC 260, AMS 2021-4 and JS 335 showed the most severe levels of defoliation (33.03, 32.42, 32.41 and 34.41%, respectively) and categorized as highly susceptible. Correlation studies revealed that biophysical traits such as thicker leaves and higher trichome density were linked to greater resistance and reducing rate of defoliation.