Screening of Mulberry Germplasm for Response to Seasonal Thrips Infestation

Abstract

The study was conducted during 2024–25 at the Department of Sericulture, UAS, GKVK, Bengaluru, to evaluate the seasonal incidence of thrips and identify resistant accessions among one hundred mulberry accessions. Thrips populations were recorded under natural field conditions during rabi, summer and kharif seasons at 15, 30, 45 and 60 days after pruning (DAP) and accessions were categorized into resistant, moderately resistant, susceptible and highly susceptible categories based on mean thrips counts. Results showed clear and significant differences in thrips infestation among the accessions across the seasons. Thrips infestation was highest during summer, moderate in rabi and lowest during kharif, mainly due to variations in temperature, rainfall and humidity. Thrips population peaked at 45 DAP when tender foliage was abundant and declined at 60 DAP as leaves matured. Although many accessions showed resistance in individual seasons, none remained completely resistant throughout the year. Pooled seasonal analysis identified four accessions viz., ME-86 (13.54), ME-01 (13.29), ME-52 (11.83) and M-66 (11.75) as consistently moderately resistant in all three seasons, indicating stable tolerance. Two accessions, ME-18 (19.96) and ME-84 (16.47), remained susceptible, while six accessions viz., MI-79 (34.63), MI-524 (26.25), MI-517 (23.08), MI-32 (31.54) and MR-2 (36.46) were consistently highly susceptible across all seasons. The research confirms considerable genetic variability for thrips tolerance and highlights the strong influence of seasonal climate on thrips dynamics, underscoring the need for season-specific management strategies and the importance of stable resistant accessions in breeding programmes.