Screening of Mustard Brassica juncea Varieties for Resistance against Aphid Lipaphis erysimi Kaltenbach and Understanding the Genetic Diversity among Mustard Aphids collected from Rajasthan

Abstract

newline This study on title Screening of Mustard (Brassica junea) Varieties for newlineResistance against Aphid, Lipaphis erysimi (Kaltenbach) and Understanding the newlineGenetic Diversity among Mustard Aphids collected from Rajasthan at the newlineinstructional farm of Rajasthan College of Agriculture, Udaipur, Rajasthan, during the newlineRabi 2022-2023 and 2023-2024 growing seasons. newlineDuring the 2022-2023 season, aphid populations in 15 mustard (B. juncea) newlinevarieties ranged from 23.20 (Pusa Bold) to 146.07 aphids/10 cm portion (PBR-210), newlinepeaking in early January with PBR-210 at 255 aphids. By harvest, Aravali had the newlinelowest (1.33) and PBR-210 the highest (20.60). In 2023-2024, aphids appeared in late newlineDecember, peaking again in January with PBR-210 at 255.40 aphids. Aravali newlinerecorded the lowest aphid count at harvest (1.33), while PBR-210 had the highest newline(20.60). Overall, Pusa Bold had the lowest average population (26.86 aphids/10 cm newlineportion). In the 2022-2023 study, trichome density showed a weak, non-significant newlinecorrelation with aphid populations on both upper (r = 0.075) and lower (r = 0.182) newlineleaf surfaces. Total phenol (r = -0.677) and glucosinolate (r = -0.561) contents had newlinestrong negative correlations with aphid infestation, indicating their protective role. newlineWax content showed a weak negative correlation (r = -0.014). In 2023-2024, similar newlineweak, non-significant correlations were observed for trichome density (upper: r = newline0.064, lower: r = 0.175). Total phenol (r = -0.580) and glucosinolate (r = -0.690) had newlinestrong negative correlations with aphid populations, while wax content showed a newlineweak but significant negative correlation (r = -0.019), confirming their role in newlineresistance.In 2022-2023, mustard aphid populations ranged from 54.24 to 113.33 newlineaphids/10 cm portion in protected sets, with DRMR-150-35 having the highest newline(113.33) and RH-725 the lowest. In unprotected sets, DRMR-150-35 (180.83) and PM-0031 (171.83) had the highest, while Giriraj had the lowest (98.51). Yield losses newlineranged from 21.47% to 34.09