Department of Entomology, Himachal Pradesh Krishi Vishvavidyalaya, Palampur-176 062, Himachal Pradesh, (India).
1Department of Chemistry and Biochemistry, College of Basic Sciences, Himachal Pradesh Krishi Visvavidyalaya, Palampur-176062, Himachal Pradesh, (India).
Ten varieties/strains of cruciferous oilseeds viz., Brassica campestris, B. napus and B. juncea were evaluated in the field for their reaction to three aphid species, viz., Lipaphis erysimi Kalt., Brevicoryne brassicae Linn. and Myzus persicae Sulzer. The screening revealed that B. napus and B. Juncea were relatively less susceptible as compared to B. campestris. The varieties P-19, Varuna, Emma, P-24, P-17 and white glossy were relatively resistant vis-a-vis the highly susceptible BSH-1 to different aphid species. Varuna (B. Juncea) and Wester (B. napus) possessed hardy slender inflorescence and loosely packed buds in comparison to tender infloresence and thickly packed buds in BSH-1 (B. campestris). Protein content showed positive but weak correlation with aphid population on leaf. Higher protein content was obtained in variety Wester (5.88%) and lower in Emma (3.52%). Phenol content ranged from 2.45% in P-24 to 3.23% in Emma in leaf and 2.05% (P-24) to 2.83% (White glossy) in cake. The population of aphid was negatively associated with phenol content both in leaf and cake. Oil content in different varieties varied from 24.55 in Nigra to 35.40 per cent in Wester. A low positive correlation was evident between aphid population and oil content indicating that varieties having higher and oil content supported higher aphid population leading to varietal susceptibility. The highest ash content was detected in Wester (5.9%) and the lowest in white glossy (4.4%) indicating a positive but low correlation between ash content of leaf and aphid population.
