BIOINFOLET - A Quarterly Journal of Life Sciences

The field experiments were carried out at ‘Instructional Farm ’of Bidhan Chandra Krishi Viswavidyalaya at Jaguli, Nadia, West Bengal, India during Rabi season of 2007–08 to 2008–09, to identify the various species of insect pollinators including honeybees and their peak visiting hours in a day as well as effect of different pollinating methods on yield of B-9 (Benoy) and B-85 (Seeta), varieties of rapeseed-mustard. Seventeen major insect pollinators, belonging to 5 orders, 12 families and 14 genera were observed visiting sunflower capitulum. Amongst the genera, Apis was found to be the most dominant visitor and A. mellifera was recorded to be most dominant pollinator. The foraging rate of the insect pollinators/m²/hour was highest during forenoon (1100–1200 h), followed by 0800-0900 h and 1500–1600 h. The effect of different pollination methods on yield of rapeseed-mustard differed significantly from each other. The number siliquas/m², number seeds/siliqua, weight of 1000 seeds (g) and yield (q/ha) was 727.06, 5463.33, 4.27 and 10.92 in var. Seeta and 744.00, 5194.83, 4.03 and 9.30 in var. Benoy, respectively. It was significantly higher in bee pollination (BP) followed by natural pollination (NP) while lowest was recorded due to self pollination (SP). There was 198% and 210.45% increase in the yield of rapeseed-mustard (in var. Seeta and Benoy respectively), when the crop was pollinated by bees, followed by 130.34% and 127.01% in the treatment with NP, as compared to SP