diversity of insect pollinators and their effect on the crop yield of brassica juncea l., npj-93, from southern west bengal

Research Article
Bhowmik, B., Mitra, B and Bhadra, K
Brassica juncea L. NPJ-93, ecosystem services, pollination efficiency, pollen viability, seed yield

Study was carried out from the end of 2011 till mid of 2013, from South Bengal region, to explore the diversity of insect pollinators of Brassica juncea and their influence on the seed yield and quality. Insect flower visitors / pollinators were recorded at time periods starting from 07.00 to 17.00 hrs. 19 insect species belonging to 13 families under 4 orders viz. Hymenoptera, Coleoptera, Diptera and Lepidoptera, were recorded at the day time, among which 4 species (Apis dorsata, A. cerena, A. mellifera and Vespa sp.) were both pollen and nectar collectors, 14 species were only nectar collectors and rest of them were just, visitors. Peak activity of the insects was mainly observed from 11 am till 2 pm. Qualitative and quantitative effects of pollination on the percent fruit set; number of seeds per siliqua and mean weight of 100 seeds were compared in controlled and open pollinated plants and were reported to be significantly (P<0.01) higher in open pollinated viz., 6.41, 52.80 and 240, respectively. Further, pollination increases the germinability of the resulting seeds to 36 ± 3 %. Lower seed yield was assumed to be probably due to the availability of less number of viable pollen.