Yogesh KumarNayak, Sudhanshu Bala2022-01-252022-01-252020https://krishikosh.egranth.ac.in/handle/1/5810181196The present investigation entitled “Role of insect pollinators towards yield attributing parameters of castor (Ricinus communis Linnaeus)” was carried out at Research Farm and Apicultural laboratory, Department of Entomology, CCS Haryana Agricultural University, Hisar on the two promising hybrids, GCH-7 and DCH-177 during Kharif of 2018 and 2019. A total of 36 insect species belonging to nineteen families of six different orders were recorded from the R. communis flowers. Among them, Hymenopterans occupied the dominant share (50%) followed by Lepidopteran (25%), Dipteran (11%), Coleopteran (8%), Hemipteran (3%) and Orthopteran (3%). Among them, 12 species were reported to be frequent visitors where as A. florea was the most abundant species followed by A. cerana, A. mellifera, and A. dorsata with abundance of 12.41, 4.73, 2.83 and 1.64 bees/m²/5min and the least abundant was Eristalinus sp. (0.28 bees/m²/5min) respectively. Hymenopterans were dominated as flower visitors of R. communis accounting 97.54 per cent of the total pollinators. Among them, four social bee species viz., A. florea (49.17%), A. cerana (18.76%), A. mellifera (11.21%) and A. dorsata (6.49%) were considered to be principal pollinators of castor. Insect visitors had followed the unimodal diurnal activity pattern with single visiting peak at 1000-1200 hours.With pertaining to duration of foraging, A. mellifera had highest working duration i.e. 10:39 hours: minutes .The foraging rate was found to be maximum in A. dorsata (6.79) followed by A. mellifera (6.03), A. cerana (5.39) and A. florea (5.07) Further, the lowest number of flowers was visited by Eristalnus sp. (2.33 flowers/minute). The foraging speed was recorded highest for A. cerana (6.26) followed by A. mellifera (5.12), A. dorsata (4.20), A. florea (3.74) lowest foraging speed was recorded for X. iridipennis (2.67 seconds/flower). While computing pollination index, the high pollination efficiency of social honey bees over the solitary bees was noticed. The average dry nectar sugar varied from 0.035 to 0.091 mg/flower and significantly the peak production were recorded during 1000-1200 hours. Effect of different modes of pollination on on qualitative and quantitative yield parameters of castor showed that the capsule setting (%), number of capsules per plant, total number of seeds per plant, 100 seeds weight, seed yield per plant, seed yield per hectare, seed germination (%), seed vigour I and II and oil content (%) were highest in case of open pollination (OP) as compare to bee pollination (BP) and without insect pollination treatment (WIP).EnglishThesis