Assessing the role of honey bee (Apis mellifera L.) in the seed production of Brassica campestris var. toria in the Punjab

To assess the role of Apis mellifera honey bee in the seed production of Brassica campestris var. toria and to determine the number of honey bee colonies required for pollination of unit area, experiments were conducted during 2005–06 and 2006–07 crop seasons at PAU Seed Farm, Ladhowal (Ludhiana). The observations were recorded and the samples for the study were taken at 25 m interval distance of the crop upto 100 m during 2005–06 and up to 200 m during 2006–07 from one Apis mellifera (10 bee frame strength) colony. The proportion of pollen foraging bees was higher up to 50–75 m from the bee colony and was also higher in the morning and noon time than in the evening. The data recorded on the mean number of siliquae per plant, number of seeds per 20 siliquae, thousand seed weight, seed yield per plant and oil content revealed that the distance did not show significant effect on the number of seeds per 20 siliquae (207.06–263.06) during 2005–06 and 183.00–238.60 during 2006–07) and oil content (43.80–45.40% and 43.00–45.30% during 2005–06 and 2006–07, respectively). Mean number of siliquae per plant was significantly higher upto 50 and 75m distances during 2005–06 and 2006–07, respectively, number of seeds per plant upto 50m during 2005–06, thousand seed weight upto 100 and 75m distance and seed yield per plant upto 50 and 75m during 2005–06 and 2006–07, respectively. Thus, on overall, one colony of Apis mellifera with 10 bee strength was sufficient for effective pollination of the crop upto 50 distance around the colony. So it is concluded that the crop requires one Apis mellifera colony for realizing effective pollination of one hectare of crop area.