Impact of Genotype, Planting Date, Plant Density and Inflorescence Type on Bee Abundance and Seed Production in Broccoli

Field experiment was conducted in 2011-2012 to study the impact of genotype, planting date, andinflorescence type on bee abundance and seed production of broccoli in Ismailia Governorate. The abundance of twoselected bee species, Apis mellifera L. and Colletes lacunatus Dours was estimated on two cultivars of broccoli, Sultanand Marathon in two different planting dates and two types of inflorescences (primary and secondary). Results indicatedthat both A. mellifera and C. lacunatus significantly increased the pollination percentage. Bee abundance wassignificantly at the maximum level at 11.00 am-1.00 pm, all over the weeks of observation, followed by the previoustime of observation, at 9.00-11.00 am, then decreased significantly at 1.00-3.00 pm to reach the lowest abundance 3.00-5.00 pm. Also, results indicated that C. lacunatus was the dominant pollinator and had more intensity visitation than A.mellifera on the both cultivars. Generally, Marathon tends to give more fruit number and weight and accordingly moreseeds of light weight. On the other hand, Sultan has a tendency to give less seed number of heavier weight. The primaryinflorescence gave less number of flowers and consequently less number of fruits than secondary inflorescence, butthose fewer fruits gave less number of seeds with heavier weight. The effect of planting density on seed production wasdue to differences in number and destination of transported pollen grains. Planting date showed a profound influence onthe potential of seed yield. This study demonstrated that bee pollination could significantly improve both the yield andthe quality of seeds in broccoli under Ismailia conditions.