Yield and quality of hybrid seeds: influence of honeybee visitations on various sterile male rows in sunflower

Investigations were carried out in Indo-Gangetic Plains to determine the in fluence of honeybees (Apis dorsata and A. mellifera) visitations on yield a nd quality of hybrid seed harvested from the eight sterile male rows indivi dually in 1:8 (R:A) planting ratio in sunflower (Helianthns annuus L.) duri ng the crop period of February to May, 1994 and 1995. The parental lines (R :MRH-1 and A:207A) of sunflower hybrid LSH-3 were maintained at a distance of 60 and 30 cm between and within rows, respectively. A significant (P<0.0 5) variation was observed among the eight sterile male rows for the abundan ce of both the honeybee species, loose sunflower pollen gains/bee, pollinat ion efficiency index (PET) per bee, hybrid seed yield as well as its qualit y. Rows of sterile male parent which were in proximity (up to 5th row) to t he male parent gave higher total hybrid seed yield/capitulum due to greater flow of pollens (r = 0.94) - as a result of higher bee abundance and incre ased PEI (r = 0.93). The number of unfilled seeds were also higher in capit ulum harvested from these sterile male rows. In contrast, hybrid seed harve sted from 6th, 7th and 8th row though produced less number of seeds/capitul um, due to poor bee abundance and lower PEI, yet had maximum number of fill ed and least unfilled seeds besides having maximum 100 seed weight. The qua lity of such seeds was also significantly better than those seeds harvested from sterile male rows raised adjacent to the fertile male parent. Utiliza tion of hybrid seed harvested from various sterile male rows is discussed.