Pollination Studies on Both Floret and Capitulum Levels in an Oil Seed Crop, Guizotia abyssinica (L.f.) Cass

Niger, Guizotia abyssinica (L.f.), is an important oilseed crop widely grown in Ethiopia and India, but poor pollination is one of the major constraints in achieving the yield potential of the crop. Our aim was to understand better the pollination biology and role of flower insect visitors in reproduction success. Results indicated that full anthesis occured in the morning between 06.00 and 08.00 h and pollen dehiscence eight to eleven hours after anthesis. Stigma receptivity commenced nine hours after anthesis and lasted for the next 24 h. A total of eighteen insect species representing six families visited Niger flowers, and among these, Apis florea and A. cerana were dominant. The flowers were self-incompatible as there was no seed set upon the selfing of floret and selfing of capitulum. The maximum seed set (78.33±0.14%) was noticed when flowers were allowed for open pollination and the lowest was recorded when the whole plant was caged to exclude pollinator visits (0.33±0.67). The time spent by A. cerana and A. florea was 1.35±0.48 and 1.83±0.12 seconds per floret, respectively and 9.63±0.69 and 14.9±0.94 seconds per capitulum, respectively. A. cerana and A. florea were found to be more efficient pollinators of G. abyssinica. Introducing bee colonies might greatly improve the yield, and it is also important to conserve bees in the vicinity of G. abissynica fields during the flowering period. Hence, introducing bee colonies might greatly improve the yield of Niger.