Comparative Study in Seed Yield and Flowers Attractivity to Bee Visitors Between Nigella Sativa L. and Nigella Damascena L. (Ranunculaceae) Grown Under Semiarid Conditions

This experiment was carried out during the growing season 2005 at the campus of Jordan University of Science and Technology (32°22” N, 35°49” E), Jordan. Two different Nigella species were used in this experiment; Nigella sativa L. and Nigella damascena L. This study was aimed to identify the bee visitors of Nigella species and the pollination requirements of Nigella flowers grown under semiarid conditions. The results showed that flowers of both Nigella species were visited by seven different bee visitors. However, flowers of N. damascena were more attractive to bees than N. sativa flowers. N. damascena produced on average significantly higher plant, more number of branches per plant, more seed yield, total seed weight and higher number of capsules per plant. On the other hand, N. sativa produced its flowers and matured nearly two weeks earlier than N. damascena. There is no interaction between Nigella species and pollination treatments for all yield parameter. N. damascena was higher in number of ovaries, seeds per capsules, seed set percentage, seeds per plant and total seed weight than N. sativa under treatments conditions. Also, flowers of both Nigella species under open treatment produced higher yield compared to other pollination treatments.