أثر الموقع الجغرافي والشجرة الأم على بذور وإنبات ونمو شتلات السنط

Abstract

The objectives of this study were to study Acacia nilotica (Sunt) seed characteristics; effect of geographical location and mother-tree on seed, germination and seedling growth and the effect of seed weight on germination and seed vigor. Three experiments were conducted. In the first experiment, seed lots of sub species nilotica and tomentosa were obtained from Eldamazain (Blue Nile state) and South Kordofan, respectively. Seed length, diameter, thickness, weight, seed coat weight were measured. The weight ratios of seed coat and embryo to seed were calculated. For the second experiment, three locations were identified along the Blue Nile which were Elgazair, Lowni and Abu Ramad forests. Fruits were collected from twenty trees (mother-trees) taken randomly in each forest. Fruit, seed, seed germination and seedling growth were evaluated per mother-tree and location. Seedling growth was evaluated after 11, 25, 39 and 53 days from sowing date. In the third experiment, combined seed lot from the three locations was divided into three groups according to weight (heavy, medium and light) and the germination and seedling growth were evaluated for each group. The results, of the first experiment, showed significant variation in seed weight, length, diameter and thickness according to weight groups for subspecies nilotica and tomentosa. Differences between weight groups were not significant in weight ratios of seed coat to seed. The ratios of seed coat to seed were 57% and 61% for the subspecies nilotica and tomentosa, respectively. Strong correlations were obtained for seed weight with embryo weight and seed coat weight. Inverse strong correlations were obtained between seed coat weight and embryo weight. The second experiment revealed significant differences between location in fruit length, number of seeds per fruit, and the length of constrictions between seeds in the fruit. Also, significant differences were obtained in seed weight and seed length. The differences were between the locations that are different in distance and rainfall. The effect of mother tree was significant on fruit length, fruit diameter and number of seeds per fruit. The effect of mother-tree was significant on some seedling growth parameters at Abu Ramad and Lowni while no differences were observed at Elgazair. Strong correlations were obtained between total seedling weight with shoot weight, root weight and stem length. The third experiment revealed no effect for seed weight on germination and seedling growth.