Seed Characteristics and Dormancy of some Exotic Tree Species in Sudan

Abstract

This work aimed at studying seed characteristics and dormancy braking methods of three exotic species to Sudan. these species are ,Casia siamea, Cassia fistula, and Tectona grandis the study aimed at investigating the phenomenon of dormancy in the seeds of the above mentioned species and methods to break it . The goal is produce the right information and the suitable techniques for forests department for a forestation and for those who are interested in tree planting to take part in the success of tree planting programs in the Suba. Fresh seeds collected in 2009 and used in this study to explore the seed characteristics, on percentage basis ,which include seed viability and germination, purity, moisture content, soundness, and number of seed per kilogram beside identification of kind of dormancy. Some pretreatments were applied for dormancy breaking of the three species under study, ,which include electric burner, sulphoric acid, cold and boiled water and stratification. The percentage germination test results were analyzed statistically using JMP package version 3.2.2 . The study concluded that all species had high viability percentage when using cutting test. The low moisture content test showed that the seed of the three species are orthodox (dry seeds). The response of C.fistula seed to suipharic acid 30 min and electric needle excelled all other treatments, followed by sulpharic acid for 15 min. The other treatments are either not significant versus control (cold water, sulpharic acid for 15 min.) or showing harmful effect (build water),so sulpharic acid) for 30 min ,and electric needle could be applied for bulk and small seed lots respectively, hot water should be avoided (harmful). The seed of C.siamea revealed high significant differences between treatments, the sulpharic acid for 30,15 5 minutes and electric needle gave the highest germination versus control. The cold water and boild water showed rather a negative response, hence su1pharc acid for 15 min cou1d be applied as a unique treatments while cold and boiled water should be avoided. Tectona grandis seeds were subjected to all treatments used above for the other two species followed by stratification and scarification but there was no response and not even a single seed germination was obtained. Because the time was limited for this study to go on testing seed of this species, further studies to determine the nature of dormancy and optimum methods for breaking it are recommended.