Studies on seed conservation and Propagation of the Neem Tree (Azdirachta indica a juss) in Sudan

Neem tree (Azadirachta indica A. Juss ) is a multipurpose tree widely planted in Sudan. Recently the tree has been singled as a high priority species for natural pesticide this gives it an economic importance. Fresh seeds germinate readily if sown directly after collection but they lose their viability very quickly (4-12 weeks). This study was conducted at the National Tree Seed Centre, Soba-Sudan (June-December 1995) and University of Gezira farm (Dec.94 -Jan.1996). The main objectives of the research work were: (i) To investigate the effect of storage temperature, ripening stage and fruit pulp (mesocarpe) on viability of neem seeds. (ii) To evaluate the success of establishment by planting nursery stock and direct sowing of neem seeds. For storage trials both whole fruits and clean seeds at different maturity stages (green, yellow and brown) were used. Storage temperatures tested were 4, l2°C and room temperature (30°C) for 24 weeks. Trials on vegetative propagation of neem using hardwood stem cutting treated with NAA and IBA at different concentrations (12000, 8000 and 4000 ppm) and control were also conducted. The results show that, fresh clean seeds have higher viability 84.0%, 73.33% and 14.67% compared to whole fruits 37.33% , 17.33% and 2.67% at different maturity stages green, yellow and brown, respectively. Yellow neem seeds shows the highest viability 52.03 after 20 weeks storage at room temperature (30°C). At storage temperatures (4 and 12 °C) low viability was obtained from both yellow and green seeds. Brown seeds and whole fruits of all ripening stages are not recommended for storage. Direct sowing gives no significant difference from transplanting. This method is recommended one because it is relatively less expensive. Hardwood stem cuttings of neem did not root under the conditions of the experiment.