D. melanoxylon seeds are vulnerable to high moisture level
Abstract: A study was conducted to investigate the effect of moisture and seed treatment on the in-situ and ex-situ regeneration of Dalbergia melanoxylon in Pugu forest reserve. Seed germination experiments was conducted for three months between November and December 2005 in the nursery Botany Department of the University of Dare s Salaam while seedling growth rate measurements were conducted for 12 months between January and December 2006 in the Pugu forest reserve. A total of 2 kg of D. melanoxy seeds collected from Pugu forest reserve and some from Tanzania Tree Seed Agency (TTSA) were used for seed germination experiments. A total of 25 seedlings approximately 2 years old were randomly chosen from Pugu forest reserve for seedling growth rate experiments. A split plot experimental design was used for seed germination in the nursery where soaked and non-soaked seeds stood for main plot and different moisture level treatments stood for subplot. Parameters recorded were germination dates, germination percentages, seedling increase in height and seedling increase in girth. Manual computation of data was accomplished according to Zar, 1988 where LSD was used for mean separation to determine statistical differences between treatment means. Tables and Figures were used to facilitate presentation and discussion of results. Data analysis led to the conclusion that, a moderate ex-situ moisture level of 200ml in a 1L pot per day effectively promoted seed germination up to 21% in seeds previously soaked in water for 6 hours compared to high moisture treatment of 300ml in a 1L pot per day which effected seed germination only by 11.6%.. The maximum in-situ growth rate was concluded to be 0.01 cm/month. The study revealed that seeds and young seedlings of D. melanoxylon are vulnerable to high moisture level while older trees are water and light demanding. It was recommended that future researches should endeavour to increase seed viability by harvesting them immediately from their maturity and storage in sealed containers, conducting tissue culture to manipulate seedlings and hybridization experiments with related species to reduce growth period
Ministry of Education Tanzania