Tropical fruit trees constitute important biological resources in the global agrobiodiversity context. Unlike the tropical fruit trees of American and Asian origin, indigenous fruit trees (IFT) of tropical Africa have scarcely achieved the status of international recognition in commodity markets and research arena outside Africa. This paper presented a critical review of the status of IFT in the Tropical African sub-regions (of West Africa, Central Africa, East Africa, Southern Africa and the Indian Ocean Islands) in relation to the introduced naturalised fruit trees from tropical America and Asia, threats to the diversity and sustainable use of IFT, analysis of the opportunities and challenges of developing IFT, as well as targets for crop improvement of the rich IFT of Tropical Africa. Domestication programme via relevant vegetative propagation techniques for priority IFT of the sub-regions was examined and advocated, in addition to the adoption of complementary conservation strategies, including Field GeneBanks in the management of the continent's IFT diversity.

Field experiments were conducted in the 1998 and 2004 cropping seasons to assess the impacts of different mulching materials on weed control, soil temperature, soil moisture depletion and performance of tomato (Lycopersicon esculentum Mill.) in Ibadan, a rainforest-savanna transition ecological zone of Nigeria. The crop growth and fruit yield were studied under plastic (grey-on-black), woodchip (Teak) and grass (Pennisetum) mulches, with handweeded and unweeded as controls in a randomized complete block design with three replicates. Also assessed were weed dry matter and species spectrum, soil temperatures at 5-cm and 15-cm depths, and soil moisture depletion. Compared to unweeded control that had the least total fruit yield (2.7 t/ha in 1998 and 4.2 t/ha in 2004), mulch types and handweeded treatments increased the fruit yield by 152-237% in 1998 and 188-202% in 2004. Compared to mean pooled fruit yield from all mulched plots, unweeded treatment reduced tomato fruit yield by about 65% and 66% in 1998 and 2004, respectively. The weed control efficiencies of the mulches ranged between 91% and 100%. Dicotyledon weed species dominated the plots in the two years accounting for 81.8% in 1998 and 90% in 2004. The number of low-growing weed species enumerated on the plots was 11 in 1998 and 18 in 2004. After four weeks of no rainfall in 1998, moisture loss was least (1.68±0.10%) under plastic mulch and highest (13.96±0.08%) on the unweeded plot. The differences between morning and afternoon soil temperatures at 5 cm depth were low under grass mulch, woodchip mulch and unweeded control (5.0-5.9 o C) but high under plastic mulch and handweeded control (8.7-8.9 o C). Mulches are effective in weed control and conservation of soil moisture, and the plant-based mulches are most effective in reducing soil temperature. These improvements of crop growing environment resulted in increased tomato growth and fruit yield.

Wetlands in Nigeria face constant threat of destruction by urbanization, road construction and agricultural activities, but the floristic compositions of these fragmented communities are unknown. A comparative 0 1 assessment study of the floral of three wetlands in a forest-savanna transition ecological zone, Ibadan (7 26 N, 0 1 3 54 E), Oyo State, Nigeria was conducted in the dry and wet seasons of 2002 to assess their species richness, density, community structure and diversity. Thirty-eight plant species from 19 families were enumerated in the three wetlands in two seasons. Nineteen species from 13 families were enumerated in the dry season, while 14 species belonging to nine families were enumerated in the wet season. Eight families were common to both seasons. Eleyele and Apete wetlands had relatively stable flora for both seasons, while Oba dam exhibited pronounced shift in flora between the dry and wet seasons. Continuous perturbation of the three wetlands encouraged proliferation and dominance of some invasive species at the expense of indigenous species populations, leading to subtle biodiversity erosion.

The effects of mulching material on okra performance during the rainy seasons of 1999 and 2000 were evaluated at the Teaching and Research Farm of the

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