A survey was carried out in the 1996/97 and 1997/98 growing seasons on a field planted in three replicates with five clones of cassava at the International Institute of Tropical Agriculture, Ibadan, located in a transition forest, to determine the effects of cassava genotype and climate on the development of African cassava mosaic geminivirus (ACMV) and changes in the Bemisia tabaci population. Cassava genotype, climate and their interactions have significant

A biological control program of water hyacinth was undertaken in Southern Benin between 1991 and 1993. It consisted of the release of three natural enemies, two weevil species and one moth, that feed exclusively on water hyacinth. In 1999, a survey of 365 men and women from 192 households in 24 villages in the target area, using participatory and quantitative methods, revealed that water hyacinth, although not eliminated, was perceived by the villagers as having been reduced from a serious pest ...

This article reviews improvements in important southern African food crops, and it describes the social and economic effects of those improved crops. Author Rodomiro Ortiz, the acting Deputy-Director General of the International Institute of Tropical Agriculture (IITA), says that the development and distribution of high-yielding cassava cultivars led to a 50 percent increase in average yield and a 10 percent increase in per capita output throughout Africa. Meanwhile, Ortiz says that improved maize ...

Improving the food quality of yams (Dioscorea spp) is an ongoing challenge to yam breeders and researchers. Forty accessions of D alata were evaluated for the suitability of their tubers for the preparation of two dominant food forms (boiled and pounded) as part of an effort to identify potential parents for use in genetic improvement. Trained panellists were presented with randomised, replicated and coded samples of boiled yam tuber pieces and asked to rate them for mealiness, colour, wetness, ...

Tuber dormancy enables yams to survive in the ground during the dry season and post‐harvest storage. Three clones of Dioscorea rotundata were harvested after five intervals and then stored in a cooler (20.6°C) or at ambient temperature (27.8°C). The time from harvest to sprouting was shorter as harvest was delayed. The period from sowing to sprouting for each clone was similar for tubers harvested from 140 days after planting, but tubers harvested earlier took longer to sprout. The cooler temperature ...

Large quantities of yam (Dioscorea rotundata), up to 30% of harvested tubers is usually reserved as planting material for the next crop. This experiment was conducted to assess the use of yam peels of Abi and Pepa yam varieties of 5-, 10-, 15-, and 30- to 40-mm thickness, for seed yam production. Pepa had poorer crop establishment and produced fewer but larger tubers than Abi

Soil organic matter (SOM) has an important effect on the physicochemical status of highly weathered soils in the tropics. This work was conducted to determine the contribution of different SOM fractions to the cation exchange capacity (CEC) of a tropical soil and to study the effect of organic matter inputs of different biochemical composition on the CEC of SOM. Soil samples were collected from a 20-year-old arboretum established on a Ferric Lixisol, under seven multipurpose tree species: Afzelia ...