International Institute of Tropical Agriculture

About: International Institute of Tropical Agriculture is a nonprofit organization based out in Ibadan, Nigeria. It is known for research contribution in the topics: Population & Agriculture. The organization has 2638 authors who have published 4330 publications receiving 119041 citations. The organization is also known as: IITA.

Cowpea plant architecture in relation to infestation and damage by the legume pod borer maruca testulalis geyer lepidoptera pyralidae i. effect of canopy structure and pod position

Abstract: The effects of cowpea, Vigna unguiculata (L.) Walp. canopy structure and pod position in relation to infestation and damage by the legume pod borer, Maruca testulalis Geyer were investigated. Defoliated cultivars sustained significantly less infestation and damage (P < 0.05) than those undefoliated. Relative humidity measured under the canopy was lower in defoliated cultivars, while soil and ambient temperatures were higher. Percentage pod damage and larval infestation by M. testulalis in flowers were positively correlated with relative humidity, and negatively correlated with temperature. Both correlations were significant (P <0.01). Cultivars with pods held within the canopy suffered significantly more damage (P <0.05) than cultivars whose pods were held in the normal position. Canopy structure and pod position acting together or independently, exerted profound effects on cowpea resistance to M. testulalis. Selection and breeding cowpea cultivars with less dense foliage (= open canopies) and long peduncles holding the reproductive structures above the canopy, should increase cowpea resistance to M. testulalis.

Food availability and livelihood strategies among rural households across Uganda

Abstract: Despite continuing economic growth, Uganda faces persistent challenges to achieve food security. The effectiveness of policy and development strategies to help rural households achieve food security must improve. We present a novel approach to relate spatial patterns of food security to livelihood strategies, including the contribution of on- and off-farm activities to household food availability. Data from 1927 households from the World Bank Living Standards Measurement Study were used to estimate the calorific contribution of livelihood activities to food availability. Consumption of crops produced on-farm contributed most to food availability for households with limited food availability, yet the majority of these households were not food self-sufficient. Off-farm and market-oriented on-farm activities were more important for households with greater food availability. Overall, off-farm income was important in the north, while market-oriented on-farm activities were important in western and central Uganda. Food availability patterns largely matched patterns of agroecological conditions and market access, with households doing worst in Uganda’s drier and remote northeast. Less food-secure households depended more on short-cycle food crops as compared with better-off households, who focused more on plantation (cash) crops, although this varied among regions. Targeting interventions to improve food security should consider such differences in enterprise choice and include options to improve household market access and off-farm income opportunities.

A High-Throughput Regeneration and Transformation Platform for Production of Genetically Modified Banana.

Abstract: Banana (Musa spp.) is an important staple food as well as cash crop in tropical and subtropical countries. Various bacterial, fungal, and viral diseases and pests such as nematodes are major constraints in its production and are currently destabilizing the banana production in sub-Saharan Africa. Genetic engineering is a complementary option used for incorporating useful traits in banana to bypass the long generation time, polyploidy, and sterility of most of the cultivated varieties. A robust transformation protocol for farmer preferred varieties is crucial for banana genomics and improvement. A robust and reproducible system for genetic transformation of banana using embryogenic cell suspensions (ECS) has been developed in this study. Two different types of explants (immature male flowers and multiple buds) were tested for their ability to develop ECS in several varieties of banana locally grown in Africa. ECS of banana varieties ‘Cavendish Williams’ and ‘Gros Michel’ were developed using multiple buds, whereas ECS of ‘Sukali Ndiizi’ was developed using immature male flowers. Regeneration efficiency of ECS was about 20,000-50,000 plantlets per ml of settled cell volume (SCV) depending on variety. ECS of three different varieties were transformed through Agrobacterium-mediated transformation using gusA reporter gene and 20-70 independent transgenic events per ml SCV of ECS were regenerated on selective medium. The presence and integration of gusA gene in transgenic plants was confirmed by PCR, dot blot, and Southern blot analysis and expression by histochemical GUS assays. The robust transformation platform was successfully used to generate hundreds of transgenic lines with disease resistance. Such a platform will facilitate the transfer of technologies to national agricultural research systems (NARS) in Africa.

Bananas and Plantains (Musa spp.)

Abstract: Bananas and plantains are one of the most important crops in the world, yet very few hybrids are cultivated. Bananas face considerable pressure from multiple biotic and abiotic stresses, but its genetic improvement is impeded by constraints on seed set due to multiple physiological and reproductive issues. The triploid nature of almost all commercially important bananas requires a complicated breeding scheme involving cross hybridization across ploidy levels and results in poor seed set that reduces the probability of obtaining favorable recombination. The poor seed set is further complicated by issues of parthenocarpy and partial to complete female and male sterility that are not fully understood. While the introduction of genomic resources of this perennial long cycling crop promises to hasten the development of improved cultivars, there is a need to maintain vigorous and committed long-term international breeding programs.

Conversion of Tropical Rainforest: Agronomic Potential and Ecological Consequences

Abstract: Publisher Summary This chapter describes the agronomic potential and ecological consequences of conversion of tropical rainforest. Tropical rainforest refers to the climax vegetation of the lowland humid tropics where there is either a short period of water deficit or none at all. Tropical rainforest is confined to the equatorial region and is a very diverse and complex ecosystem. Soil is an integral element of the rainforest ecosystem and is as much influenced by the vegetation as the vegetation itself is influenced by the soil. Soils supporting tropical rainforests are usually old, highly weathered, and excessively leached. Estimates of forest conversion in the Brazilian Amazon, in tropical Africa, and in the tropics are presented. Possible local effects of deforestation on biophysical environments are explained. Major effects are on microclimate, water and energy balance, nutrient capital with disruption in pathways of various nutrient elements, soil, flora and fauna composition and activity. Deforestation for intensive land use is an important factor in forest conversion. Methods of deforestation vary widely depending on the intended cropping systems, and soil and crop management methods. It is suggested that forest conversion for plantation crops should also be preferably done by manual, and slash and burn methods.