Physiological and Agronomic Responses of Four Rice Varieties to Drought in the Rainforest.

The present investigation tested the hypothesis that there would be variation in physiological responses to water deficit among rice varieties from different production ecologies, with contrasting tolerance to water deficit under repeated cycle of soil moisture deficit, at reproductive growth stage. A screen house and a field trial were conducted at International Institute of Tropical Agriculture, Ibadan and Ikenne (Latitude 6° 52' N, Longitude 3° 43' E) respectively. Both experiments had rice varieties ('IR 64', 'WAB 56-104', 'IR 77298-1-2-B-10' and 'NERICA 4') and stress status (stress and control) as treatment factor's, arranged in a randomised complete block design with three replicates. In both trials, the physiological mechanism that underpins varietal differences with repeated cycles of water deficit at the reproductive growth stage was more balanced water status, improved foliar characters, efficient photosynthetic capacity and higher grain yield in comparatively drought tolerant upland rice varieties ('NERICA 4' and 'WAB 56-104'), as opposed with the results for the drought susceptible cultivar 'IR 64'. A converse pattern was observed on water stressed rice, despite fewer cycles of water deficit on the field. The results could have suggested that the initiation of water deficit is the rate limiting step rather than its intensity at the reproductive growth stage

Genetic Diversity of Selected Upland Rice Genotypes (Oryza sativa L.) for Grain Yield and Related Traits

Seventy-seven upland rice genotypes including popular cultivars in Nigeria and introduced varieties selected from across rice-growing regions of the world were evaluated under optimal upland ecology. These genotypes were characterised for 10 traits and the quantitative data subjected to Pearson correlation matrix, Principal Component Analysis and cluster analysis to determine the level of diversity and degree of association existing between grain yield and its related component traits. Yield and most related component traits exhibited higher PCV compared to growth parameters. Yield had the highest PCV (41.72%) while all other parameters had low to moderate GCV. Genetic Advance (GA) ranged from 9.88% for plant height at maturity to 41.08% for yield. High heritability estimates were recorded for 1000 grain weight (88.71%), days to 50% flowering (86.67%) and days to 85% maturity (71.98%). Furthermore, grain yield showed significant positive correlation with days to 50% flowering and number of panicles m-2. Three cluster groups were obtained based on the UPGMA and the first three principal components explained about 64.55% of the total variation among the 10 characters. The PCA results suggests that characters such as grain yield, days to flowering, leaf area and plant height at maturity were the principal discriminatory traits for this rice germplasm indicating that selection in favour of these traits might be effective in this population and environment

Gestion des forlts inondées dans le Delta Interieur du Niger, Mali; management of flood forests in the Inner Niger Delta, Mali

Flood forests of Acacia kirkii in the Inner Niger Delta, Mali, host large mixed colonies of waterbirds and play a key role in the production of fish fry and the fertilization of surrounding fields. These forests were managed in a sustainable way by local people, until many were destroyed during the drought periods in the 1970s and 1980s. Local populations wish to regenerate these forests, but without outside assistance they fail to do so, due to conflicts of interest

Characterization of maize producing communities in Benin, Ghana, Mali, and Nigeria: West Africa Regional Synthesis Report

Maize is becoming increasingly important as a food security crop in West Africa. However, recurring droughts constitute a continuous challenge to its production. Attempts at addressing the drought problem resulted in the conduct of a participatory community survey of maize production systems with about 20–40% probability of drought risk in four DTMA countries (Bénin Republic, Ghana, Mali, and Nigeria). The project is part of an initiative to develop and disseminate appropriate drought tolerant maize varieties in sub-Saharan Africa. The main objectives of the community survey were to complement household survey data, capture essential qualitative information and data that are difficult to obtain through formal household surveys, and serve as a pilot application for potential expansion through the African region. The survey was conducted in selected communities in two districts with high levels of maize production in each of the DTMA countries. Results show that maize is a major source of food and cash for smallholder farmers. Community members indicated that both positive and negative changes have taken place in the subregion over the 10-year period. Among these, the introduction and adoption of new DT maize varieties have contributed to achieving food security and poverty reduction, as well as enhanced livelihoods for the people. However, appropriate and adequate provision of production inputs (such as fertilizers, good quality seeds, and herbicides) is essential for achieving the optimum yield of DT maize. Constraints to production include long distances to input markets and the consequent high costs of transportation that make it very difficult for most farmers to get access to inputs. Bad road networks, lack of good quality drinking water, and poor health facilities which are common problems faced by farming households are also detrimental to agricultural productivity. Women in the subregion are also committed to farming but constrained by cultural and religious factors. Women have special roles such as in the cultivation of oil seed crops and vegetables on small parcels of land to provide additional income to the household. Thus, making men within farmers’ organizations more aware and appreciative of the value of women’s contributory role in the household will further help to achieve improved food security in the region

Characterization of maize producing households in the dry savanna of Mali

Maize is one of the three most important staple foods in Mali. Zones in the country with high potential for producing maize are limited to areas where the probability of drought risk is between 20 and 40%, meaning that recurring droughts have long handicapped maize production. In an attempt to alleviate drought stress on maize production, a household survey was conducted in the two Local Government Areas of Bougouni and Koutiala, both in the Sikasso Region, during the 2007/2008 production period. These two districts were selected following an environmental characterization of drought zones in Mali. The survey was mainly oriented towards maize based farming systems. Six sample villages were selected within each of the two districts. The sample population was defined as maize farming households. A total of 150 households were randomly selected and interviewed with structured questionnaires. Interviews were conducted by trained enumerators using a formal household survey. The purpose of the study is to provide both quantitative and qualitative feedback from farmers to researchers and to the B&MGF on the impact that improved maize varieties developed in the past have had upon the livelihoods of households and to provide a detailed database for the projection of expected outcomes with the deployment of new drought tolerant maize varieties under the B&MGF drought tolerant maize project. Both qualitative and quantitative analyses were used to extract from our set of variables those orthogonal linear combinations of the variables that best captured the common information. Most successful was the one proposed by Filmer and Pritchett (1998; 2001) called the Principal Component Analysis (PCA). To assess the variables affecting the adoption of improved maize varieties, the Tobit model was used. The results show that 99% of household heads are male. The size of a household is 22 persons, on average. About 47% of the household’s members are available for farm work. About 59% of household heads are illiterate, an important factor concerning the adoption of new technology. These household heads make decisions about 84% of farming activities; 86% of the households involved in the study belonged to at least one farmers’ organization in order to have easy access to inputs

Yield loss of Oryza glaberrima caused by grain shattering under rainfed upland conditions

The general perception of Oryza glaberrima as low yielding is a potential drawback to intraspecific breeding of this species. Yields of 21 O. glaberrima accessions were evaluated alongside four O. sativa check varieties under two conditions in which panicles were both covered by paper sacks to avoid grain shattering (potential yield plot) and also not covered (control plot) in a rainfed upland field of Benin in 2010 and 2011. Average potential yields of O. glaberrima with panicles covered were 2.42 and 3.65 t ha-1 in 2010 and 2011, respectively, while those of O. sativa were respectively 2.99 and 3.49 t ha-1. Although there was no significant difference between potential yield and control yield in O. sativa, 19 O. glaberrima accessions showed significant yield reduction by grain shattering — the average percentages of lost yield by shattering were 57.88% in 2010 and 66.76% in 2011. These results suggest that low yield of O. glaberrima is due to grain shattering and that its potential yield would not be inferior to O. sativa if the grain shattering problems were overcome. Two O. glaberrima accessions, TOG 12303 and TOG 9300, possessing strong resistance to grain shattering comparable to O. sativa checks, were identified.Keywords: Panicles, paper sacks, potential yield, yield reduction