Variation in reproductive efficiency and yield of cowpea under high temperature conditions in a Sahelian environment

Fifteen cultivars differing in plant type and maturity were evaluated for their reproductive efficiency and yield at the ICRISAT Sahelian Center, in Niger in 1988, 1989 and 1990. Flowers and pods were used to determine the reproductive efficiency and yield differences were assessed by using crop growth rate and partitioning. Significant differences among cultivars were observed for their ability to flower and set pods under high temperature conditions. The pattern of flowering and pod set showed that flowers formed in the first 10 days after initial flowering had the highest percentage pod set. Potential pod set ranged from 5 to 81%. TN88-63, the most widely adapted cultivar in the Sahel averaged 59% pod set followed by A73-2-1 with 56%. There was considerable variation among cultivars in the duration of the reproductive period, crop growth rate and partitioning. Crop growth rate was largely responsible for differences in yield among cultivars

Intercropping Morphologically Different Cowpeas With Pearl Millet in a Short Season Environment in the Sahel

The effects on yield of varying the planting date and planting pattern of morphologically different cowpea cultivars intercropped with pearl millet were studied in two field trials. The interaction between cowpea cultivars and planting date was highly significant. There was a sharp reduction in cowpea yields with late planting. Millet yields were reduced less when sown simultaneously with early cowpea cultivars than when sown with a late maturing local cultivar. Early maturing cowpea cultivars planted in closely spaced hills had less effect on millet yields than a late maturing cultivar sown in widely spaced hills. An appropriate cowpea cultivar for intercropping with peal millet would be one that was weakly competitive and that yielded both grain and fodde

Evaluation of cowpea cultivars for intercropping with pearl millet in the Sahelian zone of West Africa

Field trials were conducted at ICRISAT Sahelian Centre, Niger, to examine the performance of contrasting cowpea cultivars intercropped with pearl millet. Significant effects (P ≤ 0.05) of cropping system and cultivars were observed for cowpea grain yield. Cultivar × cropping system interaction was significant only for fodder yield. Intercropping reduced cowpea yields significantly but the degree of reduction varied among cultivars. Early-maturing erect cultivars exhibited greater yield reduction than the indeterminate spreading types and had the least effect on millet yields. Indeterminate spreading cultivars produced greater grain and fodder yield than erect types and caused the greatest millet yield reduction. The relationship between the yield of cowpea cultivars and millet when intercropped was negative. Linear correlations between yield of cowpea in sole and intercrop were positive and significant (P < 0.01) with r values ranging from 0.45 to 0.91. However, a small proportion of the greatest and least-yielding cowpea cultivars in intercropping would have been selected and rejected, respectively, on the basis of sole-crop grain-yield. It was concluded that selection of cowpea cultivars for intercropping with millet based on their grain yield in sole crop may have limited success. Selection based on fodder yield favoured late-maturing cultivars. Selection of cowpea cultivars for intercropping should be based on their intercropped performance, paying special attention to other agronomic factors. An appropriate cowpea cultivar for intercropping with millet would be the one that is less competitive with millet and yields both grain and fodde

Dissemination and end-of-project workshop on “Development of Sustainable Seed Systems in West Africa” held in Bamako, Mali

Funded by the Common Fund for Commodities (CFC), the 4-year Groundnut Seed Project (GSP) entitled “Development of sustainable groundnut seed systems in West Africa” was concluded on 30 June 2007. The International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), as project executing agency (PEA), organized an end-of-project final workshop from 2 to 3 July 2007 at Bamako, Mali. The objective was to present the achievements of the project to a wide range of stakeholders

Early generation testing for yield and physiological components in groundnut (Arachis hypogaea L.)

Selection of superior crosses of groundnut (Arachis hypogaea L.) in early generations would increase the probability of identifying superior lines. The objective of this study was to determine the potential of selecting for physiological traits identified in a yield model [crop growth rate (C), reproductive duration (DR) and partitioning (p)] in segregating populations. Forty populations and nine parental lines were evaluated in replicated trials in 1992 (F2, 1993 (F3) and 1994 (F4) at three locations in Niger. Physiological traits were estimated from final yield and biomass as well as data on flowering and maturity. Regressions from two different parent-offspring generations (F2: F3 and F3: F4) were calculated. The results were compared to determine if early generation performance accurately predicts the performance of cross bulks in later generations. Differences were observed among populations and parents for all traits. Effects of locations were significant for C, p and DR in F2 and F3 but nonsignificant for yield and C in F4. Regression coefficients from F3: F2 were 0.10 ± 0.08 for C, 0.45 ± 0.17 for p, 0.10 ± 0.03 for DR and 0.16 ± 0.03 for pod yield. Based on F3: F4 regression, the coefficients were 0.12 ± 0.23 for C, 0.46 ± 0.17 for p and 0.57 ± 0.17 for yield. Parent-offspring correlations were in most cases similar to the regression values. It was concluded that selection for yield and model components in early generation bulks may inneffective

Effects of phosphorus on yield of cowpea cultivars intercropped with pearl millet on Psammentic paleustalf in Niger

Phosphorus (P) is the most limiting soil nutrient in the sandy soils of Niger and farmers rarely use chemical fertilizers in producing pearl millet and cowpea. A 3-yr study was conducted in farmer's fields at two locations in South Western Niger to investigate yield response of six cowpea cultivars to applied P-fertilizer (0, 8, 16 kg ha(-1)) when intercropped with millet. Significant yield differences were found between cultivars for their seed and dry fodder yield at all rates of applied P. Cultivars responded differently to the application of P. Millet grain was more than doubled with the addition of 8 to 16 kg P ha(-1). Cowpea cultivars did not have significant differential effect on millet yields. Cowpea cultivars differed significantly in the accumulation of P in fodder with the highest yielding cultivars taking up more P than the low yielding ones. The results have important implications for breeding and selection of cowpea cultivars that are adapted to a range of fertility levels

Rotation and nitrogen fertilizer effects on pearl millet, cowpea and groundnut yield and soil chemical properties in a sandy soil in the semi-arid tropics, West Africa

A 5-year study was conducted from 1988 to 1992 at three sites in Niger to determine the effects of crop rotation of a cereal and legumes and nitrogen fertilizer on chemical properties of the soil (0-20 cm) and yield of pearl millet (Pennisetum glaucum), cowpea (Vigna unguiculata), and groundnut (Arachis hypogaea). Four N levels (0-45 kg N/ha) and rotation treatments including continuous fallow were investigated. Soil samples taken from the top 20 cm depth at the end of the experiment from treatments without nitrogen application which included continuous fallow, fallow-millet rotation, groundnut-millet rotation, cowpea-millet rotation, and continuous millet were analysed for soil pH, organic carbon, total nitrogen and exchangeable bases. Fertilizer N significantly increased yield of pearl millet, cowpea and groundnut. Continuous monocropping of pearl millet resulted in lower yields across N levels compared to legume-millet rotations. Legume yields were also consistently lower in monoculture than when rotated with millet. There was a decline in organic matter under continuous millet, cowpea-millet rotation and groundnut-millet rotation. The fallow-millet rotation supplied more mineral N than the legume-millet rotations. Nitrogen availability was greater in cowpea-millet rotation than continuous millet. Crop rotation was more productive than the continuous monoculture but did not differ in maintaining soil organic matter. The legume-millet rotation at 30 kg/ha N appears to be the most viable for millet production. Research should focus on understanding the effect of legume/cereal intercrops and rotations on soil productivity

Groundnut seed systems in Senegal and Niger

The informal seed systems in Senegal and Niger are described. These systems still remain the main seed sources for almost all small-scale holder farmers in both countries. The systems perform fairly well at supplying seeds to end-users, distributing seeds at relatively low cost, and maintaining acceptable levels of seed viability and health. A tabulated list of groundnut varieties released in Niger and Senegal is provided. The trends in commercialized production of groundnut seeds in Niger and Senegal are presented

Selection of cowpea cultivars for cool-season production in the Sahel

Cowpea (Vigna unguiculata (L.) Walp.) is traditionally grown during the short rainy season in the Sahelian zone of west Africa, but there are opportunities for dry-season production providing the problems of low night temperatures can be overcome. The objective of this research was to identify cultivars suitable for irrigated cropping during the cool post-rainy season. Four hundred and thirtytwo lines representing breeding and local germplasm lines from Niger were tested for field emergence, flowering and podding in the coolest time of the year. A selected set of lines was evaluated for yield and other characteristics. Seedling emergence began 8 days after sowing and seedlings emerged over a 7-day period. Seventy-four percent of the local germplasm lines recorded 76–100% emergence as compared to 4% of the breeding lines. The growth of seedlings was very slow. The time to maturity was not well related to the maturity during the normal cropping season. Cooler temperatures prolonged time to maturity. All lines flowered but some did not set pods. The highest pod set was recorded in the early-maturity group. Grain yield and related attributes declined sharply when sowing was done in January as compared with the November sowing. The differences observed among selected cultivars and sowing dates were mainly due to variation in crop growth rate

Response of Cowpea Cultivars to Planting Pattern and Date of Sowing in Intercrops with Pearl Millet in Niger

A two-year study was conducted at two locations in Niger to compare the response of five cowpea cultivars to two planting patterns and two sowing dates relative to the sowing date of pearl millet. All the cowpea cultivars took less time to mature when planted three weeks after millet than when sown one week after. Early-maturing cowpea cultivars had the smallest yield, whereas the yield of the local indeterminate cultivar was nearly double that of the other cultivars at both dates of sowing. Early planting of cowpea significantly depressed millet yield, but when cowpea was planted late millet yields approached those of the sole crop. The local cultivar depressed millet yields more than the other cowpea cultivars. Planting pattern had no significant effect on the yield of either cowpea or millet. Cowpea yield was reduced by more than 50% by two weeks delay in sowing, confirming that the sowing date of cowpea relative to millet is a critical factor in the Sahelian pearl millet/cowpea intercropping system. There were marked differences in the effect of cowpea cultivar on millet yield but these differences were consistent over sowing date