Agro-morphological characterization of selected varieties of vegetable cowpea [Vigna unguiculata (L.) Walp.] in Burkina Faso

Vegetable Cowpea (Vigna unguiculata) is one of the neglected legumes in Burkina Faso, and as a result, its genetic diversity remains poorly known. The main aim of this study was to know its genetic variability through an agro-morphological characterization. Twenty vegetable cowpea varieties were evaluated at the Kamboinsé Environmental, Agricultural and Training Research Center following a three-replication Fischer block design under rainfed conditions. Fifteen quantitative and nine qualitative variables were collected and subjected to various statistical analyses. Analysis of variance was significant for the variables 50% flowering, vegetable cowpea date, number of pods obtained per plant, number of seeds per pod, fresh pod weight, fresh pod yield, pod length, plant height, seed length and chlorophyll content. Strong correlations were also reported between the various variables. The observed diversity is structured in three morphological groups viz., Group 1 consists of individuals with early flowering, high chlorophyll content and the number of pods obtained per plant. Group 2 brings together the varieties of average agronomic performance for pod length, the number of pods per plant, number of days at 95% maturity, fresh pod weight, yield of fresh pods and group 3 of varieties with long pods, early green date, high pod weight and good fresh pod yield. Among the tested varieties, the varieties IT83S-872 (30 pods), IT84S-2246 (27 pods), Baguette (25 pods), IT83S-818 (26 pods), and IT85F-2682 (24 pods) stood out for their high pod production. In addition, the varieties of vegetable cowpea baguette, baguette grimpant, Telma, and IT83S-911 showed the best performance in terms of early vegetable cowpea date stage, longest pods, highest pod weight and best yield of fresh pods. The high genetic variability level within the tested varieties could be exploited in future green cowpea breeding programmes

Genetic Analysis of Flower Bud Thrips Resistance (Megalurothrips sjostedti) in Cowpea (Vigna unguiculata [L.] Walp.) in Burkina Faso

Cowpea is an important grain legume in sub Saharan Africa where its protein rich grains are consumed. However, its production is hampered by some major constraints including flower bud thrips (Megalurothrips sjostedti) that can cause 60% to total crop yield loss. Therefore, the development of resistant varieties becomes necessary. Thus, the present study was designed to determine the inheritance and elucidate the genetic control of cowpea resistance to thrips. Generation mean analysis model was exploited to assess the mode of inheritance of the resistance to flower bud thrips in cowpea using six generations (P1, P2, F1, F2, BC1P1 and BC1P2) derived from cross of Komcallé and Sanzi. Parameters such as number of flowers abortion per plant, number of pods per plant, thrips damage, number of thrips per plant and 100 seeds weight were exploited for progenies evaluation. Generation mean analysis revealed the existence of additive (a), additive x dominance (ad) and dominance x dominance (dd) effects as the mode of gene action predominantly involved into cowpea for thrips resistance control. Number of effective factors for thrips damage control varied from 3 (number of aborted flowers per plant) to 6 (weight of 100 seeds). Estimated Broad and narrow sense heritabilities for flower bud thrips resistance were low indicating large effect of the environment on the trait

Field Assessment of Cowpea Genotypes for Drought Tolerance

Drought is one the most damageable constraints to crop production impacting negatively food security. The potential of cowpea to address food security is well established. However, drought due to limited rainfall is causing important yield losses. This study was conducted to assess cowpea genotypes for variability to drought tolerance at Saria Research Station, Burkina Faso, in 2012. Fifty cowpea genotypes were grown under drought stressed and non-stressed conditions. Plants grown under non-stressed conditions were watered regularly from sowing to maturity while those in the stressed conditions were watered from sowing to 50% flower bud initiation and thereafter, irrigation was withheld till harvest. Selection indices and principal component biplot were used to differentiate genotypes. A wide genotypic variability among the tested germplasm was found. In the Biplot displayed, genotypes were grouped into four categories according to their drought tolerance and yielding ability as indicated below: high yielding-drought tolerant (group A), high yielding-drought susceptible (group B), and low yielding-drought tolerant (group C), and low yielding-drought susceptible (group D). The stress tolerance index was the best criterion for assessing genotypes for variability to drought tolerance because it enabled the identification of high yielding and drought tolerant genotypes

Genetic Variability Induced by Gamma Radiation in Cowpea [(Vigna unguiculata L. (Walp)] in Burkina Faso

Cowpea is a good source of protein, minerals, and vitamins in most developing countries in Africa. However, this legume production is still limited by various biotic and abiotic constraints. Beyond these constraints, the pressure of conventional breeding methods on natural variability exhausted a narrow genetic base of cowpea. Therefore, it is important to explore other ways of broadening the genetic base of the crop. Gamma irradiation is an alternative to increase genetic variability and improve the genetic base of crops. This paper focuses on evaluating the level and structuring of agro-morphological variability induced by gamma radiation among M2 plants of cowpea genotype. So, Tiligre, Moussa local, and KVx396-4-5-2D genotypes were treated with 150 Gy of gamma rays. The M2 generation was then screened for genetic variability. Thus, 38 M1 plants (either 38 x 10 seeds) by genotypes are advanced to the M2 generation based on the plant by line method. Four (04) agro-morphological parameters were used to assess phenotypical variability. Analysis of variance showed a highly significant difference between the families of plants except those of KVx396-4-5-2D for the flowering time. The maximum variability was observed for the number of branches and the length of the peduncles with a very high coefficient of variation. A high broad-sense heritability was recorded for all measured traits (>75%) of Moussa Local; for plant height (81.1%) of KVx396-4-5-2D, for first flower date (80.2%), and peduncles length (78.6%) of Tiligre. Based on phenotypic characters, the principal component analysis (PCA) and the cluster analysis showed variation among genotypes irradiated, and they were grouped into four clusters in KVx-396-4-5-2D, six clusters in Moussa local and Tiligre populations. So, 150 Gy dose of γ-rays was effective to induce variability in morphological and phenological characters within cowpea genotypes

Genetic Diversity of Jatropha curcas in Burkina Faso Revealed by Microsatellite Markers

Jatropha curcas L. is a perennial oleaginous plant commonly used in tropical areas as a medicinal plant in the construction of defensive hedges against animals, and in the fight against water erosion. It produces oil which can be used as agrofuel or soap-making. Despite its potential, the species remain under-exploited and its genetic diversity is still not very well-known in Burkina Faso. This paper focuses on determining the level and structure of the genetic diversity of 50 accessions collected in three phytogeographical sectors of the country using 12 microsatellite markers. Resultsrevealed a total of 37 alleles in the studied population with an average of 3 alleles per locus, a number of 2.717 effective alleles, and a Shannon diversity index of 1.663. Mean observed heterozygosity and mean expected heterozygosity were 0.144 and 0.356, respectively. Accessions were structured into three genetic groups. The high genetic distance of 0.177 was observed between groups A and B, and a low genetic distance of 0.075 was observed between groups B and C. These preliminary results showed that microsatellites are promising tools that can be used for the characterization of J. curcas. They indicate that the population studied has a low genetic diversity, but it is sufficient to develop programs for conservation and sustainable development of the species

Redesigning crop varieties to win the race between climate change and food security

Climate change poses daunting challenges to agricultural production and food security. Rising temperatures, shifting weather patterns, and more frequent extreme events have already demonstrated their effects on local, regional, and global agricultural systems. Crop varieties that withstand climate-related stresses and are suitable for cultivation in innovative cropping systems will be crucial to maximize risk avoidance, productivity, and profitability under climate-changed environments. We surveyed 588 expert stakeholders to predict current and novel traits that may be essential for future pearl millet, sorghum, maize, groundnut, cowpea, and common bean varieties, particularly in sub-Saharan Africa. We then review the current progress and prospects for breeding three prioritized future-essential traits for each of these crops. Experts predict that most current breeding priorities will remain important, but that rates of genetic gain must increase to keep pace with climate challenges and consumer demands. Importantly, the predicted future-essential traits include innovative breeding targets that must also be prioritized; for example, (1) optimized rhizosphere microbiome, with benefits for P, N, and water use efficiency, (2) optimized performance across or in specific cropping systems, (3) lower nighttime respiration, (4) improved stover quality, and (5) increased early vigor. We further discuss cutting-edge tools and approaches to discover, validate, and incorporate novel genetic diversity from exotic germplasm into breeding populations with unprecedented precision, accuracy, and speed. We conclude that the greatest challenge to developing crop varieties to win the race between climate change and food security might be our innovativeness in defining and boldness to breed for the traits of tomorrow

Agromorphological Evaluation of 44 lines of Mung Bean (Vigna radiata (L.) Wilczek) Introduced in Burkina Faso

Mung bean (Vigna radiata L. Wilczek) is an important annual legume which is well suited to dry areas, like Burkina Faso where it is still an orphan legume. The present study was conducted to evaluate 44 mung bean genotypes introduced in Burkina Faso and to determine genetic diversity in this collection using both quantitative and qualitative traits. A field experiment was conducted in an augmented bloc design with three blocks and an extraearly maturing cowpea variety as check. Data were recorded on six (06) quantitative traits and seven (07) qualitative traits. For qualitative traits, diversity was revealed in four parameters including hypocotyl’s color, seed coat color, pods and stem pubescence. Significant genetic variability was revealed among genotypes for all the quantitative characters. Phenotypic coefficient of variation (PCV) was higher than Genotypic coefficient of variation (GCV) for all characters studied indicating the influence of environmental effect on the characters. The GCV and PCV estimates were high for number of pods per plant followed by plant height and hundred seeds weigh. The high heritability coupled with high genetic advanced as percent of mean observed for these traits suggest an important genetic gain in genetic improvement for these characters. The genetic diversity observed was grouped into five clusters. Mungbean lines were grouped into four clusters and the cowpea variety used as check crop in this trial was clustered apart. This genetic diversity, both qualitatively and quantitatively, will help enrich local biodiversity in terms of legumes in general and mung bean in particular and constitutes an important basis for a future mungbean breeding program

Assessment of Cowpea (Vigna unguiculata (L.) Walp.) Mutant Lines for Drought Tolerance

Cowpea provides the cheapest source of protein with an average range of protein content of 23–30%. However, cowpea growth, development, and yield are greatly affected by drought during flowering and pod filling in the sub-Sahelian areas. The best way to cope with this situation is to develop drought-tolerant cowpea varieties. The objective of this study was therefore to evaluate cowpea lines developed through mutagenesis using gamma radiation to assess their reaction under optimal and water-stressed conditions. The response of ten mutants-irradiated Moussa local was then evaluated in pots arranged in a split plot design in a screen house. Two conditions were applied with optimum and water-stressed conditions. The stress was applied for two weeks at flowering. Two cowpea varieties Gorom local (drought-tolerant) and Moussa local (susceptible) nonirradiated were used as checks. Thereafter, field trials under two different sowing dates were conducted to identify the best tolerant mutant line(s) using agromorphological and tolerance indicators. The results indicated that mutant lines (MoussaM51-4P10 and MoussaM43-20P14) exhibited better stress tolerance and produced higher yield under water stress conditions. Stress Tolerance Index (STI) was better to select cowpea mutant tolerant with higher yielding under moderate stress (SI = 35%). The study confirmed that water stress has a negative effect on cowpea seeds production and on leaf chlorophyll content. The high temperature during experiment increased water stress effect mainly on non-irradiated checks (Gorom local and Moussa local)

Selection and validation of marker set for selection of resistant varieties of cowpea to Cowpea Aphid-borne Mosaic Virus (CABMV) in Burkina Faso

Objective: This study aims to validate of marker set for selection of resistant varieties of Cowpea Aphid-borneMosaic Virus.Methodology and results: A molecular characterization of five genotypes using seventeen (17) SSR markers was carried out.Conclusion and application of results: This study make it possible to identify four (4) polymorphic microsatellite markers (VM30, VM33, VM68 and VM70), that is to say a rate of 23, 52% of polymorphism versus 76, 47% of monomorphism. Two of the polymorphic markers- VM68 and VM30 were submitted to the test of validation. At the end of this test, VM68 was codominant, because it makes it possible to distinguish the heterozygous individuals (F1, BC1 F1) from the homozygous individuals (F2) while the marker VM30 was dominating. The marker VM68 was validated and proposed in selection assisted by the markers of cowpea for resistance to CABMV.Keywords: cowpea, Cowpea Aphid-borne Mosaic Virus ((CABMV), Microsatellites, Validation, Burkina Fas

Assessment of Genetic Diversity of a Collection of Senna obtusifolia (L.) Irwin and Barneby Using SSRs Markers in Burkina Faso

Sennaobtusifolia (L.) is a plant in the genus Senna that contributes to improving nutritional quality, food security, and better health protection for rural populations. However, very few studies have been devoted to it in Burkina Faso. Consequently, its genetic diversity remains poorly known. Such neglect would lead to the erosion of its genetic resource. The general objective of this study is to contribute to a better knowledge of the genetic diversity of the species in order to be able to issue scientific bases for its conservation, valorization, and genetic improvement. Sixty (60) accessions of Senna obtusifolia were collected in the wild from five provinces of three climatic zones of Burkina Faso. Molecular characterization was carried out using 18 SSR markers. Fifteen were polymorphic microsatellite markers leading one hundred and one (101) alleles in total, with an average of seven (7) alleles per locus. The number of effective alleles was 2.33. Expected heterozygosity, Shannon diversity index, and polymorphism information content averaged 0.47, 1.05, and 0.47. Molecular characterization revealed the existence of genetic diversity within the collection. This diversity has been structured into three genetic groups. Genetic group 3 presents the highest genetic diversity parameters