Genetic variability in cowpea ( Vigna unguiculata (L.) Walp.) genotypes (original) (raw)
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Cowpea (Vigna unguiculata ): Genetics, genomics and breeding
Plant Breeding
Cowpea, Vigna unguiculata (L.), is an important grain legume grown in the tropics where it constitutes a valuable source of protein in the diets of millions of people. Some abiotic and biotic stresses adversely affect its productivity. A review of the genetics, genomics and breeding of cowpea is presented in this article. Cowpea breeding programmes have studied intensively qualitative and quantitative genetics of the crop to better enhance its improvement. A number of initiatives including Tropical Legumes projects have contributed to the development of cowpea genomic resources. Recent progress in the development of consensus genetic map containing 37,372 SNPs mapped to 3,280 bins will strengthen cowpea trait discovery pipeline. Several informative markers associated with quantitative trait loci (QTL) related to desirable attributes of cowpea were generated. Cowpea genetic improvement activities aim at the development of drought tolerant, phosphorus use efficient, bacterial blight and virus resistant lines through exploiting available genetic resources as well as deployment of modern breeding tools that will enhance genetic gain when grown by sub-Saharan Africa farmers.
Determination of Some Agronomic Traits and Their Correlation with Yield Components in Cowpea
Selcuk Journal of Agricultural and Food Sciences
Food legumes play a significant and diverse role in the farming systems and the diets of poor people around the World (Stoilova, Pereira, Sousa and Carnide, 2005). Cowpea, Vigna unguiculata, is considered an essential grain legume adapted to sub-Saharan Africa (SSA) where it supplies to the nutrition, health, and income of rural and suburban inhabitants (Boukar et al., 2015). Cowpea is the most produced grain legume on the World after common bean and chickpea. Additionally, due to its high nutritional value, cowpea is one of the most important legumes for indigenous Africa (Agbicodo, Fatokun, Muranaka, Visser et al., 2009). Cowpea seed contains 24.8% protein, 1.9% lipid, 6.3% fiber, 63.6% carbohydrate, ash, riboflavin, carotene and vitamin B1 (Stancheva et al., 2016). Generally, the production and consumption of cowpea is high in the world, Although, it is lower than other grain legumes in the Turkish market. The cowpea production area was nearly 12.5 million
2017
Cowpea is a food and animal feed crop grown in the semi-arid tropics worldwide. Genetic diversity in crops allows the exploitation of different genotypes to breed new cultivars. Very little work has been undertaken in understanding and exploitation of the genetic variation that exists among cultivated varieties and local landraces of cowpea in South Africa. The objectives of the study were: 1) to assess the level of diversity among selected cowpea accessions using agro-morphological traits, 2) to assess the level of genetic diversity among selected cowpea accessions using single nucleotide polymorphisms (SNP) markers, and c) to determine the crude protein, iron and zinc contents in the grains of selected cowpea accessions grown under two planting dates at the Agricultural Research Council-Potchefstroom campus. Two planting dates were used, the first on 10 th December 2015 and the second on 10 th January 2016. Data were collected on 14 quantitative and qualitative traits. The analysis of variance for 10 quantitative traits revealed highly significant (P<0.001) differences among the accessions. The mean performance of accessions showed nine cowpea accessions that yielded higher than the two checks. Grain yield and some of the other agronomic and phenological traits showed a wide phenotypic variability. Among these were: days to 50% flowering, weight of mature pods, fodder yield, and phenotypic coefficient of variation (PCV) for number of main branches, pod length, pod width, number of seeds per pod and hundred seeds weight. Days to 50% flowering, weight of mature pods, grain yield and fodder yield had high genotypic coefficients of variation (GCV), and moderate to high heritability and genetic advance. This indicated that selection based on the mean would be successful in improving these traits. High heritability estimates along with high genetic advance implied additive gene action was more important in the inheritance of these traits. Grain yield was affected by planting date, where early planting date gave the highest mean value of 5725.9 kg /ha, while for the late planting date had a mean yield of 3756.9 kg/ha. Traits associations were estimated by simple correlation coefficients. Grain yield showed positive and significant correlation with weight of mature pods, fodder yield and number of seeds per pod. Selection for weight of mature pods, fodder yield and number of seeds per pod would, therefore, be essential for grain yield improvement in cowpea genotypes. Cluster analysis of phenotypic traits grouped the accessions into seven distinct groups and first six principal components showed 76.89% of total variability among genotypes. Number of main branches, days to 50% flowering, days to maturity and fodder yield contributed to PC1 and number of plants per plot, weight of mature pods, grain yield and fodder yield contributed largely to PC2. ACKNOWLEDGEMENT I would like to express my special thanks and appreciation to my supervisor Dr. Julia Sibiya for her close supervision, guidance, constructive criticism, support and hospitality including compilation of the final dissertation. I would also like to express my sincere gratitude to my cosupervisor, Dr. Alfred Odindo, for his guidance, encouragement, support and valuable comments during the entire period of study and proposal preparation. I would like to express my deepest gratitude to my co-supervisor Dr. Nemera Shargie for his unreserved, excellent expert co-supervision, vital theoretical and practical input, the many insightful comments and suggestions, consistent assistance, encouragement, all-round support and provision of materials without which the field work would not have been completed at ARC-Potchefstroom. Dr. Shargie generously supplied cowpea accessions used for this study and all necessary materials for research activities and for his hospitable and limitless help. He significantly contributed to making this study successful. I am also glad to express my sincere thanks to Dr. Abe Shegro Gerrano for his hospitable and limitless help to ensure the success of this research. I would like also to thank Dr.Amelework Beyene Assefa and Dr. Alina Mofokeng for their endurance, encouragement, general support and useful comments throughout my research. I would like to thank the Alliance for a Green Revolution in Africa (AGRA) for the financial support of my study through the University of KwaZulu-Natal South Africa. I would extend many thanks to our administrative officer Ms.Jayshree Singh for supplying necessary materials to run the research smoothly, administrative support and the logistics for the field trips to ensure the success of the study. I would like to express many thanks to my family for their eternally lovely encouragement, support, and advice throughout the entire study period. My very special thanks go to my brother Mr. Emmanuel Mrema for his cheerful encouragement, considerable help, support, advice and encouragement throughout my study period. I would also like to thank my fellow students, the MSc 2015 cohort, for their support and encouragement during my proposal write up and my dissertation write up. Finally, I would like to thank God, for his blessings to be able to successfully complete this research study.
Cowpea: a legume crop for a challenging environment
Journal of the science of food and agriculture, 2017
Cowpea is a grain legume native from Africa and is a primary source of protein for millions of people in sub-Saharan Africa and other parts of the developing world. The main important characteristics of this crop include a good protein quality with a high nutritional value, its nitrogen-fixing ability, and an ability to be more drought- and heat-tolerant than most of its legume relatives. In a research perspective, studies of cowpea are relatively scarce, despite its relevance to agriculture in the developing world and its resilience to stress. The present review provides an overview of different aspects of cowpea, with a special emphasis on the molecular markers for assessing genetic diversity, as well as on biochemical and transcriptomic data with respect to evaluating cowpea drought stress tolerance. The integration of both datasets will be useful for the improvement of cowpea because research on drought stress tolerance is of major interest for this crop in a challenging environ...
Genetic Diversity in Cowpea (Vigna unguiculata (L.) Walp) under Two Growing Conditions
Advances in Bioscience and Biotechnology, 2024
This study explores the use of genetic variability for advancing the genetic improvement of Cowpea (Vigna unguiculata (L.) Walp), particularly in response to insect infestation stress. Over a period spanning 2015 to 2017, forty accessions of cowpeas were evaluated to determine their variability under both insecticide spray and no insecticide spray conditions at the Teachings and Research Farms, Federal University of Agriculture, Abeokuta. The experimental design was a randomized complete block design in three replicates. The accessions were evaluated for plant height, leaf length, leaf width, number of days of 50% flowering, number of pods per plant, pod length, number of seeds per plant, 100-seed weight, and seed yield. Data collected were subjected to principal component and single linkage cluster analyses. Principal axis I (PCA1) accounted for 39% and 35% under insecticide spray and no insecticide spray respectively to the total variation in the accessions. Plant height with a factor score of 0.38, leaf length (0.41), number of leaves (0.37), and 100-seed, weight (0.30) was related to PCAI under insecticide spray while leaf width (0.32). Pod length (0.37) and number of seeds/plant (0.38) were significant to PCA1 under no insecticide spray. Notably, accessions such as SAMPEA6, SAMPEA10, IFE-Brown, and IFE-BPE exhibited consistent performance across both conditions, while others displayed condition-specific attributes. For instance, NGB1063, NGB1152, and NGB1093 demonstrated distinct traits under insecticide spray, while NGB1146 and NGB1124 exhibited notable characteristics under no insecticide spray conditions. Therefore, identifying these forty accessions with desirable traits hold promise for future genetic improvement efforts of cowpea cultivation in Nigeria and beyond.
Molecular Genetics and Breeding of Grain Legume Crops for the Semi-Arid Tropics
Genomics-Assisted Crop Improvement, 2007
Grain legumes are important crops for providing key components in the diets of resource-poor people of the semi-arid tropic (SAT) regions of the world. Although there are several grain legume crops grown in SAT, the present chapter deals with three important legumes i.e. groundnut or peanut (Arachis hypogaea), chickpea (Cicer arietinum) and pigeonpea (Cajanus cajan). Production of these legume crops are challenged by serious abiotic stresses e.g. drought, salinity as well as several fungal, viral and nematode diseases. To tackle these constraints through molecular breeding, some efforts have been initiated to develop genomic resources e.g. molecular markers, molecular genetic maps, expressed sequence tags (ESTs), macro-/micro-arrays, bacterial artificial chromosomes (BACs), etc. These genomic resources together with recently developed genetic and genomics strategies e.g. functional molecular markers, linkage-disequilibrium (LD) based association mapping, functional and comparative genomics offer the possibility of accelerating molecular breeding for abiotic and biotic stress tolerances in the legume crops. However, low level of polymorphism present in the cultivated genepools of these legume crops, imprecise phenotyping of the germplasm and the higher costs of development and application of genomic tools are critical factors in utilizing genomics in breeding of these legume crops Buhariwalla HK, Jayashree B, Eshwar K, Crouch JH ESTs from chickpea roots with putative roles in drought tolerance. BMC Plant Biol. 5: 16 Burns MJ, Edwards KJ, Newbury HJ, Ford-Lloyd BV, Baggott CD (2001) Development of simple sequence repeat (SSR) markers for the assessment of gene flow and genetic diversity in pigeonpea (Cajanus cajan). Mol. Ecol. Notes 1: 283-285 Burow MD, Simpson CE, Paterson AH, Starr JL(1996) Identification of peanut (Arachis hypogaea L.) RAPD markers diagnostic of root-knot nematode (Meloidogyne arenaria (Neal) Chitwood) resistance. Mol. Breed. 2: 369-379 Burow MD, Simpson CE, Starr JL, Paterson AH (2001) Transmission genetics of chromatin from a synthetic amphidiploid to cultivated peanut (Arachis hypogaea L.): broadening the gene pool of a monophyletic polyploid species. Genetics 159: 823-837 Burow MD, Starr JL, Simpson CE, Paterson AH (1996) Identification of RAPD markers in peanut (Arachis hypogaeaL.) associated with root-knot nematode resistance derived from A. cardenasii. Mapping genes for double podding and other morphological traits in chickpea. Euphytica 125: 285-292 Cho S, Chen W, Muehlbauer FJ (2004) Pathotype-specific genetic factors in chickpea (Cicer arietinum L.) for quantitative resistance to ascochyta blight. Theor Appl Genet 109: 733-739
Journal of Plant breeding and Crop Science, 2018
Ethiopia is claimed to be a center of diversity for cowpea production. The crop is the most drought tolerant and could help the country overcome the recurrent drought problem; however, the yield is very low due to lack of effort to develop varieties. This research was conducted to evaluate the stability of cowpea genotypes and to estimate the magnitude of genotypes by environment interaction (GEI) effect on grain yield. Sixteen cowpea genotypes were tested at seven environments in an experiment laid out in a 4 × 4 triple lattice design during 2016/17 cropping season. The combined analysis of variance over environments showed significant differences among genotypes and environments, along with significant effect of GEI on grain yield, days to flowering, days to maturity, plant height and pods per plants. Analysis of variance for grain yield from AMMI model indicated the contribution of genotype and environment, with GEI accounting for about 63.3, 5.3 and 29.7% of the total sum of squares, respectively. The result indicated that environments contributed much to the observed variations suggesting the need to test cowpea genotypes in diverse environments. Considering all stability parmeters, viz; deviation from regression (S 2 di), coefficient of regression (bi) from ER's model, IPCA1, IPCA2 and AMMI stability value (ASV) from AMMI model, GGE biplot and variety TVU was identified as the most stable with mean yield above the mean grain yield of genotypes. Two genotypes: IT-99K-1060a (1398.8 kg/ha) and 86D-378 (1377.1 kg/ha) had first and second highest yield, identified as responsive to both environments but more to favorable environments suggesting the need to further test and develop as varieties. The other two genotypes: 95K-1095-4A and 93K-619-1, identified as unstable and highly responsive to environments suggested to consider the genotypes as candidate varieties where they performed best. Melkassa, Sekota and Jinka were identified as more descrimnating environments, whereas Arbaminch and Kobo were ideal for selecting superior genotypes; however, Babile and Meisso were non descrimnating environments.
Scientia Horticulturae, 2017
Cowpea (Vigna unguiculata (L.) Walp.) is widely grown by subsistence farmers in West and East Africa where its grain and leaves are sources of highly valuable food, due to their high contents of proteins, minerals and vitamins. Therefore, cowpea could play a significant role in mitigating malnutrition such as micronutrient deficiencies. The objectives of this study were to evaluate the performance in agronomic traits of cowpea entries (released and farmers' cultivars, and gene bank accessions) from different sources, and to assess the extent of genetic diversity in this material to provide basic information for its use in breeding programs. A total of 15 entries were evaluated. All entries were morphologically uniform, except the farmers' local cultivars. Fresh leaf yield varied from 34.6 to 52.8 g per plant and days to 50% flowering from 64 to 82 days. Hundred seed weight ranged from 7.67 to 15.12 g. On average, the number of pods ranged from 4.8 to 15.6 pods per plant. No correlation between fresh leaf yield and other traits was detected, whereas the number of pods per plant and the hundred seed weight were negatively correlated. Genetic diversity was assessed on five genotypes per entry using 544 Amplified Fragment Length Polymorphism (AFLP) and 18 microsatellite markers. Genetic distances calculated using the Jaccard algorithm ranged from 0.002 to 0.193 among genotypes of the same entry and from 0.098 to 0.301 for genotypes from different entries. A principle coordinate analysis separated four entries from the rest. Although the consensus tree based on Neighbor Joining trees was unable to resolve the whole cluster, an assignment of most of the entries into entry-specific clades was possible.