Evaluation of grain yield and canning quality traits of cowpea genotypes

Thesis (M. Sc. (Agronomy)) -- University of Limpopo, 2021

Cowpea (Vigna unguiculata (L.) Walp) is an important annual leguminous crop grown in arid and semi-arid areas in Sub Saharan Africa. Most of the cowpea production in South Africa is mainly used for domestic consumption and, as seed for planting and little gets to be used in food processing, thus, there is a need to expand the utilization of cowpea through food processing. This study aimed to evaluate cowpea genotypes for phenotypic and canning quality traits. Field experiments were conducted at two locations in Limpopo Province, namely Syferkuil Agricultural Experimental Farm and Ga-Molepo village during the 2017/2018 growing season. The field experiment was comprised of 100 cowpea genotypes laid out in an Alpha Lattice Design replicated twice. Cowpea canning analysis was done using tomato puree following ARC-GC in-house method at the Agricultural Research Council-Grain Crops in Potchefstroom, North West Province of South Africa. Collected data on yield was analysed using Genstat 18th edition and XLSTAT 2021.1.1.1081 software for canning quality data. The results revealed significant differences among the cowpea genotypes based on the number of seeds per pod and 100 seed weight for Syferkuil. Significant differences were also observed among the studied genotypes for 100 seed weight at Ga-Molepo. The highest yield recorded across locations was for genotypes RV 555 (875.4 kg/ha), RV 207 (756,3 kg/ha), RV 439 (694.6 kg/ha) and RV 554 (682.3 kg/ha) respectively. The number of pods per plant recorded a high positive association with pod number per plant and number of seeds per pod. Grain yield of RV 558, RV 556, RV 207, RV 439 and RV 553 was high at Syferkuil and at Ga-Molepo RV 353, RV 194, IT99K-494-6, RV 341 and RV 202 recorded the highest yield. The Principal Component Analysis (PCA) revealed the three most important PCs contributing to a total variation of 76.71%. PC1, PC2, and PC3 contributed 51.01, 13.97 and 11.73%, respectively. For canning ability, out of 79 cowpea canned genotypes, only 11 genotypes were spoiled and had a bad odour. About 68 genotypes were suitable for canning including genotypes that had an excellent appearance without cracks or loose skins and even colour. Furthermore, there was vast variability among the genotypes based on yield and yield components as well as canning quality traits. Genotypes with high grain yield and had canning ability are recommended xi for canning. Data produced from this study will add useful information to the database of the characteristics of these cowpea genotypes.