Agronomic evaluation of cowpea cultivars developed for the West African Savannas

Abstract

The goal of this research was to evaluate diverse cowpea genotypes developed over the past 4 decades in the Nigerian Sudan Savannas for their agronomic performance and to identify groups of cultivars with similar quantitative characters. Characterization would facilitate the efficient synthesis of breeding populations for further improvement of cowpea. Also superior genotypes with desirable characteristics could be identified and disseminated in the dry savannas of West Africa. Significant variations were observed in the agronomic characteristics of the cultivars in this study. Principal component analysis (PCA) and cluster analysis were performed on these genotypes and found that there were significant correlations among the variables measured. Modern cultivars outperformed the older ones and from the results of PCA, it was found that the most important variables for the classification of cowpea cultivars are high canopy, high seed weight, high total dry matter, high HI, and high grain and fodder yield. This suggests that these traits could be used in selection index for genetic improvement of cowpea. Cluster analysis resulted in 5 groups mostly corresponding to era of release except cluster I which contained cowpea cultivars from all eras. Two distinct groups in clusters IV and V were identified. Cultivars in cluster IV which were released in the 1990-2000 eras, had high grain and fodder yield. These cultivars could be evaluated on-farm for eventual release to farmers. They could also be used in breeding program for improvements in grain and fodder yield of cowpea. Cluster V contained two cultivars that distinctly had the highest fodder yield suggesting that they could be used to improve fodder yield of cowpea.

The evaluation of a southern African cowpea germplasm collection for seed yield and yield components

“…The current study has shown that seed yield is strongly positively correlated with number of pods, suggesting that when selection is applied for one of these traits, an indirect improvement could be observed in seed yield. The current study confirmed the previous reports for cowpea in South Africa (Gerrano et al., 2015; Gerrano, Jansen van Rensburg, & Kutu, 2019; Nkoana et al., 2019) and Nigeria (Kamara et al., 2017). Previous studies (Nkoana et al., 2019; Walle, Mekbib, Amsalu, & Gedil, 2019) showed that number of seeds per pod, number of pods per plant, and pod length had the strongest influence on seed yield.…”

Growth and yield of cowpea (Vigna unguiculata L.) cultivars under water Deficit at different growth stages

“…Cowpea (Vigna unguiculata L.) is grown in arid and semi-arid regions of the world where it is considered as the most drought-tolerant food legumes. The economic importance of cowpea are high protein content of the seeds (20% to 40%), N fixed biologically ranged from 73 to 354 kg N/ha per year, and the consumption of its foliage and fresh and dry grain (Kamara et al, 2017). It has been observed that there was a significant difference among cowpea genotypes with regard water deficit tolerance at the vegetative, flowering and pods filling stages (Ahmed and Suliman, 2010).…”

Assessing diversity in canopy architecture, photosynthesis, and water‐use efficiency in a cowpea magic population

“…We also found a positive correlation between the width of the canopy and iWUE canopy (Pearson's correlation coefficient = 0.56, p-value < .001; Supporting information 2), although this was found in the absence of drought stress. Kamara et al (2017) reported that increased cowpea total biomass contributed to greater seed yield, based on the positive correlations between canopy height and fodder yield with seed yield. Positive correlations between canopy height and plant biomass with canopy CO 2 assimilation were found in our study (Pearson's correlation coefficient = 0.48, pvalue < .001; Supporting information 2), which may indicate that improvement in canopy photosynthesis may contribute to increased seed yield.…”

“…In addition, inclusion of cowpea in the cropping system can contribute to restoration of soil fertility through the fixation of atmospheric nitrogen (Fatokun, Tarawali, Singh, Kormawa, & Tamò, 2002). Yet productivity of cowpea in Africa is low with average yields ranging 100–400 kg/ha (Kamara et al., 2017). For comparison with another dry bean, the average yield in the USA for soybean was 3,500 kg/ha in 2018 (USDA National Agricultural Statistics Service, 2019).…”