Estimates of genetic divergence in cowpea by multivariate analysis in different environments

Abstract

Cowpea is a legume of great importance in the Brazilian nutrition, mainly in the Northeast region. Despite the low yield of Brazilian cowpea, the species presents a genetic potential to be explored. Thus, this work aimed to characterize the genetic diversity of cowpea genotypes by agronomic traits and select genotypes for possible crosses by multivariate analysis. Four value for cultivation and use tests were carried out with cowpea genotypes in 2005 and 2006, in the municipalities of Aquidauana, Chapadão do Sul, and Dourados, in the state of Mato Grosso do Sul. The experimental design was a complete randomized block with 20 genotypes and four replications. The evaluated traits were value for cultivation, plant lodging, pod length, grain weight of five pods, number of grains per pod, pod weight, severity of powdery mildew, and grain yield. To estimate the genetic diversity among the genotypes, the optimization methods of Tocher and UPGMA were used. The generalized distance of Mahalanobis was used as a dissimilarity measure. The clustering methods revealed genetic variability among the cowpea genotypes evaluated. The methods used formed a different number of groups for each environment. Genotypes TE97-309G-24, MNC99-542F-5, BRS Paraguaçu, BRS Paraguaçu, BR 17-Gurguéia, and CNC x 409-11F-P2 can be used to obtain promising combinations and high genetic variability.

Genetic Diversity of Cowpea Genotypes Grown in the Brazilian Cerrado

“…The effect of genotypes (G) was significant for all characters evaluated (Supplemental Table 1). Similar results were obtained in other research with cowpea in Brazil (Abreu et al, 2019;Ribeiro et al, 2019;Santos et al, 2014Santos et al, , 2019Torres et al, 2016). Crop season (CS) effect was not significant only for LOD.…”

“…Groups II, III, IV, V, VI, and VII allocated genotypes with the lowest GY averages. Increasing GY is the main objective of cowpea breeding programs (Guerra et al, 2017;Passos et al, 2007;Ribeiro et al, 2019).…”

“…The first step for developing genotypes with greater yields is the choice of parents, which need to have genetic divergence between them and alleles favorable for better agronomic traits of commercial interest. Therefore, genetic diversity studies are necessary to assist breeders in determining the most promising hybrid combinations (Ribeiro et al, 2019;Santos et al, 2014).…”

Multivariate Analysis of Genetic Diversity Among Okra (Abelmoschus spp.) Cultivars Grown in Côte d’Ivoire Based on Agro-morphological Traits

“…The use of multivariate techniques is an important strategy for estimating genetic diversity (Tadesse et al 2018). According to Parvin et al (2019) and Teodoro et al (2019) more than one multivariate technique is required for a better diversity analysis, since each one has its own particularity. In the present investigation, two multivariate methods were used: Principal Component Analysis (PCA) and Cluster Analysis (CA).…”

“…Therefore, in this study, the important genetic distance among the clusters suggests the possibility of improving the crop through the use of cultivars grouped in distant clusters as parents for hybridization. This fact would result in progenies with a broad genetic base and a higher probability of obtaining new genetic combinations with useful characteristics in segregating generations (Teodoro et al 2019). In addition to the genetic distance, the selection of the parents should also consider the special advantage of each cluster and each genotype within a cluster depending on the objective of hybridization (Gangopadhyay et al 2017).…”