Diversity Studies in Vigna Species and Their Implications in Further Breeding

Abstract

Aims: To evaluate, identify and select superior genotypes with better agronomic traits with respect to insect resistance and yield components for the development of improved cowpea varieties. Study Design: The plants were raised using completely randomized design (CRD). Place and Duration of Study: Screen house of the Department of Botany, Obafemi Awolowo University, Ile-Ife, Nigeria, between between July 2017 and January 2018. Methodology: A total of 67 Vigna accessions consisting of 36 V. vexillata and 31 V. unguiculata species were evaluated and the quantitative and qualitative attributes of the various accessions studied were documented. The data obtained in the study were subjected to univariate analysis involving descriptive statistics, as well as multivariate analysis involving the General Linear Model (GLM) Analysis of Variance (ANOVA) and Principal Component Analysis (PCA). The differences among means of each variable were tested using the Duncan Multiple Range Test (DMRT) at ˂0.05 using System Analysis Software (SAS) version 9.13. Pearson Correlation Coefficient was also used to test the correlation among the quantitative attributes of the varieties studied. Results: The results of the investigation showed that there was significant variation in most of the quantitative attributes of the species studied though many of the qualitative vegetative attributes were considerably uniform. The Principal Component Analysis showed that some of the important traits that contributed significantly to the variation were number of days to seedling emergence, plant height, leaf length, leaf breadth, petiole length, pod length, pod breadth, seed length, seed breadth, number of seeds per pod and number of locules. Conclusion: From the findings obtained in this study, it could be concluded that the desirable traits of Tvnu1249 (V. vexillata) such as early maturity, and Tvnu72 (V. vexillata) with high percentage seed set and resistance to flower bud thrips could be transferred into Sanzi and Ifebrown (V. unguiculata varieties) with larger seed sizes and high percentage seed set through hybridization and other breeding techniques.