Segregation of Genes Controlling Seed Coat Color in Cowpea (Vigna Unguiculata [L] Walp)

Abstract

Cowpea coat color is a consumer-related trait that determines consumer preference and acceptability of the commodity in the market. Understanding the mode of inheritance of seed coat color will assist in choosing appropriate breeding technique in developing desirable cowpea varieties. This study was conducted to confirm the specific mode of inheritance of seed coat color in cowpea. Three bi-parental crosses using five different varieties of cowpea with contrasting seed coat colors were carried out to obtain F₁ seeds at the Greenhouse, Faculty of Agriculture, Obafemi Awolowo University, Ile – Ife, Nigeria. The F₁s were advanced to obtain F₂ segregating populations which were evaluated by visual observation and the seeds were categorized into different distinct groups. The observed seeds of the F₂ population of all the three crosses deviated extremely from Mendelian monogenic inheritance ratio in different degrees. TVu4669 × TVu43 segregated into two color groups resulting in brown mottled (15.4 %) and black mottled (84.6 %). Ife Brown  × TVnu699 segregated transgressively into five distinct groups of colors giving rise to brown (51.4%), black (23.7%), grey (14.8%), red (5.3%) and speckled (4.8% ); while Ife Brown × TVu2723 segregated into three color groups involving mottled black (4.3%), black (85.1%) and speckle (10.6%) coat colors. It could be inferred that more than one gene controls the inheritance of the seed coat color in cowpea, which implies that the trait is polygenic. It is recommended that molecular genetics’ techniques be explored in order to have better understanding of the mode of inheritance of seed coat color in cowpea.