Variation in Seeds Physical Traits of Bambara Groundnut (Vigna subterranea) Collected in Cameroon

Abstract
Vigna subterranea is a leguminous species which produces edible seeds (Bambara groundnut). Its seeds are included in the daily diet to compensate the lack of proteins in the food which occurs frequently in populations under the tropics. However information regarding the extent and pattern of variation in Bambara groundnut accessions in Cameroon is limited. The objective of this study was to estimate variation in seed physical traits of twelve Bambara accessions collected in different regions in Cameroon. Seeds of Twelve Bambara accessions were harvested in Janaury 2013 and kept for four months in the Laboratory of Botany and Plant Physiology of the University of Douala. Selection was based on their color. Individual seed length, width and thickness were measured as the physical traits. The seed characteristics were also calculated as the geometric mean diameter, sphericity, seed volume, seed surface area and the aspect ratio. Moisture content varied from 8.11 to 13.12%. Results revealed that there was a highly significant difference (p < 0.001) for all the studied physical traits and seed characteristics, indicating large variation in seed physical traits of Bambara groundnut in Cameroon. The mean length, width and thickness of Bambara seeds ranged from 9.68 to 11.75 mm; 8.73 to 10.46 mm and 8.12 to 10.30 mm, respectively. Large seeds had higher geometric mean diameters, volume and surface area. However, small seeds had higher sphericity and aspect ratio than large seeds. The seeds were irregular in shape and size, and highly spherical with high aspect ratio and will roll rather than slide. Thus variation between individuals has to be attributed to a high number of additive effects and parameters can be studied through selection as major candidates.