Title : Physiological and biochemical evaluation of seed quality and vigor in selected landraces of bambara groundnut (Vigna subterranea L. Verdc.)
Abstract:
Bambara groundnut (BGT) is an underutilized African legume valued for its nutrient density and drought resilience, offering great potential for food security in Africa. Despite its adaptability, BGT cultivation largely depends on traditional landraces with poorly understood seed quality and vigor. This study assessed ten BGT landraces using physiological and biochemical markers to evaluate seed quality and vigor. Physiological tests included moisture content (AOAC standards), germination percentage (ISTA protocols), seedling vigor index, electrical conductivity for membrane integrity, and seed imbibition rate. Biochemical analyses measured proximate composition—ash, crude protein, fat, fiber, carbohydrates—and enzymatic activities of amylase, catalase, and peroxidase. Results revealed significant variation among landraces. Moisture content ranged from 13.40% in the Cream seed coat to 10.20% in dark speckled brown. Germination was highest in Cream seed coat (95%), followed by variegated Cream with Black Eye (93%) and Light Red (92%); dark speckled brown and deep purple scored lower (70% and 77%). Seedling vigor indices mirrored this, with creamy and variegated types exceeding 1900 and darker seed coats below 1200. Electrical conductivity indicated better membrane integrity in high performers (<15 µS cm?¹ g?¹) versus lower performers (>28 µS cm?¹ g?¹). Imbibition rates showed variegated landraces absorbed water faster (74–78%) compared to under 58% in others. Biochemical content varied, with protein ranging from 17.94% in deep purple to 23.50% in light speckled brown and carbohydrates between 52% and 61%. Enzyme activity peaked with catalase in Light Red (0.4231 U/g), peroxidase in Black seed coat (0.0981 U/g), and amylase in variegated Cream with Black Eye (3.58 mg/L) and dark speckled brown (3.56 mg/L). Overall, Cream seed coat, Cream with Black Eye, and Light Red displayed superior seed vigor, making them promising for breeding. The high-protein light speckled brown variety may help combat malnutrition. Elevated catalase and peroxidase activities suggest improved seed longevity and stress tolerance, essential for sustainable agriculture. This study highlights key factors influencing seed quality and vigor, providing valuable data for breeding, conservation, and food security in Africa.
