Cowpea seed coat chemical analysis in relation to storage seed quality

Abstract

Field emergence of stored cowpea seeds in the tropical environment is a major limitation to its production, particularly in cultivars with unpigmented seed coats. To determine the storage potential of cowpea, seeds of five cultivars comprising two pigmented and three unpigmented ones were subjected to controlled deterioration (20% m. c./40°C) for four days, accelerated ageing (40°C/100% r. h.) for six days and prolonged simulated tropical storage conditions (30°C/75.5% r. h.) for six months. They were tested for germination, electrical conductivity of seed leachate, vital staining of embryo, and the rate of water uptake. It was found that though all five cultivars suffered deterioration in storage, the pigmented cultivars deteriorated less as revealed by better germination, lower electrical conductivity of seed leachate, and vital staining of embryo. It was found that the pigmented seed coats contained higher amounts of chemical compounds which was associated with germination after storage. The relationship between seed quality parameters and the seed coat chemical compounds were highly significant, suggesting that the concentrations of the compounds have significant influence on the physiological behaviour of cowpea seeds during storage.



Key Words: Accelerated ageing, electrical conductivity, controlled deterioration, seed leachate


(African Crop Science Journal 8(3) 2000: 283-294)