Effect of moisture content and temperature on viability, vigour and longevity of cordia sinensis lam. seeds in storage

Cordia sinensis Lam. in the family Boraginaceae is a popular indigenous multipurpose tree species valued for fodder, fruit, structural timber and fuel wood. It is widely distributed in the arid and semi-arid lands (ASALs) of Kenya. Production of seedlings is through seeds. There are challenges acquiring viable and vigorous Cordia sinensis seeds for raising planting materials due to difficulties in post-harvest storage. In spite of the tree’s exceptional multipurpose qualities and ability to grow in ASALs, very little effort has been put in improving the post-harvest storage of the seeds. Changes occurring in all seed during aging are significant as far as seed quality and longevity are concerned and are a consequence of the effects of different storage conditions and C. Sinensis seeds are not exceptional. Information on their seeds viabilty and vigour loss in storage is scanty and unrelable. It is against this background that this study investigated the effects of different moisture content (MC) and temperature regimes on viability and vigour loss of Cordia sinensis seeds in storage. The broad objectives of this study were to determine the rate of loss of viability, vigour and lonevity of Cordia sinensis seeds under varying moisture contents and temperatures regimes. The experiment combined five moisture contents (MC) (6%, 8%, 10%, 12% and 18%) and four storage temperature regimes (60C, 150C, 250C, and 350C) for a period of 150 days and stored seeds retrieved at interval of 30 days for viability, vigour and longevity tests. Data generated were subjected to analysis of variance (ANOVA) using general statistics (GenSTAT; 16:2013). The results revealed that C. sinensis seeds with lower moisture content of 6% stored across 60C, 150C, 250C and 350C temperature regimes maintained significantly higher viability, vigour and highest P50 (measure of longevity in days) compared to other seeds with higher moisture content stored across all temperatures regimes. However, seeds from both Marigat and Lodwar with highest MC (18%) stored across respective five-temperature regimes maintained lowest seed viability, vigour and lowest longevity (P50) as storage period progressed to 150 days. There was positive correlation between seed viabilty and seed vigour when both temperaures and MC decreased such that both viabilty and vigours increased. This suggests that decrease in storage temperatures and seed MC increased seed longevity, seed vigour and seed viability. Increases in seed viability, vigour and longevity, in storage was in the order of 6%>8%>10%>12%>18% MC and 60C>150C>250C>350 temperature over time. The study concluded that Cordia sinensis seeds stores best at 6% moisture contents at lower storage temperarure of 60C, again lower seed moiture contents of 6% stored relatively better compared to seed with 8%, 10%, 12% and 18% across all storage temperature of 60C, 150C, 250C, and 350C. Thus recommends to seed handlers to dry the Cordia sinensis seeds to 6% for higher longevity, vigour and viability.