Slow post-hydration drying improves initial quality but reduces longevity of primed bitter gourd seeds

Many environmental factors are known to affect the success of priming, post-hydration drying being critical. Accumulated evidence shows that priming improves the quality of bitter gourd (Momordica charantia L.) seeds. However, the effect of post-hydration drying on the their longevity remains unclear. This study evaluated the effects of post-hydration drying speed on the emergence performance and anti-oxidative activities of primed bitter gourd seeds stored for 48 weeks. Results indicated that priming improved emergence percentage, mean emergence time and seedling growth of treated seeds. Primed seeds also showed lower peroxidation, as indicated by the accumulation of malondialdehyde (MDA) and total peroxide, and higher total anti-oxidative activities (TAA) than non-primed seeds. The seeds receiving slow post-hydration drying treatment exhibited faster emergence and better seedling growth than the seeds receiving fast post-hydration drying treatment and the non-primed control. However, the longevity of slow-dried seeds decreased considerably during 48 weeks of storage as compared to that of non-primed and fast-dried seeds. Fast drying treatment maintained the longevity of primed seeds for up to 24 weeks as compared with non-primed control or slow-drying seeds. Improved longevity was due in part to enhanced TAA that minimized the accumulation of MDA and total peroxide during storage.