Effects of seed maturity level, desiccation, packaging and storage temperature on seed quality of spiderplant (Cleome gynandra L.)

Abstract

Two experiments were conducted to determine the critical moisture content and the best storage conditions for spiderplant seeds with a view to addressing the poor seed quality and promote conservation of this plant genetic resource. In experiment one, seeds harvested at three pod maturity stages; yellow, yellow-green and green were dried above silica gel to percentage moisture contents of 20, 10, 5 and 2. For each maturity stage, viability and vigour tests were conducted. Percent germination and vigour increased with seed maturity. Prior to storage, initial germination for green, yellow-green and yellow pod maturity stages was 0.75%, 12% and 14.5% respectively. Green pod maturity stage had the least vigour as indicated by the mean germination time and electrical conductivity values of 4.18days and 420.77 Scm-1g-1 respectively. Yellow pod maturity stage had the highest vigour of 2.00 days mean germination time and electrical conductivity of 20.51 Scm-1g-1. Yellow-green pod maturity stage was intermediate with 2.02days mean germination time and 22.61 Scm-1g-1 of electrical conductivity. Germination of seeds from yellow and yellow-green pods increased with reduction in moisture content while that of green pods decreased. Based on this study, the critical moisture content for spiderplant seeds could be between 5% and 3%. Mature seeds that had been dried to the four moisture levels in experiment one were sealed in aluminum foil and polythene packets and stored at ambient temperatures (10oC - 26oC), 5oC and -20oC for six months. After six months storage period, viability and vigour tests were conducted. Seed stored for six months at 5% moisture content and minus 20oC recorded the highest seed quality. There were no significant differences (P>0.05) between seeds packaged in aluminium foil and polythene packets. In conclusion, spiderplant seed should be harvested at yellow pod maturity stage, dried to 5% moisture content, and stored at minus 20oC.