Survival of chickpea, sesame, niger, castor and safflower seeds stored at low and ultra low moisture contents for 16-18 years

Abstract

The effect of low and ultra-low moisture contents and temperature on the survival of seeds in storage was studied for five crop species: chickpea, sesame, safflower, castor and niger. Seeds dried to moisture content levels recommended for genebanks and below (1.7-2.3%) were hermetically sealed and stored at ambient temperature, 4 and -18°C. Storage performance of seeds stored for 16-18 years was monitored by means of germination tests. Moisture, temperature and their interaction had significant effects on germination for all crops. At ambient temperature and 4°C, germination after 16-18 years was maximum at the lowest moisture contents of 2.3, 1.7, 2.0, 2.0 and 2.0%, which at ambient temperature was 94% (niger), 88% (safflower and chickpea), 86% (sesame) and 36% (castor). Seeds stored at 4.0, 3.8, 5.0, 4.5 and 3.2% for niger, safflower, chickpea, sesame and castor were dead at 13, 15, 16, 8 and 10 years, respectively. At -18°C, no significant decline in germination was recorded in seeds below 6% moisture content except in sesame. Storage of chickpea, sesame, niger, castor and safflower for 16-18 years at moisture contents below those recommended improved their survival at ambient temperature. In these species, drying below the recommended seed moisture content of 3% has considerable potential for medium-term storage under ambient and cooler temperatures.