Priming (controlled hydration followed by drying) has been shown to decrease seed storage life in some species The germinablity of primed (0.3 M KNO3, 6 d, 25°C) and unprimed muskmelon (Cucumis melo L., cv. PMR 45) seeds were compared after storage for 9 yrs at less than 20°C and 6% moisture content (MC) (dwt basis). Germination performance was compared at 30°C in water and polyethylene glycol solutions of -0.2, -0.4, -0.6, -0.8, and -1.0 MPa water potential or in water at 15, 20, and 25°C. Seeds were also germinated in field soils at 17, 19, and 21% (dwt. basis) MC in a greenhouse, Some seeds were subjected to controlled deterioration at 20% MC and 45°C for 72 hrs prior to testing. The germination percentage and rate of stored, primed seeds at 30°C and all water potentials was less than stored, unprimed seeds. At 30°C, stored, unprimed seeds germinated more rapidly and to higher percentages at -0.2 MPa than in water, while germination percentages and rates of stored, primed seeds were essentially the same. At 15, 24, and 25°C, stored, primed seeds outperformed unprimed seeds in all germination tests. In saturated soils at 21% MC, there was no germination of either stored, primed or unprimed seed. At 17% soil MC, stored, primed seeds germinated 73% compared to only 56% for unprimed seeds. The enhancement due to priming was retained after 9 yrs of storage at germination temperatures <30°C. At higher temperatures, the germination of unprimed seeds was superior to primed.
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