Ultra dry seed storage- a cost effective method for conservation of germplasm and commercial seeds of papaya

Abstract

Studies on ultra dry seed storage were undertaken in papaya to find out its effect on seed longevity under ambient and controlled temperatures. Fresh seeds of cvs. Arka Prabhath and Arka Surya dried to 4.1% and 4.2% moisture content, respectively could maintain initial viability and vigour up to 42 months and 36 months in cv. Arka Prabhath and cv. Arka Surya respectively, under ambient temperature. However, ultra dry seeds of Sunrise Solo with 3.6% m.c. showed reduced germination immediately after drying than seeds with 8% m.c. indicating reduction in m.c. below 4% may be harmful. Whereas seeds with moisture content of 7.5-8.1% showed decline in seed viability and vigour after 18 months of storage under ambient temperature and rapid decline was noticed after 30 months of storage, reaching 50% viability in cv. Arka Prabhath, 17% in cv. Arka Surya and 0% in Sunrise Solo at 42 months. At 15°C seeds with 7-8% moisture content showed no decline in viability and vigour after 42 months of storage in Arka Prabhath and Arka Surya and upto 66 months in Sunrise Solo. Whereas, ultra dry seeds of Arka Prabhath and Arka Surya could maintain more than 85% germination up to 72 months. Similarly, ultra dry seeds of Sunrise Solo maintained its germination and vigour up to 72 months. Similar trend was observed for field emergence.