Effect of immersion time in PVS2 and mesotesta removing on cryopreservation of papaya (Carica papaya L. ‘Sukma’) seeds

Cryopreservation of papaya seeds is recommended because these seeds, although tolerant to desiccation, cannot be stored for long-term at the low temperatures of standard seed banks (i.e., seeds are classified as "intermediate"). Cryopreservation is a method of germplasm conservation using liquid nitrogen. This study aimed to compare the viability of seeds with and without mesotesta after being stored by cryopreservation. This research was conducted at the Seed Storage Laboratory of Department of Agronomy and Horticulture, Faculty of Agriculture, Bogor Agricultural University, from August to December 2015. The experiment was designed as a factorial in completely randomized design with two factors. The first factor was the immersion duration in plant vitrification solution 2 (PVS2) with five incubation times, i.e., 0, 15, 30, 45, and 60 min. The second factor was seed condition either with or without mesotesta. The results showed that seeds without mesotesta tend to give the best germination rate, and the best immersion duration in cryoprotectants was 30 min, with the results of the germination rate and growth rate being 48.0 and 2.9%, respectively.