Abstract

The experiments were performed in the laboratories of the Mygenebank Complex in Malaysian Agricultural Research and Development Institute (MARDI) Serdang. Key lime (Citrus × aurantiifolia) Swingle germplasm planted in the field genebank suffers a huge loss due to witches-broom disease of Mexican lime (WBDL) associated with Candidatus Phytoplasma aurantifolia which has developed a need for a much simple and efficient method for the long-term conservation of this species. This study is aimed at observing 2 factors, namely the effect of desiccation on the survival of seed and excised embryonic axes after cryopreservation, and the effect of exposure time to plant vitrification solution 2 (PVS2) on the survival of cryopreserved embryonic axes. Citrus × aurantiifolia seeds can be desiccated below 10% MC as they survived with germination percentage ranged from 35% to 60% after cryopreservation and 50% to 90% without cryopreservation (control). The highest survival percentages of cryopreserved seeds were obtained (60%) after 3 and 4 days of desiccation, corresponding to seed moisture contents of 6% and 7.9%, respectively. For cryopreservation-dehydration of excised embryonic axes survival was observed in embryonic axes treated for 1 to 3 hours, presenting 60% to 67% survival while for cryopreservation-vitrification survival was only 10% to 13% after treated with PVS2 for 10–30 min. No embryonic axes survived with 0-hour desiccation or 0-minute exposure to PVS2 after cryopreservation. Comparing both cryopreservation methods used for excised embryonic axes, cryopreservation-dehydration indicated higher survival for Citrus species. However, refinement of the technique is needed before it can be used for this species.