In vitro regeneration of Ugandan passion fruit cultivars from leaf discs.

OBJECTIVE

Passion fruit improvement efforts by conventional breeding have had limited success calling for research into alternative approaches such as tissue culture and genetic engineering. An efficient and reproducible regeneration system is a prerequisite for successful genetic engineering. Currently, there is no reliable regeneration system for Uganda's passion fruit varieties owing to the high heterogeneity of the Passiflora genus. Therefore, this study aimed at establishing an efficient and reproducible regeneration system for Uganda's Passiflora edulis f. flavicarpa (yellow passion fruit) and Passiflora edulis f. edulis (purple passion fruit) for routine utilization with an ultimate goal of improving its agronomic value.

RESULTS

The study successfully induced shoots by both direct and indirect organogenesis for the yellow passion fruit variety. Highest shoot induction frequency (14.85%) was achieved on 8.9 μM BAP while 7.9 μM BAP did not initiate any shoots. Optimal shoot elongation and rooting was achieved on 0.44 μM BAP and 5.37 µM α-naphthaleneacetic (NAA) respectively. Rooted yellow passion fruit plantlets were successfully weaned with over 65% survival rates. It took approximately 6 months to produce a weaned healthy passion fruit plant. The purple passion fruit variety proved to be recalcitrant to tissue culture with no successful shoot or callus induction.