IN VITRO PROPAGATION OF THREE COMMERCIAL PASSIONFRUIT VARIETIES IN UGANDA

Small purple (Passiflora edulis f. edulis) and yellow (P. edulis f. flavicarpa) and KPF 4 (a cross between the two varieties) passionfruit varieties are of high economic importance in Uganda. Production of passionfruit is greatly constrained by viral diseases, leading to significant yield losses. This is aggravated by lack of adequate quantities of clean planting material. In vitro propagation through nodal sections is one way that has been successful in rapidly producing planting materials of vegetatively propagated crops that are clean and true-to-type. This study was aimed at obtaining optimum in vitro growth conditions for rapid micropropagation of the commercial passionfruit varieties in Uganda. Surface sterilised nodal sections from two month old plants were used as explants. For shoot regeneration, explants were cultured on Murashige and Skoog (MS) media, supplemented with varying concentrations of 6-Benzylaminopurine (BAP), either singly or in combination with Kinetin (KIN). Rooting MS media was fortified with varying concentrations of 1-Naphthalene acetic acid (NAA), either singly or in combination with BAP. MS medium supplemented with a combination of 2 mg l^-1 BAP and 0.5 mg l^-1 KIN, optimally supported shoot regeneration of the three passionfruit varieties. The average number of shoots and shoot height were 3.3 and 3.1 cm, respectively. Optimal root development was observed on MS media containing 3 mg l^-1 NAA, with a mean number of 5.5 leaves and a length of 2.4 cm. The rooted in vitro plantlets were successfully established in a potting mixture containing loam soil and manure in ratio of 1:1.