Performance of Micropropagated and Conventional Passion Fruit (Passiflora edulis Sims.) Varieties in Three Contrasting Agroecological Zones

Abstract

Diseased propagules prevent adequate production of passion fruits (Passiflora edulis Sims.) in Kenya. Commercial micropropagation of P. edulis is not practiced in Kenya, and its implications are not known. The objective of the current study was to determine the effect of site and planting material on growth and yield of passion fruits. The experimental layout used was split plots in randomised complete block design. Contrasting sites assigned to main plots were Lare, Njoro and Molo. Tested planting materials assigned to subplots were yellow conventional, yellow tissue-cultured, yellow conventional grafted, yellow tissue-cultured grafted, purple conventional, purple tissue-cultured. Each treatment had 10 plants, replicated four times in each site. Plant growth and yield were assessed for over one year. Generally, plant performance depended on the site and planting material that significantly (P≤0.05) interacted. Growth of planting materials was more vigorous in Lare followed by Njoro and lastly Molo. Yellow passion fruits were severely stunted in Molo followed by Njoro, but grew vigorously in Lare. Non-grafted yellow passion fruits failed to set flowers and fruits during the first year. Highest yielding plants varied with site. Interaction of planting material and site significantly (P≤0.05) affected total soluble solids only. Most micropropagated plants were slightly more vigourous than corresponding conventional materials in each site. Thus variety, soils, climate and pests also influenced performance. Micropropagation proved effective for rapid multiplication of passion fruit plants, but the type of material to plant successfully will vary depending on agroecological zones. Pilot tests ought to be conducted in each site before implementing large scale planting. Organizations with tissue culture laboratories are recommended to adopt this method to multiply passion fruit varieties for growers.