Flowering and Fruiting of Yellow Passion Fruit (Passiflora Edulis, Var F. Flavicarpa. Deg) as Influenced by Different Fertilizer Applications in Kiambu and Embu Counties, Kenya

Abstract

Yellow passion fruit (Passiflora edulis f. flavicarpa Deg.) is increasingly becoming an important fruit crop in Kenya and especially in Embu County due to its apparent adaptation to the hot arid conditions. The main objective of this study was to assess flower induction and fruit formation of yellow passion under varying fertilizer treatments. Sixty four plants belonging to KPF4 variety were grown in two sites at Kenyatta University (KU) Farm and at a selected farmer’s orchard in Embu. The experiment was laid out in a Factorial Complete Randomized Block Design with planting and top dressing fertilizers as the main factors. The planting fertilizers were Farmyard manure and Diammonium phosphate (DAP) while the top dressing was Calcium ammonium nitrate (CAN) and Nitrabor. The treatments included 100g DAP+20kg Manure+50g Nitrabor; 100g DAP+10kg Manure+50g Nitrabor; 100g DAP+50gCAN; 100g DAP+50gNitrabor; 10kg Manure+50g CAN; 10kg Manure+50g Nitrabor; 20kg Manure+50gCAN; 20kg Manure+50g Nitrabor; 50g DAP+10kg Manure+50g CAN, 50g DAP+50g CAN, 50g DAP+50g Nitrabor and Control (no fertilizer). Data recording begun at the onset of the first flower bud and the number of unopened flower buds, open flowers and young unripe fruits was recorded on a weekly basis. Results indicate that there were significant differences (≤0.05) among the treatments for the three variables. Additionally, for the open flowers, there were differences for the two sites with Embu having the highest average of open flowers. The combined treatments of 100g DAP+10kgManure+50g Nitrabor and 20kg Manure+50g Nitrabor showed the best results in terms of flower and fruit formation. Probably the commercial Nitrabor fertilizer (15.4% N + 25.9% CaO + 0.3% B) had an effect on the flowering possibly due to its enhanced boron content and improved solubility of calcium. The unripe fruits on the other hand had significant differences in the seasons but there were no major observational differences between the two sites. This probably can be attributed due to the high number of fruit drop and especially in the Embu which arose as a result of the prolonged dry spell. This study has demonstrates that varying fertilizer application can have significant impact on the flowering and fruit formation of yellow passion which are key determinants of the potential yield of an orchard.