Effect Of Vine Lengthon Growth, Yield And Nutrient Concentrationof Sweet Yellow Passion Fruits (Passiflora Edulis Var. Flavicarpa) In Embu County, Kenya

ABSTRACT

Sweet yellow passion fruit (Passiflora edulis var. flavicarpa) is widely gaining adoption in Kenya, emerging as an important high market value horticultural crop. However, its current yields are low due to poor agronomic practices among other reasons. The objectives of this study were to determine the effect of vine length on growth, yield and nutrient concentration of sweet yellow passion fruits in Embu County and evaluating orchard management practices for sweet yellow passion fruits by farmers, with a special focus on canopy management. The study involved a survey study and a field experiment and which were conducted in Embu County, Kenya. The experiment was carried out in two sites; Ugweri and Kigumo, Embu County from April 2016 to September 2017. The field experiment was established in a Randomized Complete Block Design. Four treatments of varying vine lengths were applied namely; 3 m (Conventional) 4 m, 5 m and 3 m double. The data collected were subjected to ANOVA using Statistical Analysis Software (SAS) version 9.3 and means were separated using LSD at probability level of 5 %. The survey was carried out on sweet yellow passion fruit farms in Embu East Sub- County, Kenya. The farmers were randomly sampled using a stratified sampling procedure. Personal interviews with farmers of sweet yellow passion fruit were carried out in selected households using structured and semi- structured questionnaires from June 2016 to August 2016. The survey data was analysed using SPSS version 20. Correlation between pruning intensity and dieback disease incidence was analysed using Pearson’s Correlation model. Findings from the study showed that pruning intensity among farmers varied from very low, moderate to very high. The results showed that 9.8 % of farmers pruned moderately, 58.8 % of farmers pruned with a low pruning intensity and 29.4 % of farmers pruned with a very low pruning intensity. Pruning intensity was negatively correlated (-0.265) to dieback incidence with a P value of 0.040. The results imply that most farmers pruned the vines at low intensity with the aim of retaining more vines. However, this resulted to more incidence of the dieback disease. This study revealed that 4 m vine showed the highest photosynthetically active radiation (984.67 μmols/m2s), followed by 3 m conventional (917 μmols/m2s), 5 m (709.67 μmols/m2s) and last 3 m double (566.67 μmols/m2s) at 26 weeks after transplanting (WAT) in Kigumo. The 4 m vine recorded the highest level of N in leaf tissue both at Kigumo (3.99%) and Ugweri (5.79%) indicating a higher photosynthetic potential than 3 m conventional, 5 m and 3 m double vines. The 3 m double vine recorded the highest number of fruits per vine in Kigumo (174.67) and Ugweri (148.67), but had the lowest fruit girth of 5.04cm and 4.54cm, and length of 6.31cm and 5.94cm compared to 3 m conventional, 4 m and 5 m vines in Kigumo and Ugweri respectively at 39 WAT. This shows that 3 m double vine produced the highest quantity of fruits of smaller size compared to 3 m conventional, 5 m and 4 m vines. The findings from this study reveal that farmers in Embu County are required to practise moderate pruning to provide an appropriate canopy size which would improve productivity of sweet yellow passion fruits. Further research on 3 m double vine density should be conducted to evaluate the proper pruning regime that could optimize yield of marketable quality under the available resources.