Off-Season Flower Induction in Mango Fruits Using Ethephon and Potassium Nitrate

Seasonality in mango production is a major factor contributing to high postharvest losses reported in the value chain. Oversupply during the high season is one of the factors that contribute to the high postharvest losses (≥ 50%) in the supply chain in Kenya. Effective strategies to address seasonality can contribute significantly to postharvest loss reduction. Efficacy of two flower induction chemicals, potassium nitrate (KNO3) and ethephon on reproductive growth parameters and yield components were evaluated on two mango varieties- ‘Apple’ and ‘Ngowe’. KNO3 was applied at two concentrations (2 and 4%), and ethephon (600 and 1000 ppm) then compared to control (water). They were applied to trees which failed to flower/set fruit in 2014 season. There effect was established from reproductive growth parameters- days to flowering, number of panicles per tree, fruit set per 20 panicles, fruit fall and hormonal effect. KNO3 (4%) and ethephon increased percentage flowering in both ‘Ngowe’ and ‘Apple’ and AEZs (Agro-Ecological Zones), significantly (p < 0.05) shortened time to flowering and increased fruit set. The findings show that KNO3 and ethephon can be used to induce flowering/fruiting in mango fruits. These technologies can therefore be applied to induce off-season mango production to address seasonality and reduce postharvest losses during the peak season.