Chemical thinning increasing larger fruits and profit in red guava orchards

The guava is a fruit of strong economic and social relevance, regionally projected and greatly important in some regions of Brazil. The chemical thinning has been adopted in some fruit trees to obtain greater caliber of fruits and better prices. However, some aspects still need to be investigated for the safe and economical viability use of such technique. This research aimed to evaluate the chemical thinning efficiency, production and commercial classification of guava fruits cv. Paluma and provide an economic analysis of this crop system. The ethephon and benzyladenine were applied to fruits with an average size of 18 mm at 0, 150, 300 and 450 mg L-1. The trial was carried out in two crop seasons, and the randomized block design was used as statistical model in a factorial arrangement 2x4. The economic analysis was calculated through total production operational cost, in order to determine gross revenue, net revenue, profitability index, equilibrium price and yield. The benzyladenine and ethephon promoted the highest percentage of thinning fruits at 450 mg L-1, with averages of 67.6% and 70.0%, respectively. However, benzyladenine had a phytotoxic effect when applied at highest concentrations, 300 and 450 mg L-1, respectively. The ethephon enabled greater production of larger caliber fruits in the highest concentration (450 mg L-1). Chemical thinning reduced total operational cost and increased net revenue by 7.57%, as compared to hand thinning. Results also presented that chemical fruit thinning provided equilibrium yield of 4.98 t ha-1 for Paluma guava fruit, as fresh fruit.