Chemical thinning increasing larger fruits and profit in red guava orchards

Abstract

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 replicated trial in two crop cycles was in randomized block design in a factorial arrangement 2x4. The economic analysis was calculated through total production operational cost, in order to determine gross revenue, operating profit, 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 operating profit 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.