Manual thinning of tangerine 'Montenegrina'

Hand thinning of 66.6% or 83.3% of young fruits, at different intervals, was tested with the objective to avoid biennial bearing and to improve fruit quality of 'Montenegrina' tangerines (Citrus deliciosa Tenore). The experiment was conducted during four harvesting seasons on a 10-year old orchard at the Estação Experimental Agronômica of the Universidade Federal do Rio Grande do Sul, located in Eldorado do Sul - Southern Brazil. Both thinning intensities of young fruits, reduced biennial bearing. Thinning of 66.6% was more efficient for the stabilization of the production of marketable fruits on trees with a medium initial fruit set while thinning of 83.3% produced better results on trees with a high initial fruit set. With these experiments it became evident that fruit thinning has to be done every two years.