The experiment had the purpose to evaluate the effects of pruning, hand thinning and growth regulators sprays to decrease the production alternation and increase the physic-chemical quality of 'Montenegrina' mandarin oranges (Citrus deliciosa Tenore). They are plants budded on 'Caipira' Orange (Citrus sinensis L. Osbeck), and the present study was conducted in a six-year-old commercial orchard, in Panoramas Citrus Company, located in Butiá-RS, Southern of Brazil (29º57'S - 51º40'W). The following treatments were applied: A) Control 1, trees with heavy fruit load; B) Control 2, trees without bearing fruits; C) Hand thinning of 66% of the fruits on heavy loaded trees, in February; D) 200 mg L-1 Ethrel sprays of heavy loaded trees; E) Pruning of heavy loaded trees in December; F) Pruning of heavy loaded trees plus hand thinning in 33% of the fruit; G) Pruning of heavy loaded trees plus 50 mg L-1 of 2,4-DP sprays (95% of 2,4 dichlorofenoxipropionic), at the end of the natural fruit fall in December; H) Pruning of alternate bearing trees in December; I) Pruning of alternate bearing trees plus 10 mg L-1 GA3 giberelic acid sprays (10% of AG3) in May. The treatments were applied in a randomized blocks design with 4 replicates and 3 plants as experimental unit. Pruning decreased the production in each plant in a year of excessive fruit quality, and diminished the alternate bearing of trees associated to the hand thinning practice of 33% of the fruits. In alternate plants, the hand thinning was more efficient to break the production alternation. Hand thinning and pruning of 66% increases the mean mass and better the fruit quality, but the hand thinning of 66% of the fruits was only enough to break the production alternation. Ethephon sprays showed no thinning effect with concentrations of 200 mg L-1 and 10 mg L-1 of GA3 sprays didn't inhibit bud flower differentiation and 50 mg L-1 2,4-DP sprays have no effect on increasing fruit size.
Citrus deliciosa; pruning; hand thinning; growth regulators
