Produ？？o da laranjeira-de-umbigo 'Monte Parnaso' com incis？o anelar de ramos e uso de reguladores vegetais

in order to reduce early fruit drop and increment fruit production of 'monte parnaso' oranges (citrus sinensis [l.] osbeck), during the season 2001/2002 orange trees from an 11 years old orchard grafted onto poncirus trifoliata (l.) raf. located in butiá, rio grande do sul, brazil, were submitted to the following treatments: 1) control (no girdling and no growth regulator sprays); 2) girdling of branches after 10 days of petal drop; 3) girdling of branches after june drop; 4) 5 mg.l-1 of ga3 sprayed 10 days after petal drop; 5) 15 mg.l-1 of 2,4-d sprayed at the end of june drop; 6) 50 mg.l-1 of 2,4-d sprayed at the end of june drop; 7) 10 mg.l-1 of ga3 plus 15 mg.l-1 of 2,4-d sprayed on may 14th, 2001 and may 11th, 2002; 8) combination of treatments 2 and 3; 9) combination of treatments 2, 3 and 7. the experiment was conducted in a randomized block design with 5 replicates and 3 trees as experimental units. the results indicate that spraying 5 mg.l-1 of ga3 10 days after petal drop increase fruit weight production but reduce fruit average weight in relation to other treatments that enhances the fruit production; spraying 15 mg.l-1 of 2,4-d in november after june drop reduce fruit juice content; and to have higher fruit production one of the following procedures are recommended: girdling of branches or spraying 5 mg.l-1 of ga3 10 days after petal drop, spraying 15mg.l-1 or 50 mg.l-1 of 2,4-d in november after june drop or spraying orange trees with 10 mg.l-1 of ga3 plus 15 mg.l-1 of 2,4-d in may.