930 PB 536 FORCING METHOD AND ROOTSTOCK AFFECT SCION BUDBREAK AND GROWTH OF CITRUS NURSERY TREES

Abstract

Two experiments were conducted to determine the effects of bud forcing method and rootstock on scion budbreak and nursery tree growth of `Han-din' orange (Citrus sinensis Osb.) In Expt. 1, Carrizo citrange [Citrus sinensis (L.) Osb. × Poncirus trifoliata (L.) Raf.] (Ca), Swingle citrumelo [C. paradisi (L.) Osb. × P. trifoliata (L.) Raf.] (Sw), and Cleopatra mandarin (C. reticulata Blanco) (Cl) were budded with `Hamlin' orange and forced by cutting off the rootstock tops, lopping (cutting half way through the rootstock stem above the scion bud), or bending the rootstock top and tying it to the trunk). For Cl and Ca percent budbreak was high for all forcing methods. For Sw percent budbreak was greater for cutting off than for lopping or bending. For Sw and Ca, bending or lopping resulted in greater whole plant and scion dry weights than cutting off. Expt. 2 was similar to Expt. 1 except that bending was used alone, or in combination with notching (cutting an invertal v-shaped notch above the scion bud), or with topping the bent rootstock shoot. Scion budbreak of Sw plants was greater for bending + notching than for bending alone. Other effects of rootstock and forcing method for cutting off, bending or lopping were similar to those found in Expt. 1.