Abstract
A 'Washington' navel (nucellar budline N-S-F-56-11- X-E) orange [Citrus sinensis (L.) Osbeck] rootstock trial involving eight rootstocks was planted in Astatula fine sand soil at 116 trees/acre at Mt. Dora. A 1989 freeze damaged most trees except those on Swingle citrumelo [C. paradisi Macf. × Poncirus trifoliata (L.)Raf.], sour orange (C. aurantium L.), and × 639 [Cleopatra mandarin (C. reticulata Blanco) × P. trifoliata] which had 78% to 100% survival. A second trial planted in 1991 replaced the original one at Mt. Dora along with a third trial planted at Ft. Pierce in Pineda sand soil at 167 trees/acre. Trees on Swingle citrumelo, Cleopatra mandarin, and Sun Chu Sha mandarin were common to both 1991 trials with the remaining rootstocks being mostly citrumelos, citranges [C. sinensis (L.) Osb. × P. trifoliata], somatic hybrids, and other citrus hybrids with trifoliate orange. Yield was measured in each of the first years after the trees began to crop. Fruit samples were collected to determine juice quality. Tree heights at both locations were measured near the end of the experiments and ranged from about 6 to 11 ft. The smaller trees were those on Rusk citrange and the somatic hybrids; the tallest trees were generally those on the mandarin rootstocks. Annual yields varied from about 1 to 2 boxes/tree. The most productive trees ( >4 boxes/tree cumulative yield) in Ft. Pierce were those on W-2 citrumelo, C-32 citrange, and x639, and in Mt. Dora they were those on W-2 and Swingle citrumelos, sour orange, and Rusk and Koethen × Rubidou × citranges.
