Tree survival, growth, and juice quality of early-season sweet orange selections on eight rootstocks in Immokalee

William S. Castle, James C. Baldwin


Eight early-maturing sweet orange selections that had been previously evaluated in a formal trial, including two blood oranges, and ‘Earlygold’, ‘Itaborai’, and ‘Ruby’, were planted in a commercial grove in 1995 south of Immokalee. The unreplicated planting was designed to observe performance of these selections on a commercial scale. It consisted of typical double-row beds planted at 10 × 24 ft with trees of one scion per bed divided among eight rootstocks. There were 80–120 trees/bed. After 9 years, the order of tree height across all scions was greatest on Smooth Flat Seville (14.5 ft; 4.4 m) > Goutou > Kinkoji > Benton citrange > Kuharske citrange > Carrizo citrange > Swingle citrumelo > C-35 citrange (11 ft; 3.4 m ). Yield was not measured in the planting, but occasional observation indicated that the trees on each rootstock were cropping at commercially acceptable levels. Using trees on Swingle citrumelo rootstock, juice quality was tracked over four seasons for ‘Earlygold’, ‘Itaborai’, and ’Ruby’ and compared with ‘Hamlin’ fruit collected from a nearby grove. Brix-acid ratios were about 20 by December. Juice color numbers of the three new selections usually exceeded that of ‘Hamlin’ by 1.5–2.0 points by mid-November. Pounds-solids/box were low by industry standards, about 5 pounds/box between mid-November and mid-December, with little difference among all scions. The good tree survival and growth on Smooth Flat Seville and Kinkoji suggested that they were among the most suitable for the site. Trees on C-35 citrange grew well on Wabasso fine sand soil, were relatively smaller in size, but appeared to crop well for their size.

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Proc. Fla. State Hort. Soc.     ISSN 0886-7283