Performance of ‘Hamlin’ Orange on 30 Citrus Rootstocks in Southern Florida

Abstract ‘Hamlin’ orange, Citrus sinensis (L.) Osbeck, was grown on 30 rootstocks for 8 years in an area between Florida's east coast and Lake Okeechobee. There were eight five-tree replications in randomized blocks, with 3×6-m spacing. Yield and fruit quality were determined at four harvests and tree size (trunk cross sectional area) and tree losses were recorded. In general, tree on trifoliate orange [ Poncirus trifoliata (L.) Raf.], trifoliate hybrids, and tangelo ( C. paradisi Macf. × C. reticulata Blanco) rootstocks survived better than trees on mandarin, C. reticulata, and sour orange ( C. aurantium L.) rootstocks. Most of the losses were due to tristeza virus and phytophthora root rot. The largest trees were on Volkamer and rough lemon ( C. limon L. Burm. f.), F 80-18 citrumelo, C. paradisi × P. trifoliata , Troyer citrange, C. sinensis × P. trifoliata, and Sampson tangelo. Fruit production (kg/tree) was best on Volkamer lemon, Swingle, and F 80-18 citrumelo, and hybrid FF 1-131-20 ( C. reticulata × P. trifoliata). In terms of kilograms of solids/tree, trees on Swingle and F 80-18 citrumelo, on hybrid FF 1-131-20, and on Sunshine tangelo were the most productive. Average juice content was low because of two late harvests, but other fruit characteristics were normal. Rind color was exceptionally good on Alamoen shaddock ( C. paradisi).