Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 18, 1998
Publication Date: N/A
Interpretive Summary: Disease outbreaks and low prices have put the Florida citrus industry under pressure. The best way to get resistance for many diseases and so raise quality and quantity of fruit production is through the use of new rootstocks. We tested 13 USDA-developed new hybrid rootstocks against five commercially used and two imported rootstocks, with Valencia tops. Three rootstocks induced superior fruit production, one of them on large trees with several weaknesses, the other two on medium to small trees with high fruit quality. After these two rootstocks are tested in commercial-sized plantings, they may solve some of the industry's problems.
Technical Abstract: Twenty-one selections consisting of 13 numbered hybrids, 1 ornamental, and 7 named cultivars were tested as rootstocks for Valencia' orange, Citrus sinensis L. Osbeck. The test included 6 four-tree replications in randomized, complete blocks on sandy soil typical of the center of the Florida peninsula. Trees on Vangasay lemon, HRS 812 (Sunki X Benecke trifoliate orange), and HRS 942 (Sunki X Flying Dragon triofoliate orange) produced more fruit than trees on the other 18 rootstocks in the test. Trees on 10 rootstocks, including the widely used commercial rootstocks,Swingle citrumelo and Carrizo citrange, were intermediate in cumulative fruit production. Trees on five rootstocks, including Sun Chu Sha , Gou Tou, and Tachibana, had low yields and trees on HRS 939 (Flying Dragon trifoliate X Nakorn pummelo) and sour orange #2 were extremely dwarfed and were minimally productive because of tristeza virus disease. Four-year cumulative fruit production ranged from 52 to 317 kg per tree. Fruit from trees on HRS 954 and HRS 952 (Pearl tangelo X Flying Dragon trifoliate orange) had the highest, fruit from trees on Vangasay and Gou Tou had the lowest soluble solids concentration.