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  • Author or Editor: H.K. Wutscher x
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Three trees each of `Valencia' orange (Citrus sinensis L. Osbeck) on rough lemon (C. limon L. Burm. f.) rootstocks that had been grown in solution culture since July 1989 were grown in two solutions from Oct. 1995 to Sept.1996. Solution 1 was a soil extract made by boiling field soil (1:2 soil:water) for 20 min and filtering. Solution 2 was a complete nutrient solution. The solutions were analyzed every 7 days and changed every 28 days. At each solution change, the newly prepared solutions were analyzed for 11 elements and their depletion was determined by weekly analysis. Nearly all the N, K, and Mn in Solution 1 was absorbed in the first 7 days after each solution change; in Solution 2, N and Mn were also absorbed in 7 days, but K absorption was variable; single trees sometimes needed 4 weeks to absorb all the potassium. Calcium and Mg were never completely absorbed and in contrast to Mn, traces of Fe, Zn, and Cu remained in both solutions after 4 weeks.

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Twenty-one selections consisting of 13 numbered hybrids, one ornamental, and seven named cultivars were tested as rootstocks for `Valencia' orange, Citrus sinensis L. Osbeck. The test included six, four-tree replications in randomized complete blocks on sandy soil typical of the center of the Florida peninsula. Trees propagated on Vangasay lemon, HRS 812 (Sunki × Benecke trifoliate orange), and HRS 942 (Sunki × Flying Dragon trifoliate 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 #1, and Tachibana, had low yields and trees on HRS 939 (Flying Dragon trifoliate orange × Nakorn pummelo) and sour orange #2 were extremely dwarfed and were minimally productive because of tristeza virus disease. Fouryear cumulative fruit production ranged from 52 to 317 kg per tree. Fruit from trees on HRS 954 and HRS 952 (Pearl tangelo × Flying Dragon trifoliate orange) had the highest, and fruit from trees on Vangasay and Gou Tou #1 had the lowest total soluble solids concentration.

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Abstract

Sour orange (Citrus aurantium L.) seedlings grown in pots in a greenhouse had 1.8 times as much rubidium in the leaves when larvae of Diaprepes abbreviatus L., the West Indian sugarcane rootstalk borer, were feeding on their roots than weevil-free control trees. Manually inflicted damage to the roots simulating weevil damage had a similar effect. Rubidium uptake could be used to detect root damage as a nondestructive substitute for visual inspection of the roots.

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Abstract

Young grapefruit trees, Citrus paradisi Macf. cv. Redblush, on 20 rootstocks were most productive on Morton citrange [Poncirus trifoliata (L.) Raf. x C. sinensis (L.) Osbeck], Swingle citrumelo (C. paradisi x P. trifoliata), Troyer citrange (P. trifoliata x C. sinensis), Texas sour orange (C. aurantium L.), Changsha mandarin (C. reticulata Blanco) and Christiansen trifoliate orange (Poncirus trifoliata). There were small, but significant differences in fruit quality and uptake of 12 elements.

Open Access
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Abstract

Concentrations of N, P, K, Ca, Mg, Na, Fe, Mn, Zn, Cu, Cl, Mo, and Al varied between blight-affected and healthy trees in one or more of the following ‘Valencia’ orange tree (Citrus sinensis (L.) Osb.) tissues: leaves, twigs, branches, trunks, trunk bark, large roots and feeder roots. Blight had no effect on B concentration; watersoluble phenolics were higher in the trunk wood of blight-affected trees, but not in the wood of branches and roots. Differences in cation exchange capacity, pH and 10 available nutrients in the soil were too small to be significant. The water content of the trunk, branch, and root wood did not vary significantly. The most consistent changes with blight were: higher N levels in the bark and the wood of the trunk; lower K levels in the leaves, coupled with higher K in the wood of the branches and the trunk; higher Na in the leaves and the trunk wood, higher Zn in the leaves and trunk wood; higher Cl concentrations in the leaves and the branch wood together with lower concentrations in the feeder roots.

Open Access

Abstract

Initial growth and development of ‘Valencia’ orange [Citrus sinensis (L.) Osbeck] shoots from buds grafted on 7 different rootstocks were determined during cold-hardening and nonhardening temperature regimes for the 1st 4 months after budbreak. Cold hardening included 12 hr each of 15.6°/4.4°C day/night (D/N) in controlled-environment rooms, where 80% fluorescent and 20% incandescent light averaged 450 μmol m-2s-1. Nonhardening included 32.2°/21.1° D/N as well as greenhouse conditions with natural daylight. Rootstocks influenced growth of ‘Valencia’ during cold-hardening temperatures. Cold-hardening temperatures, however, did not stop ‘Valencia’ growth on any of the rootstocks. Total growth was less than 1/20 of the dry weight accumulated during the warm temperatures. During the cold-hardening treatment, ‘Valencia’ grew the most on the relatively cold-tender volkamer lemon [C. volkameriana (Ten. and Pasq.)] rootstock. The least growth was on the more cold-hardy Swingle citrumelo (C. paradisi Macf. × Poncirus trifoliata (L.) Raf.] rootstock. The amount of growth during cold-hardening temperatures generally coincided with the cold hardiness of the rootstocks, but statistical separation was poor. Trees grown at the warm temperatures started to freeze at higher temperatures than trees grown at cold-hardening temperatures. Rootstocks did not influence freeze avoidance, and no differences were apparent in freeze (ice) tolerance. Three layers of palisade cells were found in leaves that were grown at the cold temperatures.

Open Access

Abstract

In the article “Growth Capacity of ‘Valencia’ Orange Buds on Different Rootstocks during Cold-hardening Temperatures” by G. Yelenosky and H.K. Wutscher [J. Amer. Soc. Hort. Sci. 110(1):78–83. 1985.], the figure captions for Figures 2 and 3 were reversed.

Open Access

Abstract

Sap extracted by nitrogen gas pressure from branches and lateral roots of healthy and citrus blight-affected ‘Hamlin’ and ‘Valencia’ orange, Citrus sinensis (L.) Osbeck, trees on rough lemon (C. Union Burm. f.) rootstock in 2 commercial groves was analyzed for N, K, Ca, Mg, S, Na, Fe, Mn, Zn, Cu, CI, Si, and organic acids. The branch and root wood (from which the sap was extracted), leaves, and feeder roots were also analyzed. Sap extracted from branches of blight-affected ‘Hamlin’ trees in the spring had higher Zn, Cu, CI, and Si concentrations than sap of healthy trees. Nitrogen was increased twofold and Fe slightly increased with blight in the root sap. Branch sap collected from ‘Valencia’ trees in the fall showed no differences. Branch sap contained more organic acids than root sap and there was no difference between blighted and healthy trees. Citric and malic were the principal acids.

Open Access

Abstract

Ten-year tests in 8 locations in the Lower Rio Grande Valley showed that grapefruit (Citrus paradisi Macf.) trees on Swingle citrumelo [C. paradisi x Poncirus trifoliata (L.) Raf.] rootstock grew very poorly on heavy clay soil; trees on sour orange (C. aurantium L.) were much less affected. Trees propagated from a single mother tree of an old-line red grapefruit selection on Swingle citrumelo were stunted and had severe bud union crease, whereas trees propagated from a nucellar California Experiment Station (CES) #3 ‘Redblush’ source were large and productive. Old-clone trees on sour orange also were smaller than CES #3 ‘Redblush’ trees, but showed no bud union crease.

Open Access

Abstract

‘Marrs’ early orange trees, Citrus sinensis (L.) Osbeck, on Swingle citrumelo rootstock were more productive than trees on Texas sour orange, Cleopatra mandarin, and 8 other rootstocks. Fruit from trees on Swingle was large, but had a Brix 0.8% lower than fruit from trees on Texas sour orange, while the acid content was similar. Leaf concentration of 12 elements was affected by rootstocks, especially by Chinese box-orange.

Open Access