Tree growth, yield, and fruit quality of nucellar `Frost Marsh Seedless' grapefruit (Citrus paradisi Macf.) on 15 rootstocks were evaluated under Cyprus conditions. Over the 9-year production period, trees on Palestine sweet lime, the group of rough lemon, and Citrus volkameriana Pasq. were more productive per unit of tree size, and their cumulative yields per tree were significantly higher than those of trees on sour orange, which is the standard rootstock commercially used in Cyprus. Rootstocks affected fruit size and weight, rind thickness, juice content, total soluble solids concentration (SSC), and total acids, but the differences were not large enough to affect the market value of the fruit, On the basis of the results of this trial and because sour orange is highly susceptible to tristeza, the C. volkameriana and rough lemon group, which are tolerant to tristeza, should be included in further trial plantings as a potential commercial rootstock.
C.V. Economides and C. Gregoriou
C. Gregoriou and C.V. Economides
Growth, yield, and fruit quality were recorded for Ortanique tangor (Citrus reticulata Blanco) on 11 rootstocks until the trees were 12 years old. Trees on Volkameriana (C. volkameriana Pasq.), rough lemon, and `Estes rough lemon (C. jambhiri Lush.) were more productive per unit of tree size, and their cumulative yields per tree were significantly higher than those of trees on the other rootstocks. There was no significant difference between cumulative yields of Ortanique on the following rootstocks: sour orange (C. aurantium L.), `Palestine' sweet lime (C. limettioides Tan.), `Red' rough lemon (C. jambhiri Lush.), Rangpur (C. limonia Osbeck), and Amblycarpa (C. limonellus var. amblycarpa Hassk.). However, yield on these rootstocks was significantly higher than on Carrizo and Troyer citranges [C. sinensis (L.) Osbeck × Poncirus trifoliata (L.) Raf.] and `Swingle' citrumelo [C. paradisi Macf. × P. trifoliata (L.) Raf.]. The high productivity per unit of tree size of `Palestine' sweet lime suggested that this rootstock could be used advantageously in closely spaced plantings. Rootstocks affected fruit size, weight, rind thickness, juice content, total soluble solids concentration (SSC), and total acids, but the differences were not large enough to be of practical importance.
Frederick S. Davies and Glenn Zalman
fruit quality ( Coggins, 1981 ; Davies, 1986 ). However, several studies have shown that GA 3 application in the fall increased juice content of ‘Pineapple’ oranges by 2% to 10% ( Davies, et al., 1997 , 1999 ), and ‘Hamlin’ oranges by as much as 15
Christopher M. McGuire
Passiflora incarnata L., a perennial vine native to southeastern North America, bears fruit containing an edible juice. I observed the growth, flowering, fruit yield, and fruit traits of P. incarnata plants grown in the field for one season in Ithaca, N.Y. Plants flowered throughout the summer and were pollinated by carpenter bees, but fruit set was low without additional hand-pollination. Fruits set before mid-August matured in 52 to 113 days, but fruits set after mid-August usually failed to mature. Following hand-pollination of some flowers, plants matured 0 to 14 fruits, and yield of edible juice was 5 to 10 mL per fruit. Vegetative growth, plant architecture, number of flowers produced, number of fruits matured, days from flower opening to fruit maturity, fruit size, the proportion of fruits filled with juice and seeds, and the size of juice-containing arils all varied greatly among plants. Part of this variation was probably genetic.
H.K. Wutscher and K.D. Bowman
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.
Ockert P.J. Stander, Karen I. Theron, and Paul J.R. Cronjé
region and stylar end, before being juiced to determine juice content (percentage), TSS (percentage) (PR-32 Palette electronic refractometer; Atago Co, Tokyo, Japan), and TA. Statistical design and analysis. All treatments were applied in a randomized
Juan Carlos Melgar, Jill M. Dunlop, and James P. Syvertsen
). Juice content (%), total soluble solids (°Brix), acidity, and brix:acidity ratio were determined using standard methods approved for Florida orange juice ( Kimball, 1999 ; Wardowski et al., 1995 ). Statistical analysis. The effects of previous
Juan C. Díaz-Pérez, Dan MacLean, Smiljana Goreta, Sarah Workman, Erick Smith, Harwinder Singh Sidhu, Gunawati Gunawan, Anthony Bateman, Jesús Bautista, William Lovett, Maja Jukić Špika, Gvozden Dumičić, and Mira Radunić
in Georgia. Fruit chemical attributes. Fruit juice content ranged from 174 mg·L −1 fruit for ‘Utah Sweet’ to 638 mg·L −1 fruit for ‘Cloud’ ( Table 5 ). The fruit juice content was positively correlated with the aril fraction ( R = 0.562; P < 0
Frederick S. Davies and Glenn Zalman
Our objectives were to determine if gibberellic acid (GA3) application at color break in the fall affected the juice content, soluble solids content (SSC), titratable acid (TA), and ratio of SSC: TA of `Hamlin' orange (Citrus sinensis) fruit following moderate to severe freezes. We also wanted to know if GA3 affected the post-freeze rate of decrease in juice content, fruit and tree cold hardiness, and the amount of fruit drop following a freeze. GA3 (18 floz/acre) was applied at color break in the fall of 2002, 2003, and 2004 to `Hamlin' orange trees on Swingle citrumelo (C. sinensis × Poncirus trifoliata) rootstock planted in 1995 at Gainesville, Fla. Moderate to severe freezes occurred in all three seasons. Fruit were harvested at about 2-week intervals following freezes in each season and the internal fruit quality was determined. GA3-treated fruit generally had higher juice content compared with nontreated fruit for 8 weeks after moderate to severe freezes in all three seasons, which may be economically important to citrus processors and growers since Florida growers are paid based on fruit pounds-solids (juice content × SSC). The rate of decrease in juice content over time was similar for both treatments in seasons one and two, but was less for GA3-treated fruit than nontreated fruit in season three. In addition, SSC was equal to or slightly greater for fruit treated with GA3 than for nontreated fruit. Fruit drop rate and magnitude were also significantly less for the GA-treated compared with nontreated trees in two of three seasons. GA3 did not affect fruit, leaf, or tree cold hardiness in any season.
Since the environmental conditions and cultural practices are unique in southwest Florida, a study was performed to determine the horticultural adaptability and performance of `Valencia' orange trees on four commercial rootstocks grown in a high-density planting. The trees were planted in 1991 on a flatwoods soil in a commercial grove at a density of 627 trees/ha. Leaf mineral concentration, growth, and fruit production and quality were measured 4 and 7 years after planting. Compared to Florida citrus leaf standards, leaf mineral concentration values were within the optimum to the high range. Yield efficiency expressed as kilograms of solids per cubed meter of canopy and juice quality in terms of juice content, soluble solids concentration, and kilograms of solids per box increased with tree age. Tree and fruit size were the highest for Volkamer lemon (Volk) and the lowest for Cleopatra mandarin (Cleo). Fruit yield was the highest for Volk. However, yield expressed in kilograms of solids per hectare was not significantly different between Volk and `Swingle' citrumelo (Swi) due to the higher solids per box for Swi. Yield efficiency was also higher for Swi than for Volk. Juice content and soluble solids in the fruit were higher for Swi and Cleo than for the lemon rootstocks. Financial analysis showed that at high-density planting, trees on Swi were the most profitable. On noncalcareous flatwoods soil, Swi is the best suited rootstock for high-density planting.