Midseason oranges for juice production

1992 ◽  
Vol 32 (8) ◽  
pp. 1141 ◽  
Author(s):  
RA Sarooshi ◽  
RJ Hutton
Keyword(s):  
Orange Juice ◽  
Sweet Orange ◽  
Quality Characteristics ◽  
Poncirus Trifoliata ◽  
Soluble Solids ◽  
Juice Quality ◽  
Rough Lemon ◽  
Large Trees ◽  
Production Areas ◽  
Troyer Citrange

Juice quality, yield performance, and cropping efficiency of 6 midseason orange varieties (Hamlin, Parramatta, Pineapple, Joppa, White Siletta, and Mediterranean Sweet), together with Seedless Valencia on 4 rootstocks [Troyer citrange, Poncirus trifoliata, rough lemon, and either Benton citrange (coastal) or sweet orange (inland)], were studied for their suitability for both processed and fresh orange juice production. Promising midseason varieties for processed orange juice were Parramatta and Hamlin on Troyer citrange, and Parramatta on P. trifoliata, when grown in coastal districts. Debittered juice of Joppa on Troyer citrange could also be used for processing by early September on the coast. Preferred inland varieties for production of processed orange juice were Mediterranean Sweet and Harnlin on Troyer citrange. Midseason oranges grown inland had higher citric acid levels than the same variety grown on the coast. This resulted in inland fruit having lower ratios of total soluble solids (TSS) to acid, and later maturities, than fruit grown on the coast. Acceptable fresh orange juice was produced from fruit of Parramatta, Hamlin, White Siletta, and Mediterranean Sweet varieties grown on Troyer citrange rootstock in coastal districts; inland, fruit of Mediterranean Sweet, Joppa, Parramatta, and White Siletta varieties on Troyer citrange rootstock produced good quality, fresh orange juice. Hamlin can also be marketed as fresh fruit. In coastal production areas, harvesting can commence from mid July for Hamlin, from mid to late August for Parramata, and from early September for White Siletta and Mediterranean Sweet. Harvest in inland districts for processed juice should commence in mid July for Hamlin and in early September for Mediterranean Sweet, whilst harvest for fresh juice and/or fruit should proceed in early September for Mediterranean Sweet, and in late September for Parramatta, White Siletta, and Joppa. Highest fruit yields and large trees were produced by Parramatta and Joppa on Troyer citrange and rough lemon rootstocks. Most quality characteristics were better for fruit produced on Troyer citrange than on rough lemon. Both Benton citrange and sweet orange performed poorly and are not recommended as rootstocks for midseason oranges. All varieties on Troyer citrange had better yield and TSS/ha than those on P. trifoliata rootstock, which produced smaller but highly cropping efficient trees.

scholarly journals Soluble Solids Accumulation in `Valencia' Sweet Orange as Related to Rootstock Selection and Fruit Size

2004 ◽  
Vol 129 (4) ◽  
pp. 594-598 ◽  
Author(s):  
Graham H. Barry ◽  
William S. Castle ◽  
Frederick S. Davies
Keyword(s):  
Sweet Orange ◽  
Fruit Size ◽  
Poncirus Trifoliata ◽  
Soluble Solids ◽  
Quality Data ◽  
Juice Quality ◽  
Direct Role ◽  
Size Category ◽  
Carrizo Citrange ◽  
Rough Lemon

Juice quality of `Valencia' sweet orange [Citrus sinensis (L.) Osb.] trees on Carrizo citrange [C. sinensis × Poncirus trifoliata (L.) Raf.] or rough lemon (C. jambhiri Lush.) rootstocks was determined for fruit harvested by canopy quadrant and separated into size categories to ascertain the direct role of rootstock selection on juice soluble solids concentration (SSC) and soluble solids (SS) production per tree of citrus fruit. SS production per fruit and per tree for each size category was calculated. Juice quality was dependent on rootstock selection and fruit size, but independent of canopy quadrant. Fruit from trees on Carrizo citrange had >20% higher SSCs than fruit from trees on rough lemon, even for fruit of the same size. Large fruit accumulated more SS per fruit than smaller fruit, despite lower juice content and SSC. Within rootstocks, SS content per fruit decreased with decreasing fruit size, even though SSC increased. Rootstock effect on juice quality was a direct rather than an indirect one mediated through differences in fruit size. The conventional interpretation of juice quality data that differences in SSC among treatments, e.g., rootstocks or irrigation levels, or fruit size, are due to “dilution” of SS as a result of differences in fruit size and, hence, juice volume, is only partly supported by these data. Rather, accumulation of SS was greater for fruit from trees on Carrizo citrange than rough lemon by 25% to 30%.

scholarly journals Rootstocks and the Performance and Economic Returns of ‘Hamlin’ Sweet Orange Trees

HortScience ◽  
2010 ◽  
Vol 45 (6) ◽  
pp. 875-881 ◽  
Author(s):  
William S. Castle ◽  
James C. Baldwin ◽  
Ronald P. Muraro
Keyword(s):  
Financial Analysis ◽  
Sweet Orange ◽  
Block Design ◽  
Tree Height ◽  
Poncirus Trifoliata ◽  
Soluble Solids ◽  
Juice Quality ◽  
Volkamer Lemon ◽  
C 32 ◽  
Orange Trees

‘Hamlin’ is a principal sweet orange grown in Florida for processing. It is productive but produces juice with low soluble solids content and poor color. A long-term trial was conducted in central Florida to determine rootstock effects on yield and juice quality and the effect of economic analysis on the interpretation of the horticultural results. The trees were a commonly used commercial selection of ‘Hamlin’ sweet orange [Citrus sinensis (L.) Osb.] propagated on 19 rootstocks planted in a randomized complete block design of three-tree plots with six replicates in a Spodosol soil at a density of 350 trees/ha. Routine horticultural data were collected from the original trial (H1) for 10 years. Trees on some rootstocks that grew and yielded poorly were removed within a few years and replaced with a second trial (H2) with 13 rootstocks from which data were collected for 5 years. The H1 data were financially analyzed to compare the relative usefulness of horticultural and economic data in interpreting results and making rootstock decisions. In H1 after 10 years, tree height ranged from greater than 5 m [Volkamer lemon (C. volkameriana Ten. & Pasq.)] and Cleopatra mandarin (C. reshni Hort. ex Tan.) to 2.4 m {Flying Dragon trifoliate orange [Poncirus trifoliata (L.) Raf. ]}. In H2, the trees on somatic hybrid rootstocks were ≈2 m tall after 8 years and 4.4 m among those on mandarins and C-32 citrange (C. sinensis × P. trifoliata). Tree losses from citrus blight were generally low except for the trees on Carrizo and Troyer citranges (greater than 50%). Horticulturally, the highest performing trees in H1, measured by cumulative yield and soluble solids production over 10 years, were those on Carrizo, Troyer, and Benton citranges; poor performers were those on Smooth Flat Seville and Kinkoji (putative sour orange hybrids). Fruit yield and soluble solids production were directly related to tree height regardless of the difference among rootstocks in juice quality. The same relationship existed among the trees in H2 in which the best rootstocks were C-32 and Morton citranges. Trees on Swingle citrumelo (C. paradisi Macf. × P. trifoliata) ranked no. 12 of 19 rootstocks and 9 of 13 rootstocks in H1 and H2, respectively. Financial interpretation of the outcomes to include tree replacement resulting from blight losses did not substantially change the horticultural interpretations. Additional financial analyses demonstrated that the performance of trees on rootstocks with relatively low productivity/tree, like those on C-35 citrange and Kinkoji, would equal those on more vigorous rootstocks when tree vigor was properly matched with spacing. Yield determined the economic outcomes and financial analysis aided the interpretation of rootstock horticultural effects but did not greatly alter the relationship among rootstock results. Highly significant correlations between annual and cumulative data indicated that relative rootstock performance among ‘Hamlin’ orange trees in Florida could be reliably determined based on the first 4 cropping years.

scholarly journals Performance of ‘Valencia’ Sweet Orange Trees on 12 Rootstocks at Two Locations and an Economic Interpretation as a Basis for Rootstock Selection

HortScience ◽  
2010 ◽  
Vol 45 (4) ◽  
pp. 523-533 ◽  
Author(s):  
William S. Castle ◽  
James C. Baldwin ◽  
Ronald P. Muraro ◽  
Ramon Littell
Keyword(s):  
Financial Analysis ◽  
Sweet Orange ◽  
Poncirus Trifoliata ◽  
Soluble Solids ◽  
Juice Quality ◽  
Sour Orange ◽  
Central Florida ◽  
Carrizo Citrange ◽  
Acid Ratio ◽  
Fruit Samples

Two field experiments with ‘Valencia’ sweet orange [Citrus sinensis (L.) Osb.] trees propagated on 12 rootstocks were conducted in commercial orchards. The objectives were to compare rootstock horticultural performance between two locations with soils representative of the Central Florida Ridge (AP) and coastal flatwoods (I), the major citrus-growing regions in Florida, and to see if financial analysis would provide an improved basis for interpreting rootstock performance. The randomized complete-block trials involved six-tree plots replicated eight or 10 times at planting densities of 358 trees (AP) or 252 trees (I)/ha, respectively. Tree growth and survival, yield, and juice quality were measured for 15 years. When losses occurred, trees were replaced annually with another one on the same rootstock. The data of seven rootstocks were subjected to a financial interpretation of three scenarios: tree loss and tree loss with or without tree replacement using the discounted cash flow and internal rate of return methods at a 15% rate. At the flatwoods location, when differences among replications became apparent on several rootstocks, soil data were collected to study its possible association to tree performance; also in this trial, 400-kg fruit samples were differentially harvested in 2 successive years from mature trees on each of five commercial rootstocks when the juice soluble solids/acid ratio was near 15. The juice was extracted, pasteurized, and evaluated for flavor by an experienced taste panel. The horticultural data obtained for trees on specific well-studied rootstocks [Volkamer (C. volkameriana Ten. & Pasq.)] and rough (C. jambhiri Lush.) lemons, Carrizo citrange [C. sinensis × Poncirus trifoliata (L.)], sour orange [C. aurantium (L.)], Cleopatra mandarin (C. reshni Hort. ex Tan.), trifoliate orange (P. trifoliata), a selection of sweet orange (C. sinensis), and Swingle citrumelo (C. paradisi Macf. × P. trifoliata) at both locations were typical of their well-documented performance in Florida and elsewhere. Tree losses were virtually only from citrus blight and ranged from none (sour orange) to greater than 50% (Volkamer and rough lemons) at both locations, although tree loss began later at the Central Florida location. ‘Valencia’ cuttings (only at the flatwoods site) were long-lived and cropped well for their smaller size compared with the budded trees. Taste panelists were not able to distinguish differences over two seasons among pasteurized ‘Valencia’ juices produced from trees on different rootstocks and normalized by soluble solids/acid ratio. Yield and planting density were the main factors affecting financial outcome; also, in the highly variable soils of the coastal flatwoods, trees growing in sites with greater depth to an argillic layer had 30% to 200% higher yields. Trees on Volkamer lemon had only ≈50% survival at both locations but had the highest ($7,338/ha I) or one of the highest cash flows ($13,464/ha AP) as compared with one of the commercial standards, Carrizo citrange ($6,928 I; $16,826 AP), which had only ≈25% tree loss. Inclusion of financial analysis, with certain limitations, was concluded to considerably improve rootstock selection decisions compared with selection based only on horticultural data.

scholarly journals Juice Quality of `Valencia' Sweet Oranges Borne on Different Inflorescence Types

HortScience ◽  
2004 ◽  
Vol 39 (1) ◽  
pp. 33-35 ◽  
Author(s):  
Graham H. Barry ◽  
William S. Castle ◽  
Frederick S. Davies
Keyword(s):  
Sweet Orange ◽  
Fruit Size ◽  
Titratable Acidity ◽  
Poncirus Trifoliata ◽  
Soluble Solids ◽  
Minor Effect ◽  
Juice Quality ◽  
Canopy Position ◽  
Inflorescence Type

The objectives of this study were to determine whether juice quality of `Valencia' sweet orange [C. sinensis (L.) Osb.] is affected by the type of inflorescence on which fruit are borne, and to determine the contribution of inflorescence type to within-tree variation in juice quality. During the 1998-99 and 1999-2000 seasons, fruit size and juice quality [soluble solids concentration (SSC) and titratable acidity (TA)] of fruit from `Valencia' sweet orange trees on Carrizo citrange rootstock [Poncirus trifoliata (L.) Raf. × C. sinensis (L.) Osb.] planted in 1987 at Howey-in-the-Hills, Fla., were measured. A 2×2 factorial design (inflorescence type × canopy position) with leafy and leafless inflorescence types, and southwest top and northeast bottom canopy positions was used. The type of inflorescence on which fruit were borne had a minor effect on juice quality, and inflorescence type and juice quality were not directly associated. Rather, juice SSC was associated with the effect of inflorescence type on fruit size, as small fruit tended to have higher SSC than large fruit, regardless of the type of inflorescence on which fruit were borne. The relatively small difference in SSC between fruit borne on leafy and leafless inflorescences (≈3% of mean SSC) was an indirect result of fruit size. Therefore, fruit borne on leafy inflorescences, which tend to be of larger size compared with fruit borne on leafless inflorescences, tended to have marginally lower SSC. Acid content and ratio of SSC: TA were not related to inflorescence type. In addition, the type of inflorescence on which fruit were borne made only a nominal contribution to variability in juice SSC, in contrast to the major contribution of canopy position to within-tree variation in juice SSC. Factors other than inflorescence type are important components of within-tree variation in juice SSC.

scholarly journals Variability in Juice Quality of `Valencia' Sweet Orange and Sample Size Estimation for Juice Quality Experiments

2003 ◽  
Vol 128 (6) ◽  
pp. 803-808 ◽  
Author(s):  
Graham H. Barry ◽  
William S. Castle ◽  
Frederick S. Davies ◽  
Ramon C. Littell
Keyword(s):  
Sweet Orange ◽  
Titratable Acidity ◽  
Poncirus Trifoliata ◽  
Soluble Solids ◽  
Juice Quality ◽  
Size Estimation ◽  
Solids Concentration ◽  
Fruit Samples ◽  
Sources Of Variation

Sources of variation in juice quality of `Valencia'sweet orange [Citrus sinensis(L.) Osb.] were quantified and their relative contributions to variability in juice quality were determined, from which sample sizes were estimated. Commercial orchards of `Valencia' sweet orange trees on Carrizo citrange [C. sinensis × Poncirus trifoliata (L.) Raf.] rootstock were selected at four geographic locations representing the major citrus-producing regions in Florida. Within- and between-tree variation in soluble solids concentration (SSC) and titratable acidity (TA) were estimated in two experiments over two or three seasons, respectively. Variance components for all treatment effects were estimated to partition total variation into all possible component sources of variation. Seasonal variation in SSC and TA was relatively small, but larger for TA than SSC. Variation in SSC among blocks within a location was intermediate to low, and was less than variation among locations. In contrast, tree-to-tree variation in SSC and TA was large, in spite of sampling from trees of similar vigor and crop load, and variation in SSC and TA among fruit was relatively large. Based on results of this study, samples consisting of 35 fruit are required to detect differences (P ≤ 0.05) of 0.3% SSC and 0.06% TA, whereas 20-fruit samples can be used to detect differences of 0.4% SSC and 0.08% TA. Seven replications are required to detect differences of 0.5% SSC and 0.1% TA, with small gains in precision when tree numbers exceed 10.

scholarly journals Young-tree Performance of Juvenile Sweet Orange Scions on Swingle Citrumelo Rootstock

HortScience ◽  
2011 ◽  
Vol 46 (4) ◽  
pp. 541-552 ◽  
Author(s):  
William S. Castle ◽  
James C. Baldwin
Keyword(s):  
Sweet Orange ◽  
Early Spring ◽  
Poncirus Trifoliata ◽  
Soluble Solids ◽  
Juice Quality ◽  
Cumulative Yield ◽  
Young Tree ◽  
Late Season ◽  
Swingle Citrumelo ◽  
Blood Orange

A worldwide search was conducted for sweet orange [Citrus sinensis (L.) Osb.] selections with higher yield and better juice quality than existing commercial cultivars used in Florida primarily by the processing industry. Seeds of nearly 100 selections were introduced, germinated, and used as a source of buds for propagation. The scion selections were divided among six trials established by propagating juvenile buds from ≈12-month-old scion seedlings onto Swingle citrumelo [C. paradisi Macf. × Poncirus trifoliata (L.) Raf.] rootstock plants already in place in the field. Comparison trees using buds from mature sources were produced in a commercial nursery. The trials consisted of four to five replications of one- or two-tree plots with trees planted 4.3 × 6.7 m within and between rows, respectively. The scions were early-maturing (fall to early winter), midseason (winter to early spring), and late-season (early spring to early summer) common orange, blood orange, and ‘Pera’ orange selections. Data collected routinely included seed counts, standard measurements of juice quality, and yield during an ≈13-year period of evaluation. All trees exhibited typical juvenile traits such as vigor and thorniness; however, flowering and first cropping were not substantially delayed. Many selections began fruiting within 3 years after planting, which is the common commercial experience among trees propagated with mature bud sources. Many selections were low-seeded with counts of less than 10/fruit. Mean cumulative yield (8 years) among the early- and midseason selections in the first-planted trial was 1390 kg/tree and ranged to a high of 1751 kg/tree; for the late-season types, the mean was 947 kg/tree with little variability among eight selections. The yields of the early- to late-season selections in the other trials were similar. The blood orange selections proved to be mostly midseason in maturity. They lacked the deep peel and flesh coloration of blood oranges grown in a Mediterranean-type climate, but some selections did develop an enhanced orange color of the juice and the different flavor typical of blood oranges. ‘Pera’ orange selections exhibited a bud union incompatibility and subsequent decline with Swingle citrumelo rootstock and also when another sweet orange was inserted as an interstock. Their mean cumulative yield over six seasons was 797 kg/tree with an ≈30% difference between the lowest and highest values. Juice soluble solids, acid, and color values were typical of ‘Pera’ fruit grown in Brazil. The overall collection of sweet oranges displayed considerable diversity in their traits despite their supposed origin as a monophyletic group. Several early-season selections were released for commercialization, including ‘Earlygold’ and ‘Itaborai’, because of their better juice color and flavor. ‘Vernia’, a midseason selection, was released because of its high juice quality in late winter–early spring and its cropping precocity.

scholarly journals Yield, Fruit Damage, Yield Loss, and Juice Quality Characteristics of Machine- and Hand-harvested ‘Brown Snout’ Specialty Cider Apples Stored at Ambient Conditions in Northwest Washington

2016 ◽  
Vol 26 (5) ◽  
pp. 614-619
Author(s):  
Travis Robert Alexander ◽  
Jaqueline King ◽  
Edward Scheenstra ◽  
Carol A. Miles
Keyword(s):  
Yield Loss ◽  
Titratable Acidity ◽  
Quality Characteristics ◽  
Soluble Solids ◽  
Juice Quality ◽  
Ambient Conditions ◽  
Storage Duration ◽  
Phenolic Contents ◽  
Fruit Damage ◽  
Mechanical Harvester

In this 2-year study, ‘Brown Snout’ specialty cider apples (Malus ×domestica) that had been hand harvested or machine harvested with an over-the-row shake-and-catch small fruit harvester were ambient stored (56 °F mean temperature) for 0, 2, and 4 weeks to evaluate yield, fruit damage, yield loss, and juice quality characteristics. The average yield (pounds per acre) of fruit picked and retained by the mechanical harvester was 74% that of the hand-harvest yield and 81% that of the hand-harvest yield when fruit that fell out of the harvester was included in the machine-harvest yield. Percent fruit bruised and cut were greater for machine harvest (97.5% and 25.5%, respectively) than for hand harvest (47% and 0.5%, respectively), on average for 2014 and 2015. Yield loss to rot was greater for machine harvest than for hand harvest, and increased for both methods over time; percent rot doubled from 2 to 4 weeks storage for machine harvest (22% to 41%), and while negligible, tripled from 2 to 4 weeks storage for hand harvest (0.7% to 2.1%). Juice quality characteristics did not differ due to harvest method, but did differ due to year and storage time. Soluble solids concentration [SSC (%)] and specific gravity (SG) did not change due to storage in 2014, but in 2015, SSC and SG were greater on average for 2 and 4 weeks storage duration (15% and 1.062, respectively) than at harvest (13.31% and 1.056, respectively). Titratable acidity (grams per liter malic acid) decreased in 2014 from 2.98 g·L−1 at harvest to 2.70 g·L−1 on average for 2 and 4 weeks storage duration, but did not differ due to storage in 2015. Tannin [tannic acid equivalent (%)] was unchanged in 2014 from harvest to 4 weeks storage, but increased in 2015 from 0.16% at harvest to 0.19% by 4 weeks storage. These results indicate that harvest efficiency could be improved with some engineering modifications of the over-the-row mechanical harvester and training modifications for the trees. A comparison of the aromatic and phenolic contents of mechanically harvested and hand-harvested ‘Brown Snout’ would be a valuable next step in evaluating shake-and-catch mechanical harvest technology for cider apple production.

scholarly journals Rootstocks Affect Tree Growth, Yield, and Juice Quality of ‘Marsh’ Grapefruit

HortScience ◽  
2011 ◽  
Vol 46 (6) ◽  
pp. 841-848 ◽  
Author(s):  
William S. Castle ◽  
Kim D. Bowman ◽  
James C. Baldwin ◽  
Jude W. Grosser ◽  
Frederick G. Gmitter
Keyword(s):  
Growth Yield ◽  
Tree Height ◽  
Poncirus Trifoliata ◽  
Soluble Solids ◽  
Quality Data ◽  
Juice Quality ◽  
Sour Orange ◽  
Citrus Paradisi ◽  
High Productivity ◽  
River Region

Two adjacent rootstock trials were conducted in the east coast Indian River region of Florida with ‘Marsh’ grapefruit (Citrus paradisi Macf.) scion. The objective was to find rootstocks to replace sour orange (C. aurantium L.) because of losses to citrus tristeza virus, and to replace Swingle citrumelo [C. paradisi × Poncirus trifoliata (L.) Raf.] because of its limited usefulness in certain poorly drained coastal sites. The trials were conducted in randomized complete blocks with 12 single-tree replicates spaced 4.6 × 6.9 m. The soils were of the Wabasso and Riviera series. The first trial consisted largely of trees on citrange [C. sinensis (L.) Osb. × P. trifoliata] and citrumelo rootstocks, ‘Cipo’ sweet orange (C. sinensis), and various hybrid rootstocks. The second trial involved mandarin rootstocks (C. reticulata Blanco) and sour orange and related rootstocks. Trees were grown for 7 years and yield and juice quality data were collected for the last 4 years of that period. Those rootstocks identified as the most promising, based on combinations of smaller tree size and high productivity and juice quality, were two Sunki mandarin × Swingle trifoliate orange (TF) hybrids (C-54, C-146), a Sunki mandarin × Flying Dragon TF hybrid, C-35 citrange, and a Cleopatra mandarin × Rubidoux TF hybrid (×639). The trees on these five rootstocks cropped well leading to soluble solids (SS) values of 3000 to 4000 kg/ha when they were 7-years old. The trees on C-54 and C-146 were relatively large, somewhat taller than trees on sour orange, whereas those on C-35 and the Sunki × Flying Dragon hybrid were smaller and similar to sour orange in tree height. Fruit quality among the trees on C-35 and the Sunki × Flying Dragon hybrid had relatively high SS concentration (better than sour orange), and the other three rootstocks had relatively lower solids concentration (poorer than sour orange). The trees on C-35 and the Sunki × Flying Dragon hybrid would be good candidates for higher density orchards.

Uptake and distribution of chloride, sodium and potassium ions in salt-treated citrus plants

1983 ◽  
Vol 34 (2) ◽  
pp. 133 ◽  
Author(s):  
AM Grieve ◽  
RR Walker
Keyword(s):  
Sweet Orange ◽  
Poncirus Trifoliata ◽  
Potassium Ions ◽  
Citrus Reticulata ◽  
Rangpur Lime ◽  
Rough Lemon ◽  
Young Leaves ◽  
Chloride Accumulation ◽  
Sodium And Potassium ◽  
Cleopatra Mandarin

Seedlings of a range of citrus rootstocks were grown under glasshouse conditions and supplied with dilute nutrient solution containing either 0 or 50 mM NaCl. The partitioning of accumulated chloride and sodium into and within the major organs was compared between plants of Rangpur lime (Citrus reticulata var. austera hybrid?), Trifoliata (Poncirus trifoliata) and sweet orange (C. sinensis). Rootstocks differed in their leaf and stem chloride and sodium concentrations, but there was little or no difference between the rootstocks in root chloride and sodium concentrations. The lowest leaf chloride and sodium concentrations were found in the top region of shoots of all rootstocks. The different patterns of accumulation of chloride and sodium found in the three rootstocks were consistent with the existence of apparently separate mechanisms which operate to limit the transport of these two ions from the roots into the young leaves of citrus plants. The chloride excluding ability of 10 rootstocks and two hybrids was also compared and assessed in relation to rootstock vigour. Sampling from the middle leaves on salt-treated plants enabled a distinction to be made between rootstocks in their chloride accumulation properties. Cleopatra mandarin (C. reticulata), Rangpur lime, Macrophylla (C. macrophylla) and Appleby smooth Seville (C. paradisi x C. sinensis) accumulated significantly less chloride than did Trifoliata and rough lemon (C. jambhiri). Differences in chloride accumulation properties between rootstocks were unrelated to rootstock vigour.

Growth, yield and fruit composition of Washington Navel and Late Valencia orange trees, as affected by rootstock and root temperature

1977 ◽  
Vol 17 (85) ◽  
pp. 336
Author(s):  
PR Cary ◽  
PGJ Weerts
Keyword(s):  
Sweet Orange ◽  
Growth Yield ◽  
Poncirus Trifoliata ◽  
The Other ◽  
Root Temperature ◽  
Rough Lemon ◽  
Washington Navel ◽  
C 30 ◽  
Increasing Temperature ◽  
Orange Trees

Wahington Navel and Late Valencia scions were budded onto three clonal rootstocks (rough lemon, sweet orange and Poncirus trifoliata) mist propagated and grown in sand. The six scion/rootstock combinations were grown in containers in a glasshouse with three root temperature treatments (19�C, 25�C, 30�C). Juvenile characteristics, evident for 5-6 years when scions are budded onto seedling rootstocks, were less marked when clonal rootstocks were used. Highest yield of fruit was produced by Late Valencia/sweet orange. This yield was 30 per cent better than previously obtained with Late Valencia grown from rooted cuttings under similar conditions. The yield from Washington Navel/sweet orange was about 30 per cent less than from Late Valencia/sweet orange; and the yields from the other scion/rootstock combinations were about 50 per cent of that from Washington Navel/ sweet orange. For most combinations more total dry matter was produced at a root temperature of 25�C than at 19�C, but there was little benefit from increasing temperature to 30�C. With either scion on rough lemon, fruit abscission was marked if root temperature treatments were imposed early (in late August). The effect was particularly severe at 25� and 30�C. Root temperature treatments for the other rootstocks were not imposed until mid-October when fruitlets were about 15 mm in diameter; under these conditions there was negligible fruit drop.

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