scholarly journals Forcing Treatment and Rootstock Affect Budbreak and Growth of Containerized Citrus Nursery Trees

1996 ◽  
Vol 6 (2) ◽  
pp. 134-137 ◽  
Author(s):  
J.G. Williamson ◽  
B.E. Maust
Keyword(s):  
Tree Growth ◽  
Dry Weight ◽  
Shoot Tips ◽  
Carrizo Citrange ◽  
Combination Treatments ◽  
Whole Plant ◽  
Nursery Trees ◽  
Cleopatra Mandarin ◽  
Swingle Citrumelo ◽  
The Way

Two experiments were conducted to determine the effects of rootstock and bud-forcing treatment on scion budbreak and nursery tree growth of `Hamlin' orange. In Expt. 1, `Carrizo' citrange, `Swingle' citrumelo, and `Cleopatra' mandarin were budded with `Hamlin' orange and forced by one of the following methods: cutting off (purning away the rootstock top about 2 cm above the inserted scion bud); lopping (cutting half to two-thirds of the way through the rootstock stem 2 cm above the bud union, and breaking over the stem but leaving it attached); or bending (bending the rootstock shoot above the inserted scion bud and tying it to the base of the plant). For `Swingle' only, percent budbreak was less for bending or lopping compared to cutting off. For `Carrizo' and `Swingle', scion dry weights were less when plants were forced by cutting off compared to bending or lopping. For all rootstocks, whole-plant dry weights were greater for plants forced by bending and lopping than for plants forced by cutting off. In Expt. 2, scion buds on `Swingle' and `Cleopatra' plants were forced by the three methods in Expt. 1 plus combinations of bending with notching (making an inverted V incision through the bark and into the wood on the rootstock stem directly above the scion bud) and/or topping (removing the teminal 2 cm of rootstock shoot tips of plants forced by bending). Percent scion budbreak was high for `Cleopatra' plants regardless of forcing treatment. For `Swingle', scion budbreak was greater when bending was combined with notching than for bending alone. For `Cleopatra', plant dry weight was greatest for plants forced by lopping. When bending was combined with notching, or notching with topping, `Swingle' scion budbreak was comparable to cutting off, but plant dry weights were greater with these combination treatments than when cutting off was used.

scholarly journals 930 PB 536 FORCING METHOD AND ROOTSTOCK AFFECT SCION BUDBREAK AND GROWTH OF CITRUS NURSERY TREES

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 563a-563
Author(s):  
J.G. Williamson ◽  
B.E. Maust
Keyword(s):  
Tree Growth ◽  
Citrus Sinensis ◽  
Poncirus Trifoliata ◽  
Carrizo Citrange ◽  
Whole Plant ◽  
Nursery Trees ◽  
Cleopatra Mandarin ◽  
Swingle Citrumelo

Two experiments were conducted to determine the effects of bud forcing method and rootstock on scion budbreak and nursery tree growth of `Han-din' orange (Citrus sinensis Osb.) In Expt. 1, Carrizo citrange [Citrus sinensis (L.) Osb. × Poncirus trifoliata (L.) Raf.] (Ca), Swingle citrumelo [C. paradisi (L.) Osb. × P. trifoliata (L.) Raf.] (Sw), and Cleopatra mandarin (C. reticulata Blanco) (Cl) were budded with `Hamlin' orange and forced by cutting off the rootstock tops, lopping (cutting half way through the rootstock stem above the scion bud), or bending the rootstock top and tying it to the trunk). For Cl and Ca percent budbreak was high for all forcing methods. For Sw percent budbreak was greater for cutting off than for lopping or bending. For Sw and Ca, bending or lopping resulted in greater whole plant and scion dry weights than cutting off. Expt. 2 was similar to Expt. 1 except that bending was used alone, or in combination with notching (cutting an invertal v-shaped notch above the scion bud), or with topping the bent rootstock shoot. Scion budbreak of Sw plants was greater for bending + notching than for bending alone. Other effects of rootstock and forcing method for cutting off, bending or lopping were similar to those found in Expt. 1.

scholarly journals Forcing Method and Time of Rootstock Shoot Removal Affect Growth of Containerized Citrus Nursery Trees

1997 ◽  
Vol 7 (3) ◽  
pp. 244-246
Author(s):  
J.G. Williamson
Keyword(s):  
Root Growth ◽  
Leaf Area ◽  
Tree Growth ◽  
Citrus Sinensis ◽  
Poncirus Trifoliata ◽  
Removal Time ◽  
Whole Plant ◽  
Nursery Trees ◽  
Shoot Removal ◽  
Cleopatra Mandarin

I conducted an experiment to determine the effects of time of rootstock shoot removal on growth of citrus nursery plants forced by bending and lopping. `Hamlin' orange [Citrus sinensis (L.) Osb.] budded on Carrizo citrange [C. sinensis (L.) × Poncirus trifoliata (L.) Raf.] and Cleopatra mandarin (C. reticulata Blanco) seedlings were grown in 2.8-L plastic pots and forced by bending or lopping the rootstock shoots. For Carrizo plants, rootstock shoots were removed 0, 21, 36, 170, or 235 days after forcing. For Cleopatra plants, rootstock shoots were removed 0, 11, 21, 36, 170, and 235 days after forcing. Bending and lopping with rootstock shoots remaining attached for 36 days after forcing resulted in greater nursery tree growth (scion, root, and wholeplant dry masses; scion length; and leaf area) than when rootstock shoots were removed the day of forcing. Growth of scion leaves (both rootstocks) and stems (Cleopatra) was greatest at a rootstock shoot removal time (RSRT) of 36 days after forcing. However, root and whole plant dry masses increased as RSRT increased up to 235 days after forcing. These results suggest that roots continue to be a major sink for rootstock photosynthates of bent or lopped plants during periods after the first scion growth flush. Proportionally greater root growth occurred on plants forced by bending or lopping when rootstock shoots were left attached for more than the usual 4 to 5 weeks after forcing.

scholarly journals Growth of Budded, Containerized, Citrus Nursery Plants when Photosynthesis of Rootstock Shoots Is Limited

HortScience ◽  
1995 ◽  
Vol 30 (7) ◽  
pp. 1363-1365 ◽  
Author(s):  
J.G. Williamson ◽  
B.E. Maust
Keyword(s):  
Primary Source ◽  
Poncirus Trifoliata ◽  
Photon Flux ◽  
Citrus Reticulata ◽  
Growth Responses ◽  
Photosynthetic Photon Flux ◽  
Whole Plant ◽  
Nursery Trees ◽  
Cleopatra Mandarin ◽  
Swingle Citrumelo

Two experiments were conducted to determine the effects of rootstock shoot defoliation or shading on growth during the first two scion flushes of budded, containerized, citrus nursery trees. Both experiments were conducted in a greenhouse with Cleopatra mandarin (Citrus reticulata Blanco) and Swingle citrumelo [C. paradisi (L.) Osb. × Poncirus trifoliata (L.) Raf.] seedlings budded with `Hamlin' orange [C. sinensis (L.) Osb.]. Scion buds were forced by cutting off the rootstock shoots above the bud union or by bending the rootstock shoots and tying them to the base of the plants (bending). In one experiment, shoots from both rootstocks that were forced by bending received one of four defoliation treatments: treatments were 0%, 40%, 60%, or 85% (based on leaf area) defoliation for Cleopatra and 0%, 30%, 60%, or 100% defoliation for Swingle. In the second experiment, rootstock shoots of plants forced by bending were subjected to a maximum photosynthetic photon flux (PPF) of 820, 225, 90, or 30 μmol·m–2·s–1. Growth of Cleopatra plants declined linearly with increasing levels of rootstock shoot defoliation. When rootstock shoot defoliation was ≤40%, whole-plant (minus rootstock shoot) dry weights were higher for plants forced by bending than for those forced by cutting off rootstock shoots. For Swingle, most growth responses to rootstock shoot defoliation were curvilinear. Higher levels of rootstock shoot defoliation resulted in less growth than lower defoliation levels. Low PPF reduced whole-plant (minus rootstock shoot) and root dry weights for both rootstocks compared to high PPF. For Cleopatra, whole-plant and scion dry weights were highest at the highest PPF. For Swingle, whole-plant and scion dry weights were highest at 225 μmol·m–2·s–1. For both rootstocks, plants forced by bending had higher dry weights at 820 and 225 μmol·m–2·s–1 than plants forced by cutting off the rootstock shoots. For Swingle, most of the reduction in scion growth from rootstock shoot defoliation occurred during the first scion flush. Our results suggest that recently produced rootstock shoot photosynthates are the primary source of greater plant growth achieved by bending compared to cutting off rootstock shoots.

scholarly journals (330) Growth and Nutritional Response of Six Citrus Rootstocks to Increasing Levels of Copper

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1066A-1066
Author(s):  
Joseph Albano ◽  
Kim Bowman
Keyword(s):  
Nutrient Solution ◽  
Poncirus Trifoliata ◽  
Citrus Groves ◽  
Whole Plant ◽  
Volkamer Lemon ◽  
Florida Citrus ◽  
Cleopatra Mandarin ◽  
Swingle Citrumelo

Nutrient disorders related to excessive levels of copper in soils are common in Florida citrus groves that have been under production for many years, mainly due to the continual use of copper-containing pesticides. The objectives of the study were to investigate the growth and nutritional response of six citrus rootstocks (nonbudded) grown in 4-L containers in sand to increasing concentrations of copper. The rootstocks included: Swingle citrumelo (Citrusparadisi Macf. × Poncirus trifoliata [L.] Raf.), Volkamer lemon (C. volkameriana Ten. and Pasq.), Cleopatra mandarin (Citrusreticulata Blanco), Flying Dragon (P. trifoliata); and two new USDA series rootstocks, US-812 (Sunki mandarin × P. trifoliata released in 2001), and US-897 (a hybrid of Cleopatra × Flying Dragon not yet released). Copper was supplied at 0.05, 0.25, 1.00, and 2.00 mg·L-1 CuEDTA incorporated into a modified Hoagland's nutrient solution. As a mean of all Cu treatments, whole plant Cu levels (μg·g-1) were: Flying Dragon, 17.33; US-897, 21.68; Cleopatra, 27.33; US-812, 28.84; Swingle, 29.74; and Volkamer, 34.05. As a mean of all Cu treatments, foliar Cu levels (μg·g-1) were greatest and least in US-812 (7.74) and Cleopatra (4.05), respectively; and root Cu levels (μg·g-1) were greatest and least in Volkamer (61.08) and Flying Dragon (30.08), respectively.

scholarly journals Growth and 14C-Photosynthate Allocation in Citrus Nursery Trees Subjected to One of Three Bud-forcing Methods

1992 ◽  
Vol 117 (1) ◽  
pp. 37-40 ◽  
Author(s):  
J.G. Williamson ◽  
W.S. Castle ◽  
K.E. Koch
Keyword(s):  
Leaf Area ◽  
Citrus Sinensis ◽  
Dry Weight ◽  
Poncirus Trifoliata ◽  
Plant Parts ◽  
Whole Plant ◽  
Weight Analysis ◽  
Bud Growth ◽  
Nursery Trees ◽  
Photosynthate Allocation

Three commercially employed treatments to force scion bud growth were compared using greenhouse-grown `Carrizo' citrange [Citrus sinensis (L.) Osb. × Poncirus trifoliata (L.) Raf.] seedlings budded with `Hamlin' orange [Citrus sinensis (L.) Osb.]. Scion buds were forced either by 1) cutting off (removing the rootstock shoot above the bud union); 2) lopping (cutting half-way through the rootstock shoot above the bud union and breaking over the rootstock stem); or 3) bending (bending the rootstock shoot to its base and tying it in position). Plants were harvested, dried, and weighed at various times after scion shoot emergence. Plants on which rootstock shoots remained attached (lopping or bending) had the largest scion leaf area and gained the most scion and whole-plant dry weight. Bending rootstock shoots also resulted in a longer scion, more leaves, and higher root dry weight than did removal of rootstock shoots by cutting off. Few differences in overall growth were observed among trees retaining their rootstock shoots after two scion growth flushes. Removal of rootstock shoots after the first scion growth flush reduced leaf area and dry weight gain of the second scion growth flush; however, it did not affect total scion leaf area or dry weight. Analysis of 14C-photosynthate transfer from labeled rootstock leaves showed that bending allowed the greatest movement of labeled assimilates to other plant parts during the 24 hours after 14CO2 fixation. Radiolabeled photosynthates from rootstock leaves were partitioned primarily to shoots during scion growth flushes and to roots during periods between growth flushes.

scholarly journals Performance of `Ambersweet' Orange Trees on Cleopatra Mandarin and Swingle Citrumelo Rootstocks

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 664d-664
Author(s):  
Mongi Zekri
Keyword(s):  
Fruit Quality ◽  
Tree Growth ◽  
Growth Yield ◽  
Fruit Production ◽  
Soluble Solids ◽  
Consistent Difference ◽  
Juice Quality ◽  
Mineral Concentration ◽  
Cleopatra Mandarin ◽  
Swingle Citrumelo

Because of the many concerns about fruit quality and fruit production of `Ambersweet' cultivar, this study was conducted in Florida to evaluate the performance of this cultivar budded on two rootstocks and grown in three locations. The effects of Cleopatra mandarin (CM) rootstock on tree growth, yield, fruit quality, and leaf mineral concentration were compared to those of Swingle citrumelo (SC). Although tree shape differed with the rootstock, no consistent difference was found in tree growth between the two rootstocks. Significant differences in yield, fruit size, and fruit quality were found between the two rootstocks. Fruit produced on CM were large with a rough, thick peel and poor color. Swingle citrumelo rootstock promoted higher yield and better fruit and juice quality than CM. Earlier fruit maturity and higher soluble solids and juice content were obtained from trees grown on the Flatwoods compared to trees grown on the central ridge. With the exception of magnesium, no consistent difference in leaf mineral concentration was found between the two rootstocks.

scholarly journals Nitrogen Nutrition and Growth of `Hamlin' Orange Nursery Trees on Swingle' Citrumelo Rootstock

1995 ◽  
Vol 5 (2) ◽  
pp. 147-149 ◽  
Author(s):  
Laura Guazzelli ◽  
Frederick S. Davies ◽  
James J. Ferguson ◽  
William S. Castle
Keyword(s):  
Nitrogen Nutrition ◽  
Dry Weight ◽  
Poncirus Trifoliata ◽  
Trunk Diameter ◽  
Commercial Media ◽  
Nursery Trees ◽  
Orange Trees ◽  
Leaf Dry Weight ◽  
Swingle Citrumelo ◽  
Level Analysis

Two experiments were conducted with container-grown `Hamlin' orange trees [Citrus sinensis (L.) Osb.] on `Swingle' citrumelo [C. paradisi Macf. × Poncirus trifoliata (L.) Raf.] rootstock to study the effects of N rate on plant growth in the nursery. Treatments consisted of 12, 50, 100, or 200 mg N/liter per tree applied once a week by drip irrigation. Commercial media was used and soil water content was maintained at container capacity. In Expt. 1, fertilization at 200 mg·liter−1 resulted in greater scion growth, trunk diameter, and total leaf dry weight compared to the other rates. In Expt. 2, fertilization at 100 and 200 mg·liter−1 resulted in greater scion growth,” trunk diameter, and leaf and stem dry weights compared to lower rates, but no differences were observed between the two highest rates. Trees that received 12 and 50 mg·liter−1 were stunted and leaves were chlorotic. Therefore, the optimum calculated N rate for `Hamlin' nursery trees on `Swingle' citrumelo rootstock, based on critical level analysis, is 155 to 165 mg·liter-1.

scholarly journals Elevated CO2 Increases Growth and Photosynthetic Efficiency of Citrus Rootstock Seedlings

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 531B-531
Author(s):  
J.P. Syvertsen
Keyword(s):  
Water Use ◽  
Plant Size ◽  
Single Leaf ◽  
Plant Water Use ◽  
Whole Plant ◽  
Volkamer Lemon ◽  
Citrus Rootstock ◽  
Use Efficiency ◽  
Cleopatra Mandarin ◽  
Swingle Citrumelo

The objectives of these greenhouse experiments were to determine the effects of elevated CO2 on growth, mineral nutrition, and gas exchange physiology of seedlings of four commercial Citrus rootstocks. We grew well-watered and fertilized seedlings of `Volkamer' lemon (VL), `Cleopatra' mandarin (CL), `Swingle' citrumelo (SW), and `Troyer' citrange (TC) cultivars (in decreasing order of vigor) in unshaded, air-conditioned greenhouses at ambient CO2 (350 μmol/mol) or 2x ambient CO2 for 5 months. CL was the smallest cultivar, had the lowest root/shoot (r/s) ratio,and lowest rates of CO2 assimilation (A) of leaves, transpiration (E), and water-use efficiency, (A/E). Overall, daily whole-plant water use was correlated with single-leaf E. Elevated CO2 increased both shoot and root growth similarly; therefore, r/s was not affected. Elevated CO2 increased A, leaf dry wt/area, and leaf C, but decreased transpiration and leaf N so that leaf C/N, A/N, and A/E all increased. Although plant size of the four cultivars ranked similarly at both ambient and high CO2, the more-vigorous cultivars grew proportionately more at high CO2 than the less-vigorous cultivars. Growing cultivars at elevated CO2 can yield insights into mechanisms determining vigor and relationships between A and plant growth.

scholarly journals Protection of Citrus Rootstocks Against Phytophthora spp. with a Hypovirulent Isolate of Phytophthora nicotianae

2007 ◽  
Vol 97 (8) ◽  
pp. 958-963 ◽  
Author(s):  
G. C. Colburn ◽  
J. H. Graham
Keyword(s):  
Poncirus Trifoliata ◽  
Phytophthora Nicotianae ◽  
Root Weight ◽  
Post Inoculation ◽  
Phytophthora Root Rot ◽  
Phytophthora Spp ◽  
Naturally Occurring ◽  
Fibrous Roots ◽  
Cleopatra Mandarin ◽  
Swingle Citrumelo

Phytophthora root rot of citrus in Florida is caused by Phytophthora nicotianae and P. palmivora. A naturally occurring isolate of P. nicotianae (Pn117) was characterized as hypovirulent on citrus roots. Pn117 infected and colonized fibrous roots, but caused significantly less disease than the virulent isolates P. nicotianae Pn198 and P. palmivora Pp99. Coincident inoculation of rootstock seedlings of Cleopatra mandarin (Citrus reticulata) or Swingle citrumelo (C. paradisi × Poncirus trifoliata) with the hypovirulent Pn117 and the virulent isolates Pn198 and Pp99 did not reduce the severity of disease caused by the virulent Phytophthora spp. When either rootstock was inoculated with the hypovirulent Pn117 for 3 days prior to inoculation with virulent isolates, preinoculated seedlings had significantly less disease and greater root weight compared with seedlings inoculated with the virulent isolates alone. Recovery of the different colony types of Phytophthora spp. from roots of sweet orange (C. sinensis) or Swingle citrumelo was evaluated on semiselective medium after sequential inoculations with the hypovirulent Pn117 and virulent Pp99. Pn117 was isolated from roots at the same level as the Pp99 at 3 days post inoculation. Preinoculation of Pn117 for 3 days followed by inoculation with Pp99 resulted in greater recovery of the hypovirulent isolate and lower recovery of the virulent compared with coincident inoculation.

scholarly journals Fuel manipulation with herbicide treatments to reduce fire hazard in young pine (Pinus elliottii × P. caribaea) plantations in south-east Queensland, Australia

2012 ◽  
Vol 21 (8) ◽  
pp. 992 ◽  
Author(s):  
Tom Lewis ◽  
Joanne De Faveri
Keyword(s):  
Adverse Effects ◽  
Tree Growth ◽  
Prescribed Fire ◽  
Fire Hazard ◽  
Dry Weight ◽  
Pinus Elliottii ◽  
Pine Plantations ◽  
Prescribed Burns ◽  
Standing Biomass ◽  
Herbicide Treatments

Wildfire represents a major risk to pine plantations. This risk is particularly great for young plantations (generally less than 10 m in height) where prescribed fire cannot be used to manipulate fuel biomass, and where flammable grasses are abundant in the understorey. We report results from a replicated field experiment designed to determine the effects of two rates of glyphosate (450 g L–1) application, two extents of application (inter-row only and inter-row and row) with applications being applied once or twice, on understorey fine fuel biomass, fuel structure and composition in south-east Queensland, Australia. Two herbicide applications (~9 months apart) were more effective than a once-off treatment for reducing standing biomass, grass continuity, grass height, percentage grass dry weight and the density of shrubs. In addition, the 6-L ha–1 rate of application was more effective than the 3-L ha–1 rate of application in periodically reducing grass continuity and shrub density in the inter-rows and in reducing standing biomass in the tree rows, and application in the inter-rows and rows significantly reduced shrub density relative to the inter-row-only application. Herbicide treatment in the inter-rows and rows is likely to be useful for managing fuels before prescribed fire in young pine plantations because such treatment minimised tree scorch height during prescribed burns. Further, herbicide treatments had no adverse effects on plantation trees, and in some cases tree growth was enhanced by treatments. However, the effectiveness of herbicide treatments in reducing the risk of tree damage or mortality under wildfire conditions remains untested.

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