scholarly journals Influence of Rootstock Propagation Method on Traits of Grafted Sweet Orange Trees

HortScience ◽  
2020 ◽  
Vol 55 (5) ◽  
pp. 729-737
Author(s):  
Ute Albrecht ◽  
Shahrzad Bodaghi ◽  
Bo Meyering ◽  
Kim D. Bowman
Keyword(s):  
Tissue Culture ◽  
Tree Growth ◽  
Sweet Orange ◽  
Alternative Methods ◽  
Bacterial Disease ◽  
Trunk Diameter ◽  
Seed Supply ◽  
Nursery Production ◽  
Citrus Production ◽  
Orange Trees

The rootstock plays a large role in modern citrus production because of its influence on tolerance to adverse abiotic and biotic soil-borne stresses, and on the general horticultural characteristics of the grafted scion. In recent years, rootstock has received increased attention as a management strategy to alleviate the devastating effects of the bacterial disease huanglongbing (HLB), also known as “citrus greening.” In commercial citrus nursery production, rootstocks are typically propagated by seed. Because of the increased demand for HLB-tolerant rootstocks, seed supply is often inadequate for the most popular cultivars. Cuttings and tissue culture (TC) propagation are alternative methods to supply adequate quantities of genetically identical rootstocks to be used as liners for grafting. However, there are concerns among nursery owners and citrus growers regarding the possible inferiority of rootstocks that are not propagated by seed. This study investigates the influence of rootstock propagation method on traits of sweet orange trees grafted on four commercially important rootstock cultivars during the nursery stage and during the first year of growth in a commercial citrus orchard. Several of the measured traits during the nursery stage, including rootstock sprouting, grafted tree growth, and root mass distribution were significantly influenced by the rootstock propagation method, but traits were also influenced by the rootstock cultivar. Our results also suggest that for tissue culture-propagated plants, differences in the starting material and the culturing method can affect the grafted tree behavior. Except for canopy spread and scion to rootstock trunk diameter ratio, tree growth during the orchard stage was determined by the combination of propagation method and rootstock, rather than by propagation method alone.

scholarly journals Growth and Yield of Young ‘Valencia’ Sweet Orange Trees Treated with Insecticides

HortScience ◽  
2009 ◽  
Vol 44 (3) ◽  
pp. 686-687 ◽  
Author(s):  
Charles A. Powell ◽  
Mark A. Ritenour ◽  
Robert C. Bullock
Keyword(s):  
Sweet Orange ◽  
Control Strategies ◽  
The Other ◽  
Growth And Yield ◽  
Insect Control ◽  
Yield Data ◽  
Trunk Diameter ◽  
Marketable Fruit ◽  
Orange Trees

The trunk diameter of ‘Valencia’ sweet orange trees tested with seven insect control strategies was measured annually for the first 5 years after planting. Yield data (marketable fruit per tree) were collected after the fourth and fifth years. The insect control treatments were Admire (imidacloprid) applied at 12, 6, 3, or 2-month intervals; Temik (aldicarb) applied annually; Meta-Systox-R (oxydemeton-methyl) applied annually; or no insect control. Trunk diameter was significantly increased by Temik treatment at 1 and 2 years after planting. Six annual applications of Admire (at 2-month intervals) significantly increased trunk diameter 2 years after planting. None of the other treatments affected trunk diameters compared with the control. There were no trunk diameter differences among treatments at 3, 4, or 5 years after planting. Both Temik applied annually and Admire applied every other month or every 3 months significantly increased yield.

scholarly journals Horticultural Attributes and Root Architectures of Field-grown ‘Valencia’ Trees Grafted on Different Rootstocks Propagated by Seed, Cuttings, and Tissue Culture

HortScience ◽  
2020 ◽  
pp. 1-10
Author(s):  
Sameer Pokhrel ◽  
Bo Meyering ◽  
Kim D. Bowman ◽  
Ute Albrecht
Keyword(s):  
Tissue Culture ◽  
Root Traits ◽  
Early Years ◽  
Disease Symptoms ◽  
Trunk Diameter ◽  
Southwest Florida ◽  
Citrus Production ◽  
Propagation Methods ◽  
Production Areas ◽  
Production Losses

Huanglongbing (HLB) is a devastating disease of citrus that is found in most citrus production areas around the world. The bacterium associated with HLB resides in and damages the phloem, restricting the movement of photosynthates throughout the plant and leading to tree decline. Considerable root loss can be observed in affected trees even when few disease symptoms are visible aboveground. Root traits can substantially influence tree performance and use of superior rootstocks is one strategy to manage tree health and reduce production losses in a disease-endemic environment. Citrus rootstocks are typically propagated by seed, but due to the increased demand for some of the best-performing cultivars, propagation by other methods is being used to overcome seed shortages. In this research, differences in root architecture and root growth of six different rootstocks propagated by seed, cuttings, and tissue culture, and their influence on the grafted ‘Valencia’ (Citrus sinensis) scion were investigated. A field trial was established in southwest Florida in 2017. Trees were evaluated for their performance during the first 2 years after planting and a subset of trees was excavated for detailed analysis of root architectures and biomass distribution. Significant differences among propagation methods were found for the rootstock trunk diameter and the lateral (structural) root length, which were largest in seed-propagated rootstocks. Most of the other horticultural and root architectural traits were not significantly influenced by the rootstock-propagation method; however, many of the measured variables were significantly influenced by the rootstock cultivar regardless of the propagation method. The results showed that rootstocks propagated by cuttings and tissue culture were similar to seed-propagated rootstocks in their influence on the grafted tree during the early years of growth in the field.

Citrus Nursery Production Guide, Chapter 4: Rootstock Selection

EDIS ◽  
2019 ◽  
Vol 2019 (5) ◽  
pp. 4
Author(s):  
Ute Albrecht ◽  
Manjul Dutt ◽  
Jude Grosser
Keyword(s):  
Tissue Culture ◽  
Nursery Production ◽  
Citrus Production ◽  
The Impact

The large number of different rootstock varieties currently available for citrus production in Florida is unprecedented. This new 4-page article, chapter 4 of the forthcoming UF/IFAS Citrus Nursery Production Guide, provides information on rootstock uses in Florida, rootstock propagation, and the impact of tissue culture, as well as factors to consider when deciding which rootstock to plant. Written by Ute Albrecht, Manjul Dutt, and Jude Grosser and published by the UF/IFAS Horticultural Sciences Department. https://edis.ifas.ufl.edu/hs1340

scholarly journals Nitrogen, Calcium, and Magnesium Inconsistently Affect Tree Growth, Fruit Yield, and Juice Quality of Huanglongbing-affected Orange Trees

HortScience ◽  
2021 ◽  
pp. 1-10
Author(s):  
Eduardo Esteves ◽  
Gabriel Maltais-Landry ◽  
Flavia Zambon ◽  
Rhuanito Soranz Ferrarezi ◽  
Davie M. Kadyampakeni
Keyword(s):  
Tree Growth ◽  
Defense Mechanisms ◽  
Fruit Yield ◽  
Poncirus Trifoliata ◽  
Bacterial Disease ◽  
Juice Quality ◽  
Citrus Paradisi ◽  
Canopy Volume ◽  
Citrus Production ◽  
N Rates

The bacterial disease Huanglongbing (HLB) has drastically reduced citrus production in Florida. Nutrients play an important role in plant defense mechanisms and new approaches to manage the disease with balanced nutrition are emerging. Nutrients like nitrogen (N), calcium (Ca), and magnesium (Mg) could extend the productive life of affected trees, although interactions among these nutrients in HLB-affected citrus trees are still unclear. A 2-year study was established in Florida to determine the response of HLB-affected trees to applications of N, Ca, and Mg. The study was conducted with ‘Valencia’ trees (Citrus sinensis L. Osbeck) on Swingle citrumelo (Citrus paradisi Macf. × Poncirus trifoliata L. Raf.) rootstock on a Candler sand. Applications of N at 168, 224 (recommended rate), and 280 kg⋅ha−1 N were used as the main plots. Split-plots consisted of a grower standard treatment receiving only basal Ca (51 kg⋅ha−1) and Mg (56 kg⋅ha−1); supplemental Ca (total Ca inputs: 96 kg⋅ha−1) only; supplemental Mg (total Mg inputs: 101 kg⋅ha−1) only; and supplemental Ca (total Ca inputs: 73.5 kg⋅ha−1) and Mg (total Mg inputs: 78.5 kg⋅ha−1). The following variables were measured: tree size, fruit yield, and juice quality. Although some differences in tree growth among treatments were statistically significant (e.g., greater canopy volume with Mg fertilization at 168 kg⋅ha−1 N), there was no clear and consistent effect of plant nutrition on these variables. Fruit yield was higher with Ca and Mg relative to the grower standard at the lowest N rate in 2020, and there were no other statistically significant differences among treatments. Juice acidity was significantly higher with Mg fertilization relative to other treatments in 2019. As N rates had no significant effect in this study, unlike secondary macronutrients, N rates could potentially be reduced to 168 kg N⋅ha−1 in HLB-affected citrus without affecting vegetative growth, fruit yield, and juice quality. However, this will require optimizing the supply of secondary macronutrients and all other nutrients to develop a balanced nutritional program. Ultimately, the effects of N, Ca, and Mg obtained in this 2-year study should be confirmed with longer-term studies conducted at multiple sites.

scholarly journals 366 Nitrogen Fertigation of Young Navel Orange Trees

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 455D-455
Author(s):  
T.L. Weinert ◽  
S.A. White ◽  
T.L. Thompson ◽  
M.A. Maurer
Keyword(s):  
Best Management Practices ◽  
Management Practices ◽  
N Fertilizer ◽  
Fertilizer N ◽  
Trunk Diameter ◽  
N Partitioning ◽  
Citrus Production ◽  
Orange Trees ◽  
Leaf N ◽  
Citrus Trees

Citrus production in the southwestern U.S. is highly dependent on inputs of irrigation and N fertilizer to achieve optimum fruit yield and quality. Microsprinkler irrigation may allow for substantial increase in efficiency of N and water application. However, best management practices have not yet been developed for microsprinkler use, particularly on newly established citrus trees. Experiments were conducted during 1997–98 in central Arizona to evaluate the effects of various N rates and fertigation frequencies on growth and N partitioning in young `Newhall' navel oranges planted in Apr. 1997. Two experiments were conducted, each with factorial combinations of N rate and fertigation frequency. In one experiment, non-labeled N fertilizer was used and in the other 15N-labeled N fertilizer. Trunk diameter, leaf N, and 15N partitioning in the trees were measured. During 1997, neither trunk diameter or leaf N were affected by N rate or fertigation frequency. No more than 6% of the N applied was taken up by the trees, and about 50% of the fertilizer N taken up was found in the leaves. Trees grew much more rapidly in 1998. Leaf N in fertilized plots was significantly higher than in control plots, but leaf N in all trees remained above the critical level of 2.5%. Despite rapid tree growth during 1998, no more than 25% of the fertilizer N applied was taken up by the trees. About 60% of the fertilizer N taken up was found in the leaves. Results suggest that N applications are not needed during the first growing season after planting for microsprinkler-irrigated citrus trees in the Southwest. Only modest rates (68 to 136 g/tree) will be needed during the second season to maintain adequate tree reserves.

Using saline reclaimed water on almond grown in Mediterranean conditions: deficit irrigation strategies and salinity effects

2019 ◽  
Vol 19 (5) ◽  
pp. 1413-1421 ◽  
Author(s):  
Gaetano Alessandro Vivaldi ◽  
Salvatore Camposeo ◽  
Giuseppe Lopriore ◽  
Cristina Romero-Trigueros ◽  
Francisco Pedrero Salcedo
Keyword(s):  
Tree Growth ◽  
Deficit Irrigation ◽  
Management Practices ◽  
Water Productivity ◽  
Maximum Yield ◽  
Control Treatment ◽  
Irrigation Season ◽  
Regulated Deficit Irrigation ◽  
Trunk Diameter ◽  
Almond Trees

Abstract The main objective of this study was to acquire agronomic knowledge about the effects of irrigation with saline reclaimed (RW) and desalinated DESERT (DW) water and different irrigation strategies: control full irrigation (FI) and regulated deficit irrigation (RDI) on leaf nutrients, tree growth and fruit quality and yield of almond trees in pots. Our results showed that RW had the highest concentration of some valuable agronomic nutrients such as N, but also of phytotoxic elements (Na and Cl−). Na leaf concentration on RW treatments reached toxic levels, especially under RDI, and toxicity symptoms were shown. Regarding tree growth, cumulate trunk diameter on RW-RDI was significantly lower than on the control treatment and shoot growth was reduced from the beginning of the irrigation season in RW treatments. Maximum yield was reached on RW-FI, 18% higher than the control treatment. However, RDI strategies influenced negatively on yield, being 23% less in RW and 7% less in DW although water productivity was not significantly reduced by water stress. These findings manifest that the combination of RW and RDI can be a promising future practice for almond irrigation, but long-term studies to establish suitable management practices must be developed.

scholarly journals Highly efficient generation of canker resistant sweet orange enabled by an improved CRISPR/Cas9 system

2021 ◽  
Author(s):  
Xiaoen Huang ◽  
Nian Wang
Keyword(s):  
Genome Editing ◽  
Gene Editing ◽  
Target Genes ◽  
High Efficiency ◽  
Sweet Orange ◽  
Susceptibility Gene ◽  
Transformation Rate ◽  
Biallelic Mutation ◽  
Important Species ◽  
Citrus Production

Sweet orange (Citrus sinensis) is the most economically important species for the citrus industry. However, it is susceptible to many diseases including citrus bacterial canker caused by Xanthomonas citri subsp. citri (Xcc) that triggers devastating effects on citrus production. Conventional breeding has not met the challenge to improve disease resistance of sweet orange due to the long juvenility and other limitations. CRISPR-mediated genome editing has shown promising potentials for genetic improvements of plants. Generation of biallelic/homozygous mutants remains difficult for sweet orange due to low transformation rate, existence of heterozygous alleles for target genes and low biallelic editing efficacy using the CRISPR technology. Here, we report improvements in the CRISPR/Cas9 system for citrus gene editing. Based on the improvements we made previously (dicot codon optimized Cas9, tRNA for multiplexing, a modified sgRNA scaffold with high efficiency, CsU6 to drive sgRNA expression), we further improved our CRISPR/Cas9 system by choosing superior promoters (CmYLCV or CsUbi promoter) to drive Cas9 and optimizing culture temperature. This system was able to generate a biallelic mutation rate of up to 89% for Carrizo citrange and 79% for Hamlin sweet orange. Consequently, this system was used to generate canker resistant Hamlin sweet orange by mutating the effector binding element (EBE) of canker susceptibility gene CsLOB1, which is required for causing canker symptoms by Xcc. Six biallelic Hamlin sweet orange mutant lines in the EBE were generated. The biallelic mutants are resistant to Xcc. Biallelic mutation of the EBE region abolishes the induction of CsLOB1 by Xcc. This study represents a significant improvement in sweet orange gene editing efficacy and generating disease resistant varieties via CRISPR-mediated genome editing. This improvement in citrus genome editing makes genetic studies and manipulations of sweet orange more feasible.

scholarly journals First record of a Hop stunt viroid variant on Nagpur mandarin and Mosambi sweet orange trees on rough lemon and Rangpur lime rootstocks

2005 ◽  
Vol 54 (4) ◽  
pp. 571-571 ◽  
Author(s):  
P. Ramachandran ◽  
J. Agarwal ◽  
A. Roy ◽  
D. K. Ghosh ◽  
D. R. Das ◽  
...  
Keyword(s):  
Sweet Orange ◽  
First Record ◽  
Rangpur Lime ◽  
Stunt Viroid ◽  
Rough Lemon ◽  
Hop Stunt Viroid ◽  
Orange Trees

Effect of frequency of copper applications on control of citrus canker and the yield of young bearing sweet orange trees

2010 ◽  
Vol 29 (3) ◽  
pp. 300-305 ◽  
Author(s):  
F. Behlau ◽  
J. Belasque ◽  
J.H. Graham ◽  
R.P. Leite
Keyword(s):  
Sweet Orange ◽  
Citrus Canker ◽  
Orange Trees

scholarly journals Evaluation of New Oomycota Fungicides for Management of Phytophthora Root Rot of Citrus in California

Plant Disease ◽  
2019 ◽  
Vol 103 (4) ◽  
pp. 619-628 ◽  
Author(s):  
Wei Hao ◽  
Morgan A. Gray ◽  
Helga Förster ◽  
James E. Adaskaveg
Keyword(s):  
Root Rot ◽  
Treatment Options ◽  
Management Strategies ◽  
Resistance Management ◽  
Tree Canopy ◽  
Navel Orange ◽  
Phytophthora Root Rot ◽  
Trunk Diameter ◽  
New Compounds ◽  
Orange Trees

Phytophthora root rot, caused by several species of Phytophthora, is an important disease of citrus in California and other growing regions. For chemical management, mefenoxam and potassium phosphite have been available for many years, and resistance in Phytophthora spp. has been reported for both compounds. We evaluated the efficacy of the new Oomycota fungicides ethaboxam, fluopicolide, mandipropamid, and oxathiapiprolin, each with a different mode of action, against Phytophthora root rot of citrus in field and greenhouse studies. Root balls of navel orange trees on ‘Carrizo citrange’ rootstock were inoculated with P. nicotianae at planting in the field in fall 2013. Applications with 11 fungicide treatments were made 5 weeks after planting, in spring and fall 2014, and in spring 2015. Feeder roots and adjacent soil were collected before or after application. All of the new fungicides significantly reduced root rot incidence and Phytophthora soil populations to very low levels as compared with the control starting after the first application. Mefenoxam was only effective when a high label rate was used in the fourth application. Selected treatments also increased tree canopy size, trunk diameter, and fruit yield as compared with the control. A rate comparison with the four new fungicides was initiated in summer 2016 in another field trial using navel orange trees inoculated with P. citrophthora. Minimum effective rates to reduce Phytophthora root rot incidence and pathogen soil populations were determined after one and two applications in fall 2016 and summer 2017, respectively. Greenhouse studies confirmed the efficacy of the new fungicides. Based in part on our studies, fluopicolide recently received a federal and oxathiapiprolin a full registration for use on citrus, and registrations for ethaboxam and mandipropamid have been requested. These new compounds will provide highly effective treatment options and resistance management strategies using rotation and mixture programs for the control of Phytophthora root rot of citrus.

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