scholarly journals Apparent Nucleation and Freezing in Various Parts of Young Citrus Trees during Controlled Freezes

HortScience ◽  
1991 ◽  
Vol 26 (5) ◽  
pp. 576-579 ◽  
Author(s):  
George Yelenosky
Keyword(s):  
Tissue Damage ◽  
Citrus Sinensis ◽  
Sweet Orange ◽  
Rapid Progression ◽  
Rough Lemon ◽  
Initial Freezing ◽  
Orange Trees ◽  
Soil Level ◽  
Citrus Trees

One- to 4-year-old sweet orange trees, Citrus sinensis (L.) Osbeck cv. Valencia on rough lemon (C. jambhiri Lush.) rootstock, were used in a series of tests on the depth and stability of supercooling in various parts of greenhouse-grown trees held in pots during controlled freezes. Thermocouples were attached to flowers, fruit, leaves, and wood. Supercooling levels were inconsistent, ranging from – 3C to – 7C. Nucleation was spontaneous and well defined by sharp exotherms. Rapid progression of crystallization (≈ 60 cm·min–1) indicated no major obstacles to ice propagation throughout the tree above soil level. The site of initial freezing was variable, with a tendency for trees to freeze from the base of the stem toward the top. The location of tissue damage did not necessarily correspond to the location of initial freeze event. Freezing in the wood often preceded freezing of flowers.

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

Accumulation and Metabolism of Bromacil in Pineapple Sweet Orange (Citrus sinensis) and Cleopatra Mandarin (Citrus reticulata)

Weed Science ◽  
1981 ◽  
Vol 29 (1) ◽  
pp. 1-4 ◽  
Author(s):  
L. S. Jordan ◽  
W. A. Clerx
Keyword(s):  
Citrus Sinensis ◽  
Sweet Orange ◽  
Citrus Reticulata ◽  
Minor Metabolite ◽  
A Minor ◽  
Orange Trees ◽  
Conjugated Metabolites ◽  
Cleopatra Mandarin

Young orange [Citrus sinensis (L.) Osbeck ‘Pineapple sweet orange’] trees are more sensitive to bromacil (5-bromo-3-sec-butyl-6-methyluracil) than young mandarin (Citrus reticulata Blanco ‘Cleopatra mandarin’) trees. Pineapple sweet orange roots absorbed twice as much 14C from bromacil, and accumulated three times as much in the leaves, as did Cleopatra mandarin. The amount of conjugated metabolites formed was the same in the roots of the two cultivars, but twice as much formed in the leaves of Cleopatra mandarin as in the leaves of Pineapple sweet orange. The principle metabolite was 5-bromo-3-sec-butyl-6-hydroxymethyluracil; a minor metabolite was tentatively identified as 5-bromo-3-(3-hydroxyl-1-methylpropyl)-6-methyluracil. No 5-bromouracil was detected. Citrus cultivars differ in their ability to accumulate and metabolize bromacil into conjugated nonphytotoxic compounds.

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.

scholarly journals Performance of the pineapple sweet orange on different rootstocks

2020 ◽  
Vol 36 (2) ◽  
Author(s):  
Carlos Roberto Martins ◽  
Hélio Wilson Lemos de Carvalho ◽  
Adenir Vieira Teodoro ◽  
Inácio de Barros ◽  
Luciana Marques de Carvalho ◽  
...  
Keyword(s):  
Sweet Orange ◽  
Chemical Quality ◽  
Santa Cruz ◽  
Rangpur Lime ◽  
Rough Lemon ◽  
Physico Chemical ◽  
High Regularity ◽  
Orange Trees ◽  
Swingle Citrumelo

This study aimed at evaluating the agronomical performance of ‘Pineapple’ sweet orange grafted on ten rootstocks, in 2011-2017 harvests, so as to recommend the best combinations to be commercially explored in citrus growing regions in Bahia and Sergipe states, Brazil. An experiment was installed to test ten rootstock for 'pineapple' sweet orange: 'Santa Cruz' Rangpur lime, 'Red Rough' Lemon, 'Orlando' Tangelo, 'Sunki Tropical' Mandarin, 'Swingle' citrumelo, the citrandarins 'Indio' and 'Riverside' and the hybrids HTR-051, LVKxLCR-010 and TSKxCTTR-002. The trial was installed in 2008 in the municipality of Umbauba in Sergipe. The experimental design was complete randomized blocks with four replications and two plants per plot. Plant spacing was 6 x 4 m which corresponds to 416 plants per hectare and the orchard was rainfed and followed conventional management. The following agronomical parameters were evaluated: vegetative growth, drought tolerance, yield and physico-chemical quality of fruits as well as the abundance of phytophagous mites. Both hybrids LVK x LCR – 010 and TSKC x CTTR-002 and the ‘Santa Cruz’ rangpur lime bestowed higher tolerance to the dry period on the ‘Pineapple’ orange tree, by comparison with higher water deficit susceptibility conferred by the ‘Orlando’ tangelo and the ‘Swingle’ citrumelo. Rootstocks HTR-051, ‘Riverside’ citrandarin, ‘Swingle’ citrumelo and TSKC x CTTR-02 induced plants to remain small and, thus, showed aptitude for culture densification. Cumulative yield of the ‘Pineapple’ orange was higher on rootstocks ‘Red Rough’ lemon and ‘Santa Cruz’ Rangpur lime, the hybrid LVK x LCR-010 and ‘Sunki Tropical’. Yield efficiency was not influenced by the rootstocks. Physico-chemical quality of fruits of ‘Pineapple’ orange is affected by the rootstocks and meets the requirements of juice industries. Regarding plant resistance, the rootstocks did not influence the population density of mites P. oleivora, E. banksi and T. mexicanus on ‘Pineapple’ oranges. Results show that both rootstocks ‘Red Rough’ lemon and ‘Santa Cruz’ rangpur lime conferred high regularity to ‘Pineapple’ orange trees in citrus growing regions in Bahia and Sergipe states.

scholarly journals Uptake Patterns of 11 Elements of Orange Trees in Solution Culture

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 486B-486
Author(s):  
H.K. Wutscher
Keyword(s):  
Nutrient Solution ◽  
Citrus Sinensis ◽  
Soil Extract ◽  
Solution Culture ◽  
Field Soil ◽  
Rough Lemon ◽  
Valencia Orange ◽  
Orange Trees ◽  
Solution Change ◽  
Complete Nutrient Solution

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.

Effect of cultural practices on the manganese status of soil and citrus trees under irrigation.

1954 ◽  
Vol 5 (1) ◽  
pp. 31 ◽  
Author(s):  
J Connor
Keyword(s):  
Ammonium Sulphate ◽  
Soil Ph ◽  
Cultural Practices ◽  
Sweet Orange ◽  
Manganese Deficiency ◽  
Irrigation Area ◽  
Visual Symptoms ◽  
Deficiency Symptoms ◽  
Rough Lemon ◽  
Citrus Trees

The occurrence of manganese deficiency in citrus on an experimental orchard established in light horticultural soil in the Murrumbidgee Irrigation Area is reported. There is a relationship between visual symptoms of deficiency and the amount of manganese in the leaf. When the leaf manganese falls to 20 p.p.m., 50 per cent. of the trees show visual deficiency symptoms. Trees on Sweet Orange stock had less manganese and showed more visual deficiency symptoms than trees on Rough Lemon stock. A decrease in soil pH consequent on the addition of ammonium sulphate fertilizer led to a graduated increase in exchangeable soil manganese and leaf manganese. Bringing the calcareous subsoil to the surface consequent on digging trenches for laying agricultural drains led to acute manganese deficiency. Trees on plots tilled during the summer have greater leaf manganese contents than trees on sod plots or plots not tilled but kept free of weeds by herbicidal sprays, but these cultural treatments do not affect the exchangeable soil manganese. Possible reasons for the differences are discussed.

scholarly journals Ground Application of Overdoses of Manganese Have a Therapeutic Effect on Sweet Orange Trees Infected with Candidatus Liberibacter asiaticus

HortScience ◽  
2019 ◽  
Vol 54 (6) ◽  
pp. 1077-1086 ◽  
Author(s):  
Flavia T. Zambon ◽  
Davie M. Kadyampakeni ◽  
Jude W. Grosser
Keyword(s):  
Therapeutic Effect ◽  
Sweet Orange ◽  
Quantitative Polymerase Chain Reaction ◽  
Therapeutic Effects ◽  
Tree Health ◽  
Rough Lemon ◽  
Canopy Volume ◽  
Liberibacter Asiaticus ◽  
Root Health ◽  
Orange Trees

There is accumulating evidence that root system collapse is a primary symptom associated with Huanglongbing (HLB)-induced tree decline, especially for commercial sweet orange and grapefruit trees on Swingle and Carrizo rootstocks. Maintaining root health is imperative to keep trees productive in an HLB-endemic environment. Preliminary greenhouse and field studies have shown that HLB-impacted trees had secondary and micronutrient deficiencies that were much greater in the roots than in the leaves, and that treatments containing three-times the recommended dose of manganese (Mn) improved tree health and growth and increased feeder root density in greenhouse trees. These results suggested that trees in an HLB-endemic environment have higher specific micronutrient requirements than those currently recommended. To test this hypothesis, established Vernia sweet orange grafted onto rough lemon rootstock trees were divided into eight supplemental CRF nutrition treatments (including two-times and four-times the recommended doses of Mn and boron) using a randomized complete block design in a commercial grove in St. Cloud, FL. The following supplemental nutrition treatments were used: no extra nutrition (control); Harrell’s–St. Helena mix 0.9 kg per tree; Harrell’s with 32 g of Florikan polycoated sodium borate (PSB) per tree; Harrell’s with 90 g of TigerSul® Mn sulfate (MS) per tree; Harrell’s with 32 g of PSB and 90 g of MS per tree; 180 g of MS per tree; 64 g of PSB per tree; and 180 g of MS plus 64 g of PSB per tree applied every 6 months since Fall 2015. Leaf and soil nutritional analyses were performed in Mar. 2017, Sept. 2017, and May 2018; a quantitative polymerase chain reaction was performed for Candidatus Liberibacter asiaticus (CLas) titer estimation in Nov. 2017. Significantly higher cycle threshold (Ct) values indicating reduced CLas bacterial populations were observed in trees that received the higher doses of Mn, especially those receiving four-times the recommended dosage of Mn (180 g Mn). Many trees exhibited Ct values of 32 or more, indicating a nonactive infection. Fruit yields of these trees were also increased. No significant differences in juice characteristics, canopy volume, and trunk section area were found between control plants and plants treated with 180 g Mn. Soil and leaf nutrients B, K, Mn, and Zn were significantly different among treatments at various times during the study. Our results strongly suggest that overdoses of Mn can suppress CLas bacterial titers in sweet orange trees on rough lemon rootstock, thus providing a therapeutic effect that can help restore tree health and fruit yields. This response was not observed when Mn and B were combined in the overdose, suggesting an antagonistic effect from B on Mn metabolism. When an overdose of Mn is used, biological functions and tree tolerance lost due to nutritional imbalances caused by HLB might be restored. Further studies are needed to elucidate which metabolic pathways are altered by comparing overdosed and conventionally fertilized HLB-impacted trees and to determine if the observed therapeutic effects can be achieved in trees grafted to other important commercial rootstocks.

scholarly journals Survival of Young Cold-hardened `Hamlin' Orange Trees at – 6.7C

HortScience ◽  
1990 ◽  
Vol 25 (1) ◽  
pp. 98-99 ◽  
Author(s):  
George Yelenosky
Keyword(s):  
Oxygen Uptake ◽  
Citrus Sinensis ◽  
Photon Flux ◽  
Controlled Environment ◽  
Photosynthetic Photon Flux ◽  
Test Room ◽  
Rough Lemon ◽  
Tree Survival ◽  
Freeze Test ◽  
Orange Trees

Potted greenhouse-grown, l-year-old `Hamlin' orange [Citrus sinensis (L.) Osbeck] trees on 1.5-year-old rough lemon (C. jambhiri Lush.) rootstock were temperature-conditioned for 6 consecutive weeks in a controlled-environment room to test cold-hardening ability. Holding at 15.6 ± 0.6C during 12-hr days [425 μmol·s-1·m-2 photosynthetic photon flux (PPF) at top of trees] and 4.4C during nights resulted in 100% tree survival and no leaf loss “after 4 hr of – 6.7C in a dark freeze test room. Unhardened greenhouse trees were killed to rootstock. Solute efflux (dS·m-1) from unhardened frozen leaves was > 20-fold that from frozen leaves on hardened trees and nonfrozen leaves on unhardened trees. Oxygen uptake was not significantly impaired in frozen hardened leaves. No 02 uptake was evident for frozen unhardened leaves.

The use of gibberellic acid to control alternate cropping of Late Valencia sweet orange

1977 ◽  
Vol 28 (6) ◽  
pp. 1041 ◽  
Author(s):  
GI Moss ◽  
KB Bevington
Keyword(s):  
Gibberellic Acid ◽  
Sweet Orange ◽  
Poncirus Trifoliata ◽  
Minimum Concentration ◽  
Rough Lemon ◽  
Small Fruit ◽  
Valencia Orange ◽  
Orange Trees ◽  
Long Term Adverse Effects

The effect of spraying commercial gibberellic acid (GA) on alternate cropping and yield of Late Valencia orange trees was studied in detail at three sites over three seasons. Two applications of GA were applied at a minimum concentration of 25 ppm (in two experiments 0.75% emulsifiable oil was used as an adjuvant) 3 weeks apart during April and May for Dareton (on the River Murray) or June and early July for Yanco (Murrumbidgee Irrigation Areas) prior to the heavy-crop blossom. These sprays partly inhibited flowering and the subsequent heavy crop was reduced by up to 22% (by fruit number). In the next season there were more flowers and the light crop was increased by up to 57% at Dareton and 228% at Yanco. Some treatments practically eliminated alternate cropping while all reduced considerably the heavyllight crop ratio. Mean weight yields over 2 years were increased by up to 17% at Yanco and 16% at Dareton with mean increases for all successful GA treatments of 12.6% and 7.2% respectively. This represented an increase of 34 and 24 kg fruitltree. No long-term adverse effects on yield were found.Apart from re-greening of the fruit present at the time of spraying, fruit quality was not affected. There were fewer non-saleable small fruit at Yanco in the heavy crop as a result of the GA treatments, and a better range of fruit sizes in both the heavy and light crops. Trees on Rough Lemon rootstock responded well to GA treatments, especially in terms of increased yield in the light crop. Poncirus trifoliata rootstock was less responsive than Sweet Orange. This method might be used for the commercial control of alternate cropping of Late Valencia orange trees.

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