scholarly journals Fruit abscission pattern of ‘Valencia’ orange with canopy shaker system

2019 ◽  
Vol 246 ◽  
pp. 916-920 ◽  
Author(s):  
Fernando Aragon-Rodriguez ◽  
Sergio Castro-Garcia ◽  
Rafael Rubén Sola-Guirado ◽  
Jesús A. Gil-Ribes
Keyword(s):  
Fruit Abscission ◽  
Valencia Orange ◽  
Canopy Shaker

scholarly journals Fruit Abscission and Leaf Drop in Citrus Cultivars Treated with Metsulfuron-methyl

1999 ◽  
Vol 9 (3) ◽  
pp. 412-416 ◽  
Author(s):  
Walter J. Kender ◽  
Ulrich Hartmond ◽  
Jacqueline K. Burns
Keyword(s):  
Active Ingredient ◽  
Citrus Sinensis ◽  
Citrus Fruit ◽  
Fruit Abscission ◽  
Metsulfuron Methyl ◽  
Fruit Drop ◽  
Valencia Orange ◽  
Leaf Drop

Fruit of 11 citrus cultivars were evaluated for their response to the experimental abscission material metsulfuron-methyl at 2 mg·L-1 (ppm) active ingredient as an aid to mechanical or hand harvest. Cultivars evaluated included `Ambersweet', `Glen Navel', `Hamlin', and `Valencia' oranges [Citrus sinensis (L.) Osb.], `Robinson' tangerine (Clementine × Orlando, C. reticulata Blanco), `Sunburst' tangerine [`Robinson' × `Osceola', C. reticulata × (C. paradisi Macf. × C. reticulata)], `Murcott' and `Temple' tangor (C. reticulata × C. sinensis), `Orlando' tangelo (C. reticulata × C. paradisi), `Ray Ruby', and `Marsh' grapefruit (C. paradisi). Six of the 11 cultivars were effectively loosened by sprays of metsulfuron-methyl (`Hamlin', `Valencia', `Orlando', `Murcott', `Temple', and `Ray Ruby'). Addition of an adjuvant (Kinetic, 0.125%) was necessary for abscission activity in fruit and leaves. Trees sprayed with metsulfuron-methyl in combination with an adjuvant had higher percent cumulative fruit drop, higher internal ethylene, and lower fruit detachment forces (FDF) than trees sprayed with metsulfuron-methyl alone. `Sunburst' tangerine responded poorly to the abscission material in the presence or absence of Kinetic. Leaf loss was greatest in trees sprayed with metsulfuron-methyl and adjuvant, intermediate in trees sprayed with metsulfuron-methyl alone, and least in control trees. Twig dieback was observed in trees of `Valencia' orange and `Marsh' grapefruit sprayed with metsulfuron-methyl. The peel of some cultivars had irregular coloration and developed pitted areas after harvest. Although metsulfuron-methyl is an effective abscission agent for mature citrus fruit, further work is needed to more accurately define conditions for its safe and dependable use.

scholarly journals Naphthalene Acetic Acid and 2,3,5-triiodobenzoic Acid Affect the Response of Mature Orange Fruit to Abscission Chemicals

HortScience ◽  
2002 ◽  
Vol 37 (2) ◽  
pp. 348-352 ◽  
Author(s):  
Rongcai Yuan ◽  
Ulrich Hartmond ◽  
Walter J. Kender
Keyword(s):  
Acetic Acid ◽  
Abscission Zone ◽  
Naphthalene Acetic Acid ◽  
Mature Fruit ◽  
Fruit Abscission ◽  
Triiodobenzoic Acid ◽  
Valencia Orange ◽  
Auxin Concentration ◽  
Auxin Transport Inhibitor ◽  
Orange Fruit

Effects of NAA, TIBA, ethephon, and CMN-Pyrazole on fruit detachment force (FDF) of mature `Valencia' and `Hamlin' orange [Citrus sinensis (L.) Osb.] fruit were examined in 2000 and 2001. NAA effectively inhibited the reduction in FDF or fruit abscission caused by ethephon when applied to the abscission zone 24 hours before ethephon application, but had no significant effect when applied to the fruit without contacting the abscission zone, or to the peduncle ≈4 cm above the abscission zone. TIBA, an auxin transport inhibitor, decreased FDF of mature fruit and promoted fruit abscission when applied alone as a spray to the canopy or directly to the fruit peduncle. This response was dependent on TIBA concentration. TIBA was more effective when applied in combination with ethephon or CMN-Pyrazole than alone. These results are consistent with our previous data that endogenous auxin concentration in the abscission zone of mature `Valencia' orange fruit is one of the factors controlling the sensitivity and thus the responsiveness of the abscission zone of mature fruit to abscission chemicals. Chemical names used: 5-chloro-3-methyl-4-nitro-pyrazole (CMN-Pyrazole); 2-chloroethylphosphonic acid (ethephon); naphthalene acetic acid (NAA); 2,3,5-triiodobenzoic acid (TIBA).

scholarly journals Young Fruit and Auxin Transport Inhibitors Affect the Response of Mature `Valencia' Oranges to Abscission Materials via Changing Endogenous Plant Hormones

2003 ◽  
Vol 128 (3) ◽  
pp. 302-308 ◽  
Author(s):  
Rongcai Yuan ◽  
Walter J. Kender ◽  
Jacqueline K. Burns
Keyword(s):  
Auxin Transport ◽  
Abscission Zone ◽  
Mature Fruit ◽  
Young Fruit ◽  
Fruit Abscission ◽  
Endogenous Plant Hormones ◽  
Valencia Orange ◽  
Transport Inhibitors ◽  
Auxin Transport Inhibitors ◽  
Indole 3 Acetic Acid

The effects of removal of young fruit and application of auxin transport inhibitors on endogenous indole-3-acetic acid (IAA) and abscisic acid (ABA) concentrations were examined in relation to the response of mature `Valencia' orange [Citrus sinensis (L.) Osb.] fruit to abscission materials. ABA concentrations were increased in the fruit abscission zone and pulp but not in the pedicel, peel, or seed of mature fruit by removal of young fruit during the period of reduced response of mature fruit to abscission materials in early May. However, removal of young fruit slightly decreased IAA concentrations in leaves and the abscission zone and pedicel of mature fruit but had no effect on the IAA concentrations in the peel, pulp, or seed of mature fruit. Young fruit had higher IAA concentrations in the abscission zone and pedicel than mature fruit. Application of 2,3,5-triiodobenzoic acid (TIBA), an IAA transport inhibitor, reduced IAA concentrations in the abscission zone of mature fruit but did not influence the IAA concentrations in the pedicel and peel when applied directly to an absorbent collar tied around the pedicel 2 cm above the fruit abscission zone during the less responsive period in early May. ABA concentrations were increased drastically in the fruit abscission zone and pedicel but not in peel by TIBA application. Applications of ABA, or IAA transport inhibitors such as naringenin, quercetin, or TIBA comparably increased the response of mature fruit to the abscission material 5-chloro-3-methyl-4-nitro-1 H-pyrazole (CMN-pyrazole) in early May. These data suggest that young fruit reduce the response of mature `Valencia' oranges to abscission materials through increasing IAA concentrations and decreasing ABA concentrations in the abscission zone of mature `Valencia' orangees.

scholarly journals Physiological Factors Affecting Response of Mature `Valencia' Orange Fruit to CMN-Pyrazole. II. Endogenous Concentrations of Indole-3-Acetic Acid, Abscisic Acid, and Ethylene

2001 ◽  
Vol 126 (4) ◽  
pp. 420-426 ◽  
Author(s):  
Rongcai Yuan ◽  
Ulrich Hartmond ◽  
Walter J. Kender
Keyword(s):  
Acetic Acid ◽  
Abscisic Acid ◽  
Ethylene Production ◽  
Abscission Zone ◽  
Endogenous Iaa ◽  
Fruit Abscission ◽  
Valencia Orange ◽  
Orange Fruit ◽  
Indole 3 Acetic Acid ◽  
Observation Period

Endogenous concentrations of IAA and ABA in the peel, pulp, seed, and abscission zone of mature `Valencia' oranges [Citrus sinesis (L.) Osbeck] were determined by high-performance liquid chromatography and enzyme-linked immunosorbent assay from early November 1998 to mid-June 1999. Ethylene production of mature `Valencia' oranges during the same period was determined by gas chromatography. IAA concentrations in the pulp and seed were three to five times lower than those in the peel over the 7-month observation period. IAA concentration in the abscission zone and peel was high from late April to mid-May, the period of less responsiveness to abscission chemicals. ABA concentration in the pulp was low over the entire observation period. ABA concentration in the abscission zone and peel was low during the less responsive period. Ethylene production was always low except for a slight increase during late December and early February. The IAA to ABA ratio was high in the fruit abscission zone during the less responsive period. Fruit detachment force of CMN-pyrazole-treated fruit was positively correlated with the ratio of endogenous IAA to ABA or endogenous IAA, but negatively to endogenous ABA in the fruit abscission zone. These data suggest the balance between IAA and ABA in the fruit abscission zone may be an important factor in determining sensitivity and thereby the response of mature `Valencia' orange fruit to abscission chemicals. Chemical names used: abscisic acid (ABA); indole-3-acetic acid (IAA); 5-chloro-3-methyl-4-nitro-1H-pyrazole (CMN-pyrazole).

scholarly journals Cellulase Activity and Gene Expression in Citrus Fruit Abscission Zones during and after Ethylene Treatment

1998 ◽  
Vol 123 (5) ◽  
pp. 781-786 ◽  
Author(s):  
William C. Kazokas ◽  
Jacqueline K. Burns
Keyword(s):  
Gene Expression ◽  
Cellulase Activity ◽  
Storage Period ◽  
Abscission Zone ◽  
Cellulase Gene ◽  
Immature Fruit ◽  
Ethylene Treatment ◽  
Fruit Abscission ◽  
Valencia Orange ◽  
Low Levels

Mature and immature `Valencia' orange [Citrus sinensis (L.) Osbeck] and immature `Valencia' orange and `Tahiti' lime (Citrus latifolia Tan.) fruit with attached pedicels were treated with 8 μL·L-1 ethylene for periods up to 24 hours. Endo-β-1,4-glucanase (cellulase) activity and gene expression were determined in fruit abscission zones during and after ethylene exposure. Cellulase activities were not detected in mature `Valencia' orange and immature `Tahiti' lime fruit abscission zones immediately following harvest and after 6 hours of ethylene treatment. After 12 hours of ethylene treatment, cellulase activity increased and was highest after 24 hours. Cellulase gene expression preceded the rise in cellulase activity and was detectable after 6 hours of ethylene treatment, but then declined after 12 hours. Following transfer to air storage, abscission zone cellulase activity in mature `Valencia' fruit remained high, whereas activity in immature `Tahiti' fruit declined. After 168 hours air storage, activity in abscission zones of mature `Valencia' fruit decreased slightly, but activity in abscission zones of immature `Tahiti' lime fruit increased to the highest level. Expression of abscission zone cellulase gene Cel-a1 in abscission zones of mature `Valencia' fruit markedly increased after transfer to air and was highest after 48 hours air storage. Cel-a1 expression returned to low levels after 168 hours of air storage, but expression of cellulase gene Cel-b1 remained at low levels throughout the air storage period. Expression of Cel-a1 and Cel-b1 declined in fruit abscission zones of immature `Valencia' and `Tahiti' lime fruit upon transfer to air. After 168 hours of air storage, expression of Cel-a1 again rose to high levels but Cel-b1 remained low. The results suggest that differences in cellulase activity and gene expression measured in mature and immature fruit abscission zones during ethylene treatment and subsequent air storage may, in part, explain the differential response of mature and immature fruit to abscission agents.

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