scholarly journals Abscission of Orange Fruit (Citrus sinensis (L.) Osb.) in the Mediterranean Basin Depends More on Environmental Conditions Than on Fruit Ripeness

Agronomy ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 591 ◽  
Author(s):  
Hajer Khefifi ◽  
Rim Selmane ◽  
Mehdi Ben Mimoun ◽  
Francisco Tadeo ◽  
Raphael Morillon ◽  
...  
Keyword(s):  
Citrus Fruit ◽  
Soluble Solids ◽  
Fruit Maturation ◽  
Fruit Abscission ◽  
Fruit Drop ◽  
Fruit Maturity ◽  
Citrus Production ◽  
Orange Fruit ◽  
The Mean ◽  
Maturity Parameters

Orange fruit abscission usually occurs at the final stage of fruit maturation but in some areas of citrus production, in advance of the usual harvest period, and sometimes suddenly and intensely. The reasons for this precocious citrus fruit abscission remains unclear. Therefore, the aim of this study was to try to clarify what the determinants of this phenomenon are. A multi-site experimentation was carried out on six orange cultivars, in Corsica, Spain and Tunisia where the phenomenon of early massive fruit drop varies. Climatic parameters, fruit maturity parameters and fruit detachment force (FDF) were recorded along the fruit maturation period. Respectively to the fruit drop, the FDF decreased in Tunisia and in Spain until the fruit falls, whereas in Corsica, it remained relatively constant throughout fruit maturation. Although data on fruit maturity parameters (rind color, acidity and total soluble solids) differed at the three sites, their evolution was similar during the period of maturation. FDF was not related to changes in any fruit maturity parameters, and more likely depended on changes in temperatures on days when the mean temperature was above 13 °C. Massive fruit abscission could be linked to the earlier more rapid restart of vegetative growth in Tunisia and Spain than in Corsica.

scholarly journals Fruit Abscission and Fruit Quality of Apples Following Use of Dicamba to Control Preharvest Drop

1990 ◽  
Vol 115 (3) ◽  
pp. 390-394 ◽  
Author(s):  
Richard P. Marini ◽  
Ross E. Byers ◽  
Donald L. Sowers ◽  
Rodney W. Young
Keyword(s):  
Fruit Quality ◽  
Starch Content ◽  
Soluble Solids ◽  
Naphthaleneacetic Acid ◽  
Soluble Solids Content ◽  
Fruit Abscission ◽  
Fruit Drop ◽  
Solids Content ◽  
Methoxybenzoic Acid

Five apple (Malus domestica Borkh.) cultivars were treated with dicamba at concentrations of 0 to 200 mg·liter-1 during 3 years. Although the response varied with cultivar, dose, and year, dicamba always delayed fruit abscission. At similar concentrations, dicamba usually reduced fruit drop more than NAA, but less than fenoprop. Dicamba at 10 mg·liter-1 effectively delayed drop of `Delicious', whereas 20 to 30 mg·liter-1 was required for `Red Yorking', `Rome', `Winesap', and `Stayman'. Dicamba did not influence flesh firmness, soluble solids content, water core, or starch content at harvest or after storage. Chemical names used: naphthaleneacetic acid (NAA); 2-(2,4,5-trichlorophenoxy)propionic acid (fenoprop); 3,6dichloro-2-methoxybenzoic acid (dicamba).

scholarly journals Characteristics of Citrus Canker Lesions Associated with Premature Drop of Sweet Orange Fruit

2019 ◽  
Vol 109 (1) ◽  
pp. 44-51 ◽  
Author(s):  
Fabrício E. Lanza ◽  
Weber Marti ◽  
Geraldo J. Silva ◽  
Franklin Behlau
Keyword(s):  
Sweet Orange ◽  
Linear Regression Analysis ◽  
Negative Relationship ◽  
Citrus Fruit ◽  
Citrus Canker ◽  
Multiple Linear Regression Analysis ◽  
Detachment Force ◽  
Fruit Drop ◽  
Orange Fruit ◽  
The Relationship

During the development of a citrus fruit, many cycles of infection by Xanthomonas citri subsp. citri may occur leading to the development of a range of characteristics of citrus canker lesions scattered across the fruit surface. This study aimed to determine whether the size of the lesions, their distance from the peduncle, and the number and time of appearance of the lesions on fruit of sweet orange were associated with premature fruit drop. A multiple linear regression analysis revealed a negative relationship between the fruit detachment force and the lesion diameter, the proximity of the nearest lesion to the peduncle and the number of lesions. A survival analysis demonstrated that these characteristics significantly influenced the probability and the time that a cankered fruit remained attached to the tree. More than 90% of dropped fruit had large lesions (>5 mm) but not all fruit with large lesions dropped before harvest. Approximately 50% of the harvested fruit had lesions >5 mm. On the harvested fruit remaining on the tree, although large, the lesions had a smaller diameter, were located farther from the peduncle, and were less numerous than those observed on dropped fruit. Small canker lesions neither reduced the detachment force nor the survival of fruit in the tree. The earlier a fruit expressed canker symptoms, the higher the probability the fruit developed large lesions near the peduncle and/or developed lesions in greater numbers. This study provides a better understanding on the relationship between the time of appearance of lesions of citrus canker on fruit and premature fruit drop. This information defines the critical period for fruit protection and may be used to improve disease management.

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 116 Preharvest Fruit Drop Studies, Harvest Quality, and Cold Storage of `Golden Delicious' and `Rome' Apples

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 409A-409
Author(s):  
R.E. Byers ◽  
D.H. Carbaugh ◽  
L.D. Combs
Keyword(s):  
Cold Storage ◽  
Soluble Solids ◽  
Application Time ◽  
Fruit Drop ◽  
Fruit Maturity ◽  
Golden Delicious ◽  
Full Rate ◽  
Equivalent Control ◽  
Reduced Rate ◽  
Fruit Diameter

Combinations of aminoethoxyvinylglycine (AVG, ReTain) and NAA gave better control of fruit drop of `Golden Delicious' than either alone. When the full rate of ReTain (50 g/A) was compared to a reduced rate of ReTain (86 g/ha) plus NAA, equivalent control of fruit drop of `Golden Delicious' resulted. ReTain delayed softening and starch depletion of `Golden Delicious' fruit. NAA in some cases promoted earlier fruit maturity; but when used in combination with ReTain, maturity was similar to ReTain-treated fruit. Fruit with the highest firmness and starch came out of cold storage in the best condition. Neither 1-methylcyclopropene (MCP, EthylBloc) or NAA inhibited fruit drop of `Golden Delicious' fruit when applied at harvest; but previous ReTain and NAA data indicate that late applications are frequently much less effective than if applied 4 weeks before harvest. Ethephon spray treatments caused more rapid and extensive fruit drop than the control. Trees gassed or sprayed with EthylBloc before ethephon sprays also dropped rapidly. `Golden Delicious' fruit on the tree were dramatically maintained firmer by the EthylBloc gas, and to a lesser extent by EthylBloc sprays by 19.1 N and 10.2 N firmness, respectively, tested on 28 Oct. Starch was maintained by the EthylBloc gas, but not by the sprays. These data indicated that EthylBloc applied as a gas or spray did have a physiological affect but did not control fruit drop. Fruit diameter, soluble solids and color did not appear to be affected. Further study of earlier applications of EthylBloc or combinations with fruit drop control agents may be needed to get fruit drop control. NAA plus Silwet L-77 inhibited fruit drop of `Law Rome', but none of the EthylBloc sprays inhibited fruit drop when applied at harvest. Previous data with ReTain and NAA indicated that late applications are frequently much less effective than if applied 4 weeks before harvest. EthylBloc sprays applied 21 Oct. dramatically maintained fruit firmness tested on 3 Nov. Starch was not maintained by the EthylBloc gas, but starch had almost disappeared by the application time on 21 Oct. Fruit diameter, soluble solids, and color did not appear to be affected. Further study of earlier applications of EthylBloc may be needed to demonstrate fruit drop control. Shading trees with 92% polypropylene shade material for 3 or 7 days caused more rapid fruit abscission at 7 days than 3 days and both were greater than the control.

scholarly journals (128) Effect of 2,4-DP Concentration on Fruit Drop Control and Maturation of `Braeburn' Apples

HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 1062B-1062
Author(s):  
Patricia Garriz ◽  
Graciela Colavita ◽  
Hugo Alvarez ◽  
Valeria Blackhall
Keyword(s):  
Apple Fruit ◽  
Soluble Solids ◽  
Management Tool ◽  
Control Treatment ◽  
Starch Degradation ◽  
Potential Yield ◽  
Uniform Size ◽  
Fruit Abscission ◽  
Synthetic Auxin ◽  
Fruit Drop

Apple fruit abscission shortly before harvest is a frequent, recurring problem, thereby reducing potential yield. The synthetic auxin 2 (2,4-dichlorophenoxy) propionic acid (2,4-DP) was evaluated for its effect on reducing fruit drop and influencing ripening of `Braeburn' apples, in the High Valley region of Río Negro, Argentina (38°56'S, 67°59'W). Thirteen-year-old apple trees grafted on MM 111 rootstock were sprayed on 4 Mar. 2005, at 162 days after full bloom (DAFB) with 2,4-DP at doses of 0.05% and 0.10% (v/v), applied with an airblast sprayer, until runoff. Each tree was trained to palmette and planted in a single row from north to south with spacing of 2.3–4.0 m. The following measurements were performed: a) accumulated fruit drop, twice per week and b) maturity indices, weekly. Samples of uniform-size fruits were assessed for maturity (n = 20 per date and treatment), from 167 (commercial harvest) to 195 DAFB. On 23 Mar. (at 181 DAFB), cumulative fruit drop for control treatment was 19.9%, whereas 2,4-DP significantly reduced it to 4.90% and 2.94% at 0.05% and 0.10% (v/v), respectively. Reduction in the drop was also significant later, and 2,4-DP at both doses controlled drop comparably. The synthetic auxin did not affect fruit quality and maturation, based upon flesh firmness, starch degradation, and soluble solids concentration. We conclude that 2,4-DP is an effective drop control compound and it is useful as a management tool to increase yield by reducing fruit abscission and to extend the harvesting window of `Braeburn' apples, since it does not affect ripening. Delaying harvest may provide flexibility for scheduling of labor, fruit processing and packaging, cold storage, and marketing.

scholarly journals Rootstocks Influence Yield Precocity, Productivity, and Pre-Harvest Fruit Drop of Mandared Pigmented Mandarin

Agronomy ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1305
Author(s):  
Marco Caruso ◽  
Alberto Continella ◽  
Giulia Modica ◽  
Claudia Pannitteri ◽  
Riccardo Russo ◽  
...  
Keyword(s):  
Fruit Quality ◽  
Agricultural Research ◽  
Fruit Size ◽  
Citrus Fruit ◽  
High Sensitivity ◽  
Quality Parameters ◽  
Poncirus Trifoliata ◽  
Soluble Solids ◽  
Citrus Paradisi ◽  
Fruit Drop

Citrus fruit quality and scion productivity are influenced by the choice of rootstock. We aimed to evaluate the effect of rootstocks on yield and fruit quality of Mandared, a triploid pigmented mandarin. To do so, we established a rootstock field trial on a high pH soil (8.6) in which Mandared was grafted onto 11 rootstocks. These included some standard rootstocks, such as trifoliate orange ((Poncirus trifoliata (L.) Raf.), Troyer citrange (Citrus sinensis (L.) Osb. × P. trifoliata), Swingle citrumelo (Citrus paradisi Macf. × P. trifoliata), and C35 citrange (C. sinensis × P. trifoliata), as well as new releases from the Council for Agricultural Research and Economics (CREA, Acireale, Italy) and the University of California Riverside (UCR). The cumulative yield was measured over five consecutive years, while fruit quality was analyzed for two years. The trees on C35, C57 (Citrus sunki Hort. ex. Tan. × P. trifoliata), and C22 (C. sunki × P. trifoliata), started to set fruits one year earlier than the others. The trees on C57 provided some of the highest cumulative yields and canopy volumes. The production of Mandared grafted onto C57 was double that of Mandared grafted onto Troyer, while Mandared grafted onto C35 and C22 resulted in the best yield efficiency. The trees on Swingle and C57 significantly reduced the pre-harvest fruit drop, to which Mandared is particularly sensitive. However, grafting Mandared onto Swingle resulted in the highest variation among replicates, probably due to its high sensitivity to iron chlorosis. Most of the fruit quality parameters, such as fruit size, total soluble solids (TSS), and acidity were not significantly different among the rootstock treatments. However, fruits produced by Mandared grafted onto C22 had one of the highest rates of anthocyanin accumulation. The results indicate that C57, C35, and C22 were the most suitable rootstocks for Mandared in South-Eastern Sicily.

scholarly journals Citrus Fruit Abscission Induced by Methyl-jasmonate

2000 ◽  
Vol 125 (5) ◽  
pp. 547-552 ◽  
Author(s):  
Ulrich Hartmond ◽  
Rongcai Yuan ◽  
Jacqueline K. Burns ◽  
Angela Grant ◽  
Walter J. Kender
Keyword(s):  
Methyl Jasmonate ◽  
Citrus Sinensis ◽  
Field Experiments ◽  
Citrus Fruit ◽  
Leaf Abscission ◽  
Ethylene Concentration ◽  
Fruit Abscission ◽  
Detachment Force ◽  
Fruit Drop

Methyl jasmonate (MJ) was tested as a potential abscission chemical to enhance mechanical harvest of `Hamlin' and `Valenica' orange [Citrus sinensis (L.) Osb.]. In field experiments, a solution of 1, 5, 10, 20, or 100 mm MJ was applied either as a stem wrap to individual fruit or as a spray to entire trees or canopy sectors. Solutions of 10, 20, and 100 mm MJ resulted in significant and consistent reduction of fruit detachment force and caused fruit drop within 7 to 10 days. Fruit loosening was preceded by an increase in the internal ethylene concentration of fruit similar to that of other experimental abscission compounds. While concentrations of 10 mm and less caused no or negligible phytotoxicity, solutions exceeding 10 mm MJ induced unacceptable levels of leaf abscission.

scholarly journals Anatomical Observations of the Citrus Fruit Abscission Zone and Morphological Changes of the Cells during Secondary Physiological Fruit Drop

2017 ◽  
Vol 86 (4) ◽  
pp. 447-455 ◽  
Author(s):  
Xi Li ◽  
Akira Kitajima ◽  
Keiko Kataoka ◽  
Rihito Takisawa ◽  
Tetsuya Nakazaki
Keyword(s):  
Morphological Changes ◽  
Citrus Fruit ◽  
Abscission Zone ◽  
Fruit Abscission ◽  
Fruit Drop

scholarly journals Effect of aminoethoxyvinilglycine (AVG) on preharvest fruit drop and maturity of apples

2002 ◽  
Vol 24 (3) ◽  
pp. 661-664 ◽  
Author(s):  
Cassandro Vidal Talamini do Amarante ◽  
Anderson Simioni ◽  
Clarice Aparecida Megguer ◽  
Luiz Eduardo Bassay Blum
Keyword(s):  
Titratable Acidity ◽  
Fruit Growth ◽  
Soluble Solids ◽  
Control Treatment ◽  
Fruit Maturation ◽  
Flesh Firmness ◽  
Fruit Drop ◽  
Commercial Harvest ◽  
Red Color ◽  
Solids Content

Apple trees cultivars Gala and Fuji were sprayed four weeks before commercial harvest with aminoethoxyvinilglycine (AVG), at doses of 0, 125, or 250 mg L-1, and assessed for preharvest fruit drop, fruit growth, and maturation on tree. In 'Gala', 64 days after AVG spraying, fruit drop for control treatment was 85%, and AVG (at 125 and 250 mg L-1) reduced it to 10%. In 'Fuji', 64 days after AVG spraying, fruit drop for control was 6%, while treatments with AVG (at 125 and 250 mg L-1) increased fruit drop to 10%. AVG was a powerful retardant of fruit maturation for 'Gala' but not for 'Fuji'. In 'Gala', the most affected attribute was the skin background color, followed, in decreasing order, by soluble solids content, the starch index, skin red color, the flesh firmness, and titratable acidity. In 'Gala', only flesh firmness retention was improved by increasing AVG dose from 125 mg L-1 to 250 mg L-1. The AVG at 250 mg L-1 inhibited "Gala" late fruit growth but not 'Fuji'.

scholarly journals The Role of Colletotrichum spp. in Postharvest Anthracnose of Citrus and Survival of C. acutatum on Fruit

Plant Disease ◽  
1998 ◽  
Vol 82 (4) ◽  
pp. 415-418 ◽  
Author(s):  
L. W. Timmer ◽  
G. E. Brown ◽  
S. E. Zitko
Keyword(s):  
High Surface ◽  
Citrus Fruit ◽  
Fruit Drop ◽  
Citrus Groves ◽  
Valencia Orange ◽  
Orange Fruit ◽  
Colletotrichum Spp ◽  
Low Levels ◽  
Disease Free

Colletotrichum gloeosporioides causes postharvest anthracnose of citrus fruit and is a common saprobe in citrus groves, whereas C. acutatum infects flower petals and causes postbloom fruit drop (PFD). The purpose of this study was to determine whether C. acutatum caused anthracnose, survived as quiescent infections on fruit, and represented a threat for introduction of the PFD pathogen to disease-free areas. When Robinson tangerine fruit were artificially inoculated with both species and exposed to high levels of ethylene, only fruit inoculated with C. gloeosporioides developed postharvest anthracnose. However, C. acutatum was readily reisolated from inoculation sites on asymptomatic fruit. Navel oranges harvested from groves with severe PFD the previous spring developed low levels of anthracnose, but only C. gloeosporioi-des was isolated from lesions. Valencia orange fruit harvested at bloom during a PFD outbreak had high surface populations of C. acutatum which declined rapidly during 2 to 3 weeks of storage. Quiescent infections formed on artificially inoculated and naturally exposed fruit were reduced but not eliminated by washing, waxing, and fungicide treatment in the packinghouse. Since C. acutatum does not produce postharvest anthracnose, the risk of introduction of this pathogen to disease-free areas is minimal. However, if fruit were harvested during a PFD outbreak, C. acutatum might survive standard packinghouse treatment and shipment as quiescent infections.

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