scholarly journals Foliar 2,4-D Application after Physiological Fruit Drop Reduces Fruit Splitting of Mandarin

2014 ◽  
Vol 24 (6) ◽  
pp. 717-723 ◽  
Author(s):  
Ockert P.J. Stander ◽  
Karen I. Theron ◽  
Paul J.R. Cronjé

Various mandarin (Citrus reticulata) cultivars are prone to fruit splitting, a physiological disorder that entails cracking of the rind, starting from the stylar end of the fruit, with eventual splitting of the endocarp and abscission of the fruit. On two mandarin cultivars, Marisol and Mor, foliar applications of 2,4-dichlorophenoxyacetic acid (2,4-D), calcium (Ca), and potassium (K) were evaluated over two growing seasons for efficacy to reduce fruit splitting in Paarl, South Africa (lat. 33°69′S, long. 18°95′E). Foliar treatment of 10 mg·L−1 2,4-D directly after physiological fruit drop (APFD) compared with later dates in January and February, either alone or in combination with K, increased rind thickness and reduced fruit splitting of ‘Marisol’ and ‘Mor’ by up to 50%, without negatively affecting internal fruit quality. Treatments increased rind thickness and rind strength throughout fruit development in addition to fruit diameter, length, and growth rate, with no significant effect on rind coarseness. There was a slight reduction in juice content and titratable acidity (TA), but no effect on the total soluble solids (TSS). Application of 2,4-D APFD is thought to increase rind integrity due to a direct strengthening effect on the rind during early stages of fruit development.

2019 ◽  
Vol 41 (5) ◽  
Author(s):  
Ricardo Antonio Ayub ◽  
Iohann Metzger Bauchrowitz ◽  
Clandio Medeiros da Silva ◽  
Isabela Leticia Pessenti ◽  
Fernanda Grimaldi ◽  
...  

Abstract In order to test the use of ammonia thiosulfate (ATS) in the chemical thinning of the Japanese plum tree, a field experiment was conducted throughout the 2015/2016 and 2016/2017 crop growing seasons at Ponta Grossa, PR, Brazil. The experimental design adopted herein was a randomized block design (RBD). During the 2015/2016 season, the trial was comprised of two accesses and six treatments, such as T1 (control); T2 (ATS 4%); T3 (ATS 5%); T4 (ATS 6%); T5 (ATS 7%) and T6 (manual thinning) with four replications. During the 2016/2017 season, solely one plum tree access was taken into account along with six treatments, such as T1 (control); T2 (ATS 6%); T3 (ATS 7%); T4 (ATS 8%); T5 (ATS 9%) and T6 (manual thinning) and four replications. The evaluations were performed seven days before the application of ATS and 30 days before harvest to establish the percentage of fruit drop. The following response variables were assessed: diameter (D), fresh mass (MF), firmness (N), soluble solids (SS), titratable acidity (AT), ratio, pH and plant production (PP). Experimental data were compared by means of the Tukey test at 5% probability. The concentration of 8 % ATS was efficient in the chemical thinning of the Japanese plum fruits, having a diameter and productivity similar to the manual thinning, evidencing that such a product was amenable to enhance commercial fruit quality.


2021 ◽  
Vol 43 (5) ◽  
Author(s):  
João Claudio Vilvert ◽  
Sérgio Tonetto de Freitas ◽  
Maria Aparecida Rodrigues Ferreira ◽  
Eleonora Barbosa Santiago da Costa ◽  
Edna Maria Mendes Aroucha

Abstract The objective of this study was to determine the most efficient sample size required to estimate the mean of postharvest quality traits of ‘Palmer’ mangoes harvested in two growing seasons. A total of 50 mangoes were harvested at maturity stage 2, in winter (June 2020) and spring (October 2020), and evaluated for weight, length, ventral and transverse diameter, skin and pulp L*, C* and hº, dry matter, firmness, soluble solids (SS), titratable acidity (TA) and the SS/TA ratio. According to the results, the coefficient of variation (CV) of fruit quality traits ranged from 2.1% to 18.1%. The highest CV in both harvests was observed for the SS/TA ratio, while the lowest was reported for pulp hº. In order to estimate the mean of physicochemical traits of ‘Palmer’ mangoes, 12 fruits are needed in the winter and 14 in the spring, considering an estimation error of 10% and a confidence interval of 95%. TA and the SS/TA ratio required the highest sample size, while L* and hº required the lowest sample size. In conclusion, the variability was different among physicochemical traits and seasons, implying that different sample sizes are required to estimate the mean of different quality traits in different growing seasons.


HortScience ◽  
2019 ◽  
Vol 54 (9) ◽  
pp. 1532-1539 ◽  
Author(s):  
Corina Serban ◽  
Lee Kalcsits ◽  
Jennifer DeEll ◽  
James P. Mattheis

‘Honeycrisp’ apples are susceptible to bitter pit, a physiological disorder that impacts peel and adjacent cortex tissue. ‘Honeycrisp’ is also susceptible to chilling injury (CI) that can be prevented by holding fruit at 10 to 20 °C after harvest for up to 7 days. This temperature conditioning period reduces CI risk but can enhance bitter pit development. Previous research demonstrated a controlled atmosphere (CA) established during conditioning can reduce ‘Honeycrisp’ bitter pit development without inducing other physiological disorders. The objective of this research was to evaluate the duration of CA needed to reduce bitter pit development. Experiments were conducted in 2014, 2016, and 2017 with fruit obtained from commercial orchards in Washington State and, in 2017 only, Ontario, Canada. Half the fruit were treated with 42 µmol·L−1 1-methycyclopropene (1-MCP) for 24 hours at 10 °C immediately following harvest. The untreated fruit were held at the same temperature (10 °C) in a different cold room. Following 1-MCP treatment, all fruit were conditioned at 10 °C for an additional 6 days, then fruit was cooled to 2.8 °C. During conditioning, fruit were held in air or CA (2.5 kPa O2, 0.5 kPa CO2) established 1 day after harvest, for 1 to 8 weeks, then in air. All fruit were removed from cold storage after 4 months and then held 7 days at 20 °C. Fruit from most orchards/years stored in CA developed less bitter pit compared with fruit stored continuously in air. CA during conditioning also reduced poststorage peel greasiness but CA for 2 weeks or longer enhanced cortex cavity development in some orchard lots. Treatment with 1-MCP did not reduce bitter pit but enhanced development of peel leather blotch and core browning for some orchards/years. 1-MCP–treated fruit slowed the loss of soluble solids content, titratable acidity, and reduced internal ethylene concentration. Results suggest the potential for postharvest management of bitter pit development in ‘Honeycrisp’ apples by CA established during conditioning with minimal development of other postharvest disorders.


HortScience ◽  
2009 ◽  
Vol 44 (3) ◽  
pp. 666-670 ◽  
Author(s):  
Todd W. Wert ◽  
Jeffrey G. Williamson ◽  
Jose X. Chaparro ◽  
E. Paul Miller ◽  
Robert E. Rouse

The effect of climate was observed on fruit quality of four low-chill peach cultivars (Flordaprince, Flordaglo, UFGold, and TropicBeauty). The cultivars were evaluated in three locations (north–central, central, and southwest Florida). Soluble solids content (SSC), titratable acidity (TA), SSC:TA ratio, fruit weight, blush, and fruit development period (FDP) were determined. Longer FDPs were observed at the north–central location than at the southwest location. Fruit development and the expression of quality attributes were affected by location during fruit growth with higher color and SSC and shorter FDP occurring under warmer conditions. Within locations, ‘UFGold’ had the shortest FDP except at the southwest location where its chilling requirement may not have been met. At the central and southwest locations, ‘UFGold’ also tended to have lower TA values and higher SSC;TA ratios than the other cultivars.


2008 ◽  
Vol 30 (4) ◽  
pp. 892-896 ◽  
Author(s):  
Paulo Roberto Ernani ◽  
Jaques Dias ◽  
Cassandro Vidal Talamini do Amarante ◽  
Diorvânia Cardoso Ribeiro ◽  
Douglas Antonio Rogeri

Calcium sprays have normally improved both the quality and the storage life of apples throughout the world because Ca helps to prevent many fruit disorders and that taken up from the soil does not often reach the fruit in adequate amounts. Since the efficacy of Ca sprays varies according to soil, apple cultivar, and weather conditions, this study was carried out from 1998 to 2004, in the Southern of Brazil, in order to assess the effect of Ca sprays on the quality and storability of 'Gala' fruits. The experiment was set up in an orchard planted in 1988, on a density of 1234 trees/ha. Treatments consisted of 0, 4, 8, and 12 annual sprays of 0.5% CaCl2 regularly distributed 30 days after petal fall until one week before harvest. Fruits of the same size and maturity level were annually analyzed at harvest and after five months of conventional cold storage (-1ºC and 90-95% of RH). In five out of six seasons, fruits from all treatments were free of any physiological disorder, and Ca sprays had no effect on leaf composition and on any fruit attribute (soluble solids, titratable acidity, starch pattern index, flesh firmness, and concentrations of N, K, Ca and Mg). In the season of 2000/2001, however, when yield was 18 t ha-1 and fruits had an average weight of 175 g, the incidence of bitter pit plus lenticel blotch pit on stored fruits was 24% in the treatment with no calcium sprays and it decreased up to 2% in that with 12 sprays. Two seasons later, yield was also low (25 t ha-1) and fruits were large (168 g each), but they did not show any physiological disorder regardless of the number of Ca sprays. It seems that the incidence of Ca related disorders in 'Gala' apples grown on limed soils in Brazil with no excess of any nutrient only occurs on seasons with low crop yield, as a result of large fruits and a high leaf/fruit ratio, associated with some unknown environmental conditions.


2015 ◽  
Vol 140 (5) ◽  
pp. 490-503 ◽  
Author(s):  
Elizabeth A. Baldwin ◽  
John W. Scott ◽  
Jinhe Bai

Thirty-eight tomato (Solanum lycopersicum L.) genotypes were analyzed for sensory attributes “sweet,” “sour,” and “overall flavor” over 7 years, one to three seasons per year (March, June, and December) as well as for physical and chemical flavor-related attributes including color, sugars, acids, and aroma volatiles (6–7 years). Principal component analysis of the data of nine genotypes showed that for harvest season, December-harvested fruit were generally associated with more acids and sourness perception and less sugars and sweetness perception and, therefore, lower overall flavor ratings compared with June-harvested fruit. March-harvested samples were intermediate. Despite the seasonal variations, there were significant differences between genotypes for sensory perception of sweetness, sourness, and flavor, between seasons for sourness and flavor, and between years for flavor, with some interactions between genotypes, seasons, and years. In addition to sugar and acid measurements, 29 aroma volatiles were evaluated in 33 genotypes over the seasons. Eleven volatiles were found to positively correlate with flavor perception and 13 enhanced flavor along with the soluble solids/titratable acidity ratio in a two-predictor model, providing aroma targets for breeders. Among the genotypes evaluated most frequently were the Florida industry standard ‘Florida 47’ and University of Florida hybrid ‘Fla. 8153’ which was released in 2006 and is now marketed as Tasti-Lee®. ‘Florida 47’ was almost always rated lower for sweet and overall flavor compared with ‘Fla. 8153’. On a 1–9 hedonic scale, where 1 was least sweet, sour, or flavorful and 9 was most sweet, sour, or flavorful, average scores over the 7 years were 3.8 and 5.1 for sweet and 4.1 and 5.7 for overall flavor for ‘Florida 47’ and ‘Fla. 8153’, respectively. Other genotypes related to ‘Fla. 8153’, including its parents, were also rated high for sweet and overall flavor compared with ‘Florida 47’ and other commercial cultivars grown in Florida. Correspondingly, sugar measurements were higher, while acid measurements were slightly lower for ‘Fla. 8153’ compared with ‘Florida 47’. Thirteen out of 29 aroma compounds showed differences between these two genotypes, with eight being higher in ‘Fla. 8153’ (including many fruity/floral notes) and four higher in Florida 47 (C-5 and C-6 aldehydes and alcohols giving green notes). This provides a useful chemical model for two genotypes that differ in flavor quality that can be exploited by breeders seeking to improve flavor.


Agronomy ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 730 ◽  
Author(s):  
Neocleous ◽  
Nikolaou

This study was commissioned to study the effect of the growing season on the antioxidant components of greenhouse sweet pepper crops, which is of scientific interest because of their possible beneficial health effects. The total antioxidant activity (estimated by ferric reducing antioxidant power-FRAP assay) major antioxidants (ascorbic acid, phenolics and carotenoids) and taste fruit quality characteristics (soluble solids, titratable acidity, dry matter and sugars) were recorded in soilless-grown sweet pepper cultivars of red, orange, yellow and green color at four harvesting season months, i.e., February (winter), May (spring), July (summer) and October (autumn). The results showed seasonal variations in antioxidant components and activity of pepper fruits. In most cases measured parameters showed higher values in spring (May) and summer (July) compared with winter (February) and autumn (October) growing seasons. This study indicates that during late autumn and winter, lower levels of solar irradiance, ultraviolet radiation and temperature in Mediterranean greenhouses can be insufficient to stimulate phytochemicals production in peppers; thus, plant–light interception must be more actively managed.


2008 ◽  
Vol 43 (3) ◽  
pp. 333-340 ◽  
Author(s):  
Cassandro Vidal Talamini do Amarante ◽  
Cristiano André Steffens ◽  
Álvaro Luiz Mafra ◽  
Jackson Adriano Albuquerque

The objective of this study was to assess the yield and fruit quality of apple produced with a conventional and an organic production systems in Southern Brazil. The orchards consisted of alternate rows from 10 to 12-year old 'Royal Gala' and 'Fuji' apple trees on M.7 rootstocks, grown as slender spindles, on 4x6 m spacing. Eighteen apple trees of each cultivar and management system were randomly selected and assessed for nutrition, flowering, fruit set, yield, and fruit quality during two growing seasons (2002/2003 and 2003/2004). The organic management system resulted in lower concentrations of K, Mg, and N in leaves and fruits, and in smaller fruits for both cultivars, and lower fruit yield for 'Fuji' than from the conventional production system. For both cultivars, fruits from the organic orchard harvested at commercial maturity had a more yellowish skin background color, higher percentage of blush in the fruit skin, higher soluble solids content, higher density, higher flesh firmness, and higher severity of russet than fruits from the conventional orchard. Fruit from the organic orchard had lower titratable acidity in 'Royal Gala', and higher incidence of moldy core and lower incidence of watercore in 'Fuji', than fruit from the conventional orchard. A non-trained sensory panel detected no significant differences for fruit attributes of taste, flavor and texture between fruit from the production systems for either cultivar.


2019 ◽  
Vol 20 (5) ◽  
pp. 1126 ◽  
Author(s):  
Chaoyang Hu ◽  
Huiyu Zhao ◽  
Jianxin Shi ◽  
Jian Li ◽  
Xiangbo Nie ◽  
...  

The auxin-like compound 2,4-dichlorophenoxyacetic acid (2,4-D) has been widely used as a plant growth regulator in cucumber fruit production; however, its influence on fruit development and metabolism has not been evaluated. In this study, the phenotype of cucumber fruits in both 2,4-D treatment and non-treatment control groups were recorded, and the metabolome of different segments of cucumber fruit at various sampling time points were profiled by a standardized non-targeted metabolomics method based on UPLC-qTOF-MS. The application of 2,4-D increased the early growth rate of the fruit length but had no significant effect on the final fruit length, and produced cucumber fruits with fresh flowers at the top. The 2,4-D treatment also affected the cucumber fruit metabolome, causing significant changes in the stylar end at 4 days after flowering (DAF). The significantly changed metabolites were mainly involved in methionine metabolism, the citric acid cycle and flavonoid metabolism pathways. At the harvest stage, 2,4–D treatment significantly decreased the levels of flavonoids and cinnamic acid derivatives while increased the levels of some of the amino acids. In summary, exogenous application of 2,4-D can greatly alter the phenotype and metabolism of cucumber fruit. These findings will assist in exploring the mechanisms of how 2,4-D treatment changes the fruit phenotype and evaluating the influence of 2,4-D treatment on the nutritional qualities of cucumber fruit.


2011 ◽  
Vol 11 (2) ◽  
pp. 141-148 ◽  
Author(s):  
José Airton Rodrigues Nunes ◽  
Francisco Ferreira Santana ◽  
Regina Lúcia Ferreira Gomes ◽  
Ângela Celis de Almeida Lopes ◽  
Maria Marlúcia Gomes Pereira ◽  
...  

This study aimed to estimate genetic parameters and identify promising clones of Spondias mombin in ungrafted commercial crop by stratified mass selection, based on the average of two harvests, using mixed models. The base population growing on a private farm in Teresina/PI comprised 82 plants, which were evaluated in the growing seasons 2008 and 2009. Total titratable acidity (TTA), total soluble solids (Brix), Brix/TTA, fruit weight (FW), seed weight (SW), pulp yield (PuY), and processing yield (PrY) were measured. Significant genetic variation among plants was detected for all traits. The coefficients of repeatability were 0.97 (TTA), 0.39 (Brix), 0.86 (Brix/TTA), 0.84 (FW), 0.82 (SW), 0.35 (PuY), and 0.39 (PrY). The chemical were generally not correlated with the physical fruit traits. Ranking by predicted phenotypic values associated with PrY and Brix/TTA identified nine promising plants (PrY>6.9% and Brix/TTA>10).


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