scholarly journals Reviewing the Commercial Potential of Hand Thinning in Citrus with a Cost-benefit Analysis of Summer Hand Thinning of ‘Nadorcott’ Mandarin

2016 ◽  
Vol 26 (2) ◽  
pp. 206-212 ◽  
Author(s):  
Ockert P.J. Stander ◽  
Paul J.R. Cronjé
Keyword(s):  
Growth Rate ◽  
Size Distribution ◽  
Fruit Quality ◽  
Cost Benefit Analysis ◽  
Fruit Size ◽  
Cultural Practice ◽  
Fruit Yield ◽  
Initial Growth ◽  
Alternate Bearing ◽  
Thinning Intensity

Hand thinning is not often applied as a commercial cultural practice in citriculture due to the practice’s reliance on costly manual labor. However, hand thinning could provide unique benefits such as treatment selectivity and easier control over thinning intensity, as opposed to foliar sprays of chemical thinning agents. In “on-year” ‘Nadorcott’ mandarin (Citrus reticulata) trees, summer (January) and autumn (April) hand-thinning treatments of removal of all fruit <20 and <40 mm diameter were evaluated for effects on leaf carbohydrates and fruit growth rate. Other factors assessed included treatments’ effects on tree total fruit yield, fruit quality, and fruit size distribution. In addition, two different summer hand-thinning treatments (removal of all fruit <20 and <25 mm) were evaluated for effects on fruit size distribution and fruit yield over two seasons to determine their potential financial implications. Summer hand thinning reduced the numbers of small fruit and increased initial growth rate of prevailing fruit. This resulted in larger numbers of premium-sized fruit per tree, without treatments reducing total fruit yield and fruit quality. Additional labor was eliminated by quicker picking of fruit during harvest, and in season 2, fruit yield was higher for summer hand-thinning treatments compared with control. A higher potential income resulted from change in fruit size distribution and the breaking of alternate bearing over the 2-year period. The results provide producers of late mandarin cultivars with an alternative to chemical thinning agents to manage crop load and improve fruit size in individual “on-year” trees.

The growth of apricot fruit. II. The effects of temperature and gibberellic acid

1967 ◽  
Vol 18 (1) ◽  
pp. 95 ◽  
Author(s):  
DI Jackson ◽  
BG Coombe
Keyword(s):  
Growth Rate ◽  
Cell Division ◽  
Gibberellic Acid ◽  
Fruit Size ◽  
Fruit Growth ◽  
Cell Diameter ◽  
Initial Growth ◽  
Endogenous Gibberellin ◽  
Flower Buds ◽  
Size And Shape

The effect of temperature and gibberellic acid (GA3) applications on apricot fruit have been determined by measurements of fruit size and shape, mesocarp cell number, size, and shape, and endogenous gibberellin. Application of heat during the first 10 nights after anthesis increased the initial growth rate of fruit and of cells in the mesocarp and produced more rapid cell division in this tissue. It did not affect final fruit size or the number and diameter of cells in the mesocarp. Higher temperatures did, however, hasten maturity of fruit. GA3 perfused into branches before anthesis produced an increased drop of flower buds and fruit, raised the ratio of flower buds to leaf buds initiated that season, and resulted in elongated pedicels. Initially, fruit growth rate was increased by GA3, but subsequently it was depressed and final size was below normal. These effects on fruit size were mainly due to effects on the rate of cell division. Some differences were noted in the dimensions of cells but final radial cell diameter did not differ from untreated fruit. GA3-treated fruit ripened sooner than controls. Neither heating nor GA3 treatments affected the level of endogenous gibberellin-like substances in the fruit or their RF on paper chromatograms. There were no significant interactions between temperature and gibberellin in any parameter of apricot fruit growth.

Improving fruit size and packout of Late Valencia oranges with ethephon fruit-thinning sprays

1992 ◽  
Vol 32 (6) ◽  
pp. 753 ◽  
Author(s):  
RJ Hutton
Keyword(s):  
Fruit Quality ◽  
Fruit Size ◽  
High Volume ◽  
Cropping Pattern ◽  
Alternate Bearing ◽  
Fruit Thinning ◽  
Unaffected Control ◽  
Marketable Fruit ◽  
Orange Trees ◽  
Spray Treatment

This study set out to establish concentrations of ethephon sprays that could reliably thin alternate cropping orange trees in a heavy set year to improve fruit quality for fresh marketing. An optimum concentration of ethephon as a thinning agent was identified for the practical control of alternate cropping in Late Valencia oranges. A single, high volume spray of ethephon (as Ethrel, 42-60 mL/100 L water), applied in a heavy-set year at 6-8 weeks post bloom when fruitlet size was 10-15 mm diameter, induced a 15-20% reduction in fruit number. This resulted in significantly improved fruit size and marketable outturn with negligible yield penalty. In the 2 successive harvests following spray treatment, the cropping pattern remained uniform and a 14% improvement in packout (marketable fruit size <100 counts per carton) was maintained. Internal fruit quality was unaffected. Control of alternate bearing was carried forward for at least 2 seasons with relatively stable yields following a single spray treatment.

scholarly journals Influences of girdling and potassium treatments on fruit quality and some physiological characters of ‘Fremont’ mandarin variety

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Tuğba Ülker ◽  
Müge Uysal Kamiloğlu
Keyword(s):  
Fruit Quality ◽  
Sugar Content ◽  
Chlorophyll Concentration ◽  
Fruit Size ◽  
Potassium Nitrate ◽  
Leaf Nitrogen ◽  
Fruit Yield ◽  
Leaf Nitrogen Content ◽  
Total Sugar Content ◽  
N Concentration

Abstract Growing citrus involves cultural treatments such as girdling and foliar potassium treatment to increase fruit size, yield and quality. The aim of the study was to evaluate the effects of single and double stem girdling, potassium nitrate (KNO3) treatment on leaves and combinations of these treatments on the fruit yield, size and quality characteristics, leaf chlorophyll concentration and leaf nitrogen content, leaf fluorescence (PSII) and leaf sugar content of the ‘Fremont’ mandarin variety. Girdling treatments were applied on the stem by removing 4 mm wide ring of bark at the end of anthesis and after the June fruit drop. Foliar KNO3 applications were applied at a concentration of 4% twice (90 days and 120 days after full anthesis) in the experiment. The single girdling (SG) and double girdling (DG) treatments on stems increased fruit yield (kg · tree−1) by approximately 40% relative to the control (C). Treatments did not significantly affect the internal fruit quality of the ‘Fremont’ mandarin variety except in fruit colour and appearance. The highest impact on fruit size was found in the DG + KNO3 treatment. According to treatments and periods, the SPAD values varied between 62.08 and 70.67, whereas the PSII values varied between 0.698 and 0.756. The treatments significantly increased the leaf nitrogen (N) concentration and the fructose, glucose and sucrose concentrations relative to the control. The highest N concentration content was detected in the foliar potassium treatment, and the highest total sugar content was detected in the SG treatment.

scholarly journals The Potential Use of Metamitron as a Chemical Fruit-thinning Agent in Mandarin

2018 ◽  
Vol 28 (1) ◽  
pp. 28-34 ◽  
Author(s):  
Ockert P.J. Stander ◽  
Johané Botes ◽  
Cornelius Krogscheepers
Keyword(s):  
Fruit Set ◽  
Fruit Size ◽  
Fruit Trees ◽  
Fruit Yield ◽  
Citrus Reticulata ◽  
Alternate Bearing ◽  
Fruit Thinning ◽  
Total Carbohydrates ◽  
Leaf Carbohydrates ◽  
Potential Use

Under conditions of profuse flowering and excessive fruit set, citrus (Citrus sp.) fruit need to be thinned to increase the size of remaining fruit, reduce the intensity of alternate bearing, or both. Metamitron was recently developed as a chemical fruit-thinning agent for apple (Malus ×domestica) and pear (Pyrus communis), and it inhibits photosynthesis and is thought to transiently reduce the carbohydrate pool in fruit trees. Citrus trees are sensitive to carbohydrate stress during and immediately after flowering, but the response of citrus to foliar treatment with a photosynthesis inhibitor, such as metamitron, is unknown. The purpose of this study was to evaluate metamitron for its effects on leaf carbohydrates and its ability to chemically thin citrus fruitlets. Significant fruit-thinning effects were found in all the experiments conducted over two seasons. A 300 mg·L−1 metamitron treatment reduced leaf sugars and leaf total carbohydrates, and consistently reduced the total number of fruit per tree in both seasons in ‘Nadorcott’ mandarin (Citrus reticulata), irrespective of the timing of application. In the second season, a reduction in fruit yield was reported with an increase in metamitron concentration, both in mass and number of fruit per tree. A 150 mg·L−1 metamitron treatment in November had no fruit-thinning effects, and fruit yield was not different from the control. The application of metamitron did not increase the fruit size of ‘Nadorcott’ mandarin and had no direct effect on other fruit quality attributes in either season. Metamitron can be used as a chemical fruit-thinning agent to reduce fruit numbers in ‘Nadorcott’ mandarin, but an increase in fruit size or quality should not be expected.

scholarly journals New Particle Formation and Sub-10 nm Size Distribution Measurements during the A-LIFE field experiment in Paphos, Cyprus

2019 ◽  
Author(s):  
Sophia Brilke ◽  
Nikolaus Fölker ◽  
Thomas Müller ◽  
Konrad Kandler ◽  
Xianda Gong ◽  
...  
Keyword(s):  
Growth Rate ◽  
Particle Size ◽  
Field Experiment ◽  
Size Distribution ◽  
Particle Formation ◽  
Atmospheric Environment ◽  
Aerosol Size Distribution ◽  
Initial Growth ◽  
New Particle Formation ◽  
Nucleation Mode

Abstract. Atmospheric particle size distributions were measured in Paphos, Cyprus, during the A-LIFE (Absorbing aerosol layers in a changing climate: aging, lifetime and dynamics) field experiment from April 3–30, 2017. The newly developed DMA-train is deployed for the first time in an atmospheric environment for the direct measurement of the nucleation mode size range between 1.8–10 nm diameter. The DMA-train setup consists of seven size channels, of which five are set to fixed particle mobility diameters and two additional diameters are obtained by alternating voltage settings in one DMA every 10 s. In combination with a conventional Mobility Particle Size Spectrometer (MPSS) and an Aerodynamic Particle Sizer (APS) the complete atmospheric aerosol size distribution from 1.8 nm–10 µm is covered. The focus of the A-LIFE study is to characterize new particle formation (NPF) in the Eastern Mediterranean region at a measurement site with strong local pollution sources. The nearby Paphos airport was found to be a large emission source for nucleation mode particles and we analysed the size distribution of the airport emission plumes at approximately 500 m from the main runway. The analysis yielded 9 NPF events in 27 measurement days from the combined analysis of the DMA-train, MPSS and trace gas monitors. Growth rate calculations were performed and a size-dependency of the initial growth rate (

scholarly journals Crop Load, Fruit Thinning and their Effects on Fruit Quality of Apple (Malus domestica Borkh.)

2006 ◽  
pp. 29-35 ◽  
Author(s):  
József Racskó
Keyword(s):  
Growth Rate ◽  
Fruit Quality ◽  
Fruit Size ◽  
Flower Initiation ◽  
Pome Fruit ◽  
Cross Sectional ◽  
Crop Load ◽  
Fruit Thinning ◽  
Return Bloom ◽  
Tree Leaf

Crop load, a quantitative parameter used by industry, is generally defined as the number of fruit per tree. It is often expressed in terms of number of fruit per trunk cross-sectional area (fruit/TCSA). Crop load is the most important of all factors that influence fruit size, and the removing of a part of the crop is the most effective way to improve fruit size.The potential size of a given pome fruit is determined early in the season and growth proceeds at a relatively uniform rate thereafter. This uniform growth rate permits the accurate prediction of the harvest size of the fruit as early as mid-summer. The growth rate, once established, is not easily altered, and fruit numbers, therefore, can affect fruit size only within definite limits and maximum effectiveness requires adjustment in fruit numbers relatively early in the season. It was established, that „thinning does not change a potentially small fruit into a large fruit, but rather insures that a potentially large fruit will size properly.” Emphasis should be on estimating fruit numbers rather than fruit size.Fruit thinning can quickly reach the point of diminishing returns. Rather than a high percentage of large fruits, the objectives of thinning should be the elimination of the smallest fruits, improved fruit quality and annual production. Fruit thinning is accomplished by hand or chemical thinning. Chemical thinners are separated into categories as bloom thinners and post-bloom thinners. Early removal of potential fruit (blossom thinning) is currently used in many apple producing areas to enhance flower initiation for next year’s crop and thus, return bloom. It also results in reduced competition for photosynthates. Blossom thinners usually have a caustic effect on floral parts.The amount of fruit left on a tree should be determined by the vigor and general condition of the tree. Leaf area per fruit affects the number of spurs flowering the following season. It can be difficult to separate timing and fruit number effects in crop loading studies, as abscission rates after hand thinning of retained flowers/fruitlets tend to very with the time of hand thinning.

scholarly journals The diversity of ‘kristal’ guava (Psidium guajava) fruit quality in response to different altitudes and cultural practices

2020 ◽  
Vol 21 (7) ◽  
Author(s):  
Neni Musyarofah ◽  
Slamet Susanto ◽  
Sandra Arifin Aziz ◽  
Ketty Sukety ◽  
Dadang DADANG
Keyword(s):  
Fruit Quality ◽  
Cultural Practices ◽  
Fruit Size ◽  
Psidium Guajava ◽  
Cultural Practice ◽  
Guava Fruit ◽  
Randomized Design ◽  
Low Altitude ◽  
Different Altitudes

Abstract. Musyarofah N, Susanto S, Aziz SA, Suketi K, Dadang. 2020. The diversity of ‘kristal’ guava (Psidium guajava) fruit quality in response to different altitudes and cultural practices. Biodiversitas 21: 3310-3316. The current study aimed to compare the quality of ‘kristal’ guava fruit harvested from different altitudes under different cultural practices. The study was conducted from January to March 2019. Four treatments were examined, i.e., fruit from low altitude-intensive cultural (LI), low altitude-less intensive cultural (LI), middle altitude-intensive cultural (MI), and middle altitude-less intensive cultural (ML). All treatments were arranged in a completed randomized design and each treatment had five trees as replicates The findings of the study showed that there was a variation of fruit quality in response to different altitudes and cultural practices. The fruits harvested from low altitudes were significantly bigger and heavier than the fruits harvested from middle altitude, irrespective of cultural practices. With regard to fruit softness, the fruits from middle altitudes were crispier than fruits from the low altitude. The chemical qualities of the fruits, indicated by TSS/TA ratio and vitamin C, were better in guava orchard under intensive cultural practice than less intensive cultural practice. The intensive cultural practice also improved the guava fruit size as compared to the less intensive cultural practice. This finding may be attributed to pruning which is performed in intensive cultural practice. More beneficial metabolites for human health such as vitamin E and caryophyllene were found in fruit from low altitude.

scholarly journals Yield, fruit quality, and survival of 'Pêra' sweet orange on eight rootstocks in tropical cohesive soils

2021 ◽  
Vol 56 ◽  
Author(s):  
Hélio Wilson Lemos de Carvalho ◽  
Luciana Marques de Carvalho ◽  
Adenir Vieira Teodoro ◽  
Inácio de Barros ◽  
Eduardo Augusto Girardi ◽  
...  
Keyword(s):  
Fruit Quality ◽  
Sweet Orange ◽  
Block Design ◽  
Cohesive Soil ◽  
Fruit Production ◽  
Fruit Yield ◽  
High Yield ◽  
Alternate Bearing ◽  
Yield Efficiency ◽  
Tree Survival

Abstract: The objective of this work was to determine the influence of eight rootstocks on the yield, fruit quality, and survival of 'Pêra CNPMF D6' sweet orange (Citrus sinensis) trees grown under rainfed conditions in a cohesive soil of the Brazilian Northeast. In 2014-2018, the yield, fruits, and survival of trees planted in 1997 were evaluated in a randomized complete block design. Yield was assessed using annual fruit production, yield efficiency, and the alternate bearing index. Tree survival was considered the percentage of plants that remained alive until 2018. Fruit quality was evaluated by physicochemical attributes. 'Cravo' confirmed its good yield performance. Despite the lower number of trees, the 'Mazoe' rough lemon rootstock induced the highest fruit yield. The 'Cravo' x 'Cleópatra' hybrid and 'Volkameriano' lemon favored the highest trees survival, whereas 'Indio' citrandarin and 'Cravo' lime resulted in intermediate levels. The 'San Diego' and 'Riverside' citrandarins induced shorter tree with a high yield efficiency and a higher alternate bearing index, respectively. Fruits with less juice and mass were induced, respectively, by 'Riverside' citrandarin and 'Volkameriano' lemon. It can be concluded that the 'Mazoe' rootstock induces a higher fruit yield and 'Cravo' x 'Cleópatra' and 'Volkameriano', a greater survival. In addition, all rootstocks, except 'Riverside' and 'Volkameriano', induce fruit that meet the minimum quality requirements.

scholarly journals Effect of Reflective Fabric on Yield of Mature ‘d’Anjou’ Pear Trees

HortScience ◽  
2012 ◽  
Vol 47 (11) ◽  
pp. 1580-1585 ◽  
Author(s):  
Todd C. Einhorn ◽  
Janet Turner ◽  
Debra Laraway
Keyword(s):  
Growth Rate ◽  
Fruit Quality ◽  
Cold Storage ◽  
Sugar Content ◽  
Fruit Size ◽  
Fruit Growth ◽  
Full Bloom ◽  
Final Size ◽  
Response Curves ◽  
Fruit Number

Reflective fabric was installed before bloom in 2009 and 2010 in alleyways of a mature, low-density ‘Anjou’ pear orchard (269 trees/ha). Four treatments were applied to study intracanopy light environments on fruit growth rate and size, cropload, yield, and fruit quality: 1) no fabric (NF); 2) partial-season fabric applied before full bloom (FB) and removed 75 days after full bloom (dafb) (PSF); 3) full-season fabric applied before FB and removed at harvest (FSF); and 4) shadecloth (60%) applied 60 dafb through harvest (SC). PSF and FSF improved yield by 12% and 18%, respectively, over the two-year period relative to NF. The high yields of fabric treatments were attributed to fruit number in the lower (less than 2.4 m) interior, mid-, and exterior zones of the canopy. Photosynthetic active radiation (PAR) was increased by fabric 28%, 95%, and 30% in the lower exterior, mid-, and interior canopy, respectively. Photosynthesis:light response curves indicated improved carbon assimilation of pear leaves developing in the elevated PAR environment of the lower canopy. Fruit growth rate and final size were unaffected by fabric treatments. FSF fruit size was similar to NF despite higher fruit density. Compared with NF, FSF had a small, non-significant effect on fruit maturity (increased softening) at harvest. Yield and fruit size of SC fruit were significantly reduced. The number of fruit in SC trees did not differ from NF in 2009, but the effect of shade reduced fruit number in 2010. Fabric did not affect fruit quality attributes after three and six months of regular atmosphere cold storage. Pears from SC trees did not attain ripening capacity after three months of cold storage and a 7-day ripening period and had lower sugar content compared with other treatments. The cumulative yield advantages associated with FSF support its use in mature pear orchards.

Sign in / Sign up

Export Citation Format

Share Document