scholarly journals Ethephon as a Blossom and Fruitlet Thinner Affects Crop Load, Fruit Weight, Fruit Quality, and Return Bloom of ‘Summerred’ Apple (Malus ×domestica) Borkh.

HortScience ◽  
2011 ◽  
Vol 46 (3) ◽  
pp. 432-438 ◽  
Author(s):  
Mekjell Meland ◽  
Clive Kaiser

‘Summerred’ apples (Malus domestica Borkh.) are highly susceptible to biennial bearing if not properly thinned. This results in erratic yields and also affects fruit quality adversely. Between 2003 and 2005, ‘Summered’/‘M9’ trees were treated with ethephon at concentrations of 250, 375, and 500 mg·L−1 when most king flowers opened (≈20% bloom) or at concentrations of 500, 625, and 750 mg·L−1 when the average fruitlet size was 10 mm in diameter. The experiment was conducted with 2.5-m height slender spindle trees sprayed to the point of runoff with a hand applicator only when temperatures exceeded 15 °C. Within 2 weeks after the second application, fruit set was reduced linearly with increasing concentrations of ethephon to less than one fruitlet per cluster at the highest concentrations used. Most thinning treatments reduced fruit set significantly compared with unthinned trees. Fruit numbers per tree decreased significantly with increasing ethephon concentrations, and the highest concentrations of ethephon applied during bloom or when the average fruitlet size was 10 mm in diameter resulted in overthinning. Yield results confirmed the fruit set response in which yield reductions were significant at the highest concentrations of ethephon (2.1 kg/tree) compared with hand-thinned trees (7.3 kg/tree) in 2005. All thinning treatments resulted in higher percentage of fruits larger than 60 mm diameter compared with unthinned control fruit. Thinning resulted in significantly higher soluble solid contents, and this was especially so for hand-thinned trees. Other fruit quality parameters like yellow–green background color did not show a clear response to thinning. Return bloom was, however, improved on all thinned trees. It is recommended that ethephon be applied at a rate of 375 mg·L−1 when king flowers open or at a rate of 625 mg·L−1 when the average fruitlet size is 10 mm in diameter. This thins ‘Summerred’ apples to a target of approximately five fruits/cm2 per trunk cross-sectional area or 50 to 70 fruits per 100 flower clusters without impacting on fruit quality, yield, or return bloom the next year.

HortScience ◽  
2007 ◽  
Vol 42 (7) ◽  
pp. 1622-1625 ◽  
Author(s):  
Charles G. Embree ◽  
Marina T.D. Myra ◽  
Douglas S. Nichols ◽  
A. Harrison Wright

From 2003 to 2006, the blossom level and crop load of ‘Honeycrisp’ apple (Malus × domestica Borkh.) trees on M.26 rootstocks were adjusted to improve fruit quality and return bloom. The treatments consisted of manually removing flower clusters to 50, 100, and 150 per tree, then at ≈50 d after full bloom, the crop load was adjusted to 3, 6, and 9 fruit/cm2 trunk cross-sectional area (TCSA), respectively. All flower and crop load adjustment significantly increased TCSA and canopy volume compared with the control. Classic biennial bearing was observed on the untreated control trees and those thinned to 150 blossom clusters per tree and 9 fruit/cm2 TCSA and was mitigated for trees with 50 and 100 blossom clusters followed by crop load adjustment to 3 and 6 fruit/cm2 TCSA, respectively. Fruit color the “on” year was always lower on the control trees; no difference was found in the “off” year. The treatments increased fruit weight proportional to crop load except for the 2004 “off” year. This study illustrates that for trees with ≈1 m3 canopy volume, the combined effects of blossom and crop load adjustment to 100 blossom clusters/tree followed by fruitlet adjustment to 6 fruit/cm2 TCSA and below will induce consistent annual production for ‘Honeycrisp’.


2017 ◽  
Vol 39 (4) ◽  
Author(s):  
MATEUS DA SILVEIRA PASA ◽  
BRUNO CARRA ◽  
CARINA PEREIRA DA SILVA ◽  
MARLISE NARA CIOTTA ◽  
ALBERTO FONTANELLA BRIGHENTI ◽  
...  

ABSTRACT The low fruit set is one of the main factors leading to poor yield of pear orchards in Brazil. Ethylene is associated with abscission of flowers and fruitlets. Then, the application of ethylene synthesis inhibitors, such as AVG, is a potential tool to increase fruit set of pears. The objective of this study was to evaluate the effect of AVG, sprayed at different rates and timings, on fruit set, yield and fruit quality of ‘Rocha’ pear. The study was performed in a commercial orchard located in the municipality of São Joaquim, SC, during the growing seasons of 2014/2015 and 2015/2016. Plant material consisted of ‘Rocha’ pear trees grafted on quince rootstock ‘BA29’. AVG was tested at different rates (60 mg L-1 and 80 mg L-1) and timings [full bloom, one week after full bloom (WAFB), and two WAFB), either alone or in combination. The experiment was arranged in a randomized block design, with at least five single-tree replications. The fruit set, number of fruit per tree, yield, estimated yield, fruit weight, return bloom, and fruit quality attributes were assessed. Fruit set and yield were consistently increased by single applications of AVG at 60 and 80 mg L-1 at both one and two weeks after full bloom, without negatively affecting fruit quality attributes and return bloom.


HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 798A-798
Author(s):  
Alireza Talaie* ◽  
Ali Gharaghani ◽  
Mohammad Ali Asgari

In this research the effect of four clonal rootstocks (B9, M9, M26, and MM106) on growth characteristics, flowering and fruiting, and fruit quality and quantity of `Golden Smoothee' apple (Malus × domestica Borkh.) were studied during 2001 and 2003. Trees were 8 years old at the beginning of study. Experiments were planned in randomized complete-block design with four treatments (four rootstocks) and four replications. Rootstocks had significant effects on all growth characteristics. The highest tree height, shoot growth, and tree cross-sectional area were found on MM106; with B9 was the least and M9 and M26 were intermediate. The effect of year, and interaction of year on rootstocks were nonsignificant. Rootstock has highly affected flowering and fruiting characteristics. The highest flowering efficiency related to M9 and B9. The highest primary and secondary fruit set and fruit set efficiency found with M9 and M26. The highest preharvest fruit abscission observed with M26. The M9 had the least preharvest fruit abscission. Yield of M9 was the highest and B9 was the least. The M9 has the most yield efficiency and MM106 had the least. Effect of year was significant in many characteristics related to flowering and fruiting. Generally, trees had better conditions in first year. Among fruit quantitative treatments, rootstock only affected fruit weight significantly. Fruit harvested from B9 had the least weight and other rootstocks had similar fruit weight. Generally rootstock had no noticeable effect on fruit quantity and quality.


2005 ◽  
Vol 85 (2) ◽  
pp. 453-455
Author(s):  
C. G. Embree ◽  
D. S. Nichols

Honeycrisp™ [Malus × domestica (L.) Borkh.] can be a very profitable cultivar if fruit quality is high. Some crop-load bio-regulators were evaluated for improving fruit quality and annual flowering. Ammonium thiosulphate applied at full bloom reduced crop-load, increased fruit weight, fruit colour and return bloom. Fruitone N® combined with Sevin XLR® reduced the percent of fruit in the 40–60% colour category and also crop-load. Fruitone N® alone reduced crop-load. Key words: Honeycrisp™, fruit thinning, crop-load, return bloom


HortScience ◽  
2005 ◽  
Vol 40 (3) ◽  
pp. 587-591 ◽  
Author(s):  
Vittorio Farina ◽  
Riccardo Lo Bianco ◽  
Paolo Inglese

Canopy shape and depth may influence crop uniformity of peach trees at harvest. To test this hypothesis we examined yield distribution and fruit quality changes at different canopy levels of peach trees trained to delayed vase (DV) and perpendicular Y (Y). Trees of both training forms were divided vertically into six or seven 50-cm-deep layers and fruit was harvested at commercial ripening from each layer separately. Regardless of training form, number of fruit and yield per layer were highest in the central part of the canopy, but more evenly distributed among canopy layers in Y trees. In DV trees, fruit weight decreased linearly from top to bottom, whereas it remained constant along the top and middle portion of Y canopies to decrease rapidly at the bottom. In DV trees, 83% of the fruit fell into AAA, AA and A size categories, whereas fruit of Y trees was more evenly distributed among all size categories. Hue of fruit peel color increased linearly with distance from canopy top in both training forms, but more sharply in DV trees. Fruit soluble solid content decreased linearly from canopy top to bottom, regardless of training form. A more uniform crop load distribution within the canopy in combination with a light penetration gradient resulted in greater variability of quality parameters for Y than DV trees.


HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 482D-482 ◽  
Author(s):  
David E. Davis ◽  
John A. Barden ◽  
Ross E. Byers

In 1997 and 1998, we determined the effects of defoliation on return bloom and fruit set following a light cropping year. In one study, `Braeburn' trees were hand-thinned to a crop density (CD) of 3 fruit/cm 2 trunk cross sectional area (TCSA) in late May 1997, and then either completely defoliated or half of the tree defoliated by hand on one of five dates between June and Sept. 1997. Compared to a nondefoliated control, both whole and half-tree defoliation on all dates reduced fruit count and yield efficiency (kilograms per square centimeter of TCSA) and affected fruit weight, starch, firmness, and soluble solids in 1997. In 1998, return bloom and fruit set were reduced by most 1997 defoliation treatments. Compared to other dates, defoliation on 3 July caused the greatest reduction in return bloom in both whole and half-defoliated trees. In another study, `Braeburn' trees were hand-thinned to a CD of 5 in late May 1998; complete defoliation by hand on 1, 15, or 29 July reduced return bloom and fruit set in 1999; the 1 July treatment resulted in zero return bloom. `Golden Delicious' and `York' trees were thinned to a CD of 3 in late May 1998 and were hand-defoliated on 21 July or 12 August by removing every other leaf or removing three of every four leaves over the entire tree. In 1999, return bloom and spur and lateral fruit set were reduced by all defoliation treatments. Fruit set was most reduced by the 12 Aug. treatment. Fruit set for `York' was lower than for `Golden Delicious' in all cases.


HortScience ◽  
2013 ◽  
Vol 48 (1) ◽  
pp. 40-46 ◽  
Author(s):  
Thomas M. Kon ◽  
James R. Schupp ◽  
H. Edwin Winzeler ◽  
Richard P. Marini

The objectives of this experiment were to test the efficacy of a mechanical string thinner (Darwin PT-250; Fruit-Tec, Deggenhauserertal, Germany) on apple and to identify an optimal range of thinning severity as influenced by spindle rotation speed. Trials were conducted in 2010 and 2011 at the Pennsylvania State University Fruit Research and Extension Center in Biglerville, PA, on five-year-old ‘Buckeye Gala’/M.9 apple trees that were trained to tall spindle. A preliminary trail on five-year-old ‘Cripps Pink’/M.9 was conducted to determine the relationship between string number and thinning severity. As the number of strings increased, the level of thinning severity increased. A range of spindle speeds (0 to 300 rpm) was applied to the same trees for two consecutive years. As spindle speed increased, blossom density (blossom clusters per limb cross-sectional area) was reduced as was the number of blossoms per spur. In 2010, leaf area per spur was reduced 9% to 45%. In 2011, the fastest spindle speed reduced leaf area per spur 20%. Although increased spindle speed reduced cropload, injury to spur leaves may have inhibited increases in fruit size. The largest gain in fruit weight was 28 g (300 rpm) compared with the control. In both years, the most severe thinning treatments reduced yield by more than 50%. There was no relationship between spindle speed and return bloom. Severe thinning treatments (240 to 300 rpm) caused significant reductions in spur leaf area, yield, and fruit calcium and did not improve fruit size or return bloom. Spindle speeds of 180 and 210 rpm provided the best overall thinning response and minimized injury to spur leaves, but cropload reduction was insufficient in years of heavy fruit set. Therefore, mechanical blossom thinning treatments should be supplemented with other thinning methods. Mechanical string thinning may be a viable treatment in organic apple production, where use of chemical thinners is limited.


1994 ◽  
Vol 119 (3) ◽  
pp. 389-395 ◽  
Author(s):  
Esmaeil Fallahi ◽  
Brenda R. Simons ◽  
John K. Fellman ◽  
Mark A. Longstroth ◽  
W. Michael Colt ◽  
...  

Twenty-six strains of `Delicious' apple (Malus domestica Borkh.) were evaluated over several years for growth, yield, and fruit quality at harvest and after 6 months of storage. `August Red', `Rose Red', and `Sharp Red' had larger trunk cross-sectional area (TCSA) 3 and 18 years after planting compared to most other strains. `August Red' and `Starking' had larger TCSA and cumulative yield. `Apex,' `Improved Ryan Spur', `Silverspur', `Starkrimson', and `Wellspur' were also among strains with high cumulative yields and yield efficiencies. `Hardi-Brite Spur' and `Red King Oregon Spur' had moderately high yields and small TCSAs, thus, high yield efficiencies. `Atwood', `Hardispur', `Imperial', `Improved Ryanred', `Starkspur Supreme', and `Topred' had low cumulative yields. `Ace' and `Improved Ryanred' had low yield efficiencies. `Ace', `Imperial', `Red King Oregon Spur', `Rose Red', `Starking', and `Wellspur' had heavier fruit, while fruit weight in `August Red', `Hardispur', and `Starkrimson' was lighter than that in most other strains. `Redspur' and `Starkspur Supreme' had the largest length to diameter (L/D) ratios. `Early Red One' had a similar red skin color rating as `Rose Red.' The red skin color rating of `Early Red One' was significantly higher than that of all other strains. `Hi-Early', `Improved Ryanred', `Redspur', and `Starking' had the poorest skin color ratings. `Hardispur', `Nured Royal', `Silverspur', and `Starkrimson' had high soluble solids concentrations (SSCs) at harvest and after storage. `Early Red One', `Imperial', `Improved Ryan Spur', and `Red King Oregon Spur' had lower SSCs at harvest and after storage. Fruit of `Apex' and `Redspur' had relatively high firmness at harvest, while `Hardispur', `Silverspur', `Starkrimson', and `Starkspur Supreme' had firm fruit at harvest and after storage. `Hardi-Brite Spur' had the softest fruit after storage, and fruit from `Rose Red' had a lower firmness than most other strains at harvest and after storage. Considering cumulative yield, yield efficiency, or some quality parameters, `Apex', `Classic Red', `Improved Ryan Spur', `Red King Oregon Spur', `Silverspur', and `Wellspur' had satisfactory overall performance. Strains are also suggested for planting depending on the market situation and the demand for a particular quality factor. `Hardispur' and `Sturdeespur' (Miller) are not recommended for planting under climatic conditions similar to those of this experiment.


2005 ◽  
pp. 39-43
Author(s):  
József Racskó ◽  
Miklós Soltész ◽  
Lejla Budai ◽  
Zoltán Szabó ◽  
Ervin Farkas ◽  
...  

The authors studied the effect of rootstocks with different growing vigour on fruit quality of different cultivars. Research results shows that best fruit diamter and fruit weight of all cultivars are for M9 rootstock. Similar tendency was found in skin colour, but in the case of Granny Smith, MM106 rootstock is more favourable because the green skin colour is necessary for the consumers’ acceptance. Seedling rootstok has some unfavourable effects on fruit quality, thus its usage is not expedient.


2018 ◽  
Vol 45 (No. 3) ◽  
pp. 111-118
Author(s):  
Walid Mosa ◽  
Lidia Sas Paszt ◽  
Mateusz Frąc ◽  
Paweł Trzciński ◽  
Michał Przybył ◽  
...  

hese experiments began with the planting of maiden apple trees of cv. ‘Topaz’ in 2011. In springtime in 2012–2016, chemical fertilisation (NPK) and various natural bioproducts, namely Fertigo, Micosat, Humus UP, Humus Active + Aktywit PM, Aktywit PM, BioFeed Quality, BioFeed Amin, Vinassa, Florovit Natura and Florovit Eko were applied to the apple trees alone or enriched with Pantoea sp., Pseudomonas fluorescens, Klebsiella oxytoca and Rhizobium bacterial species. Growth, yield and fruit quality parameters were then evaluated. Our results reveal that the trunk cross-sectional area was greatly increased by the addition of the beneficial bacteria to Humus UP, Yeast, Vinassa and Micosat, as compared to NPK chemical fertilisation. Yeast, Vinassa, Micosat, Humus UP and BioFeed Amin enriched with the beneficial bacteria significantly increased fruit weight in kg and the number of fruits compared to the NPK control in 2015 and 2016.  


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