scholarly journals Peach Blossom String Thinner Performance Improved with Selective Pruning

HortScience ◽  
2011 ◽  
Vol 46 (11) ◽  
pp. 1486-1492 ◽  
Author(s):  
James R. Schupp ◽  
T. Auxt Baugher
Keyword(s):  
Prunus Persica ◽  
Fruit Set ◽  
New Technology ◽  
Fruit Size ◽  
Tree Canopy ◽  
Production Costs ◽  
Training Systems ◽  
Canopy Access ◽  
Flower Density

Hand-thinning of fruit is among the most labor-intensive orchard practices and consequently contributes significantly to peach (Prunus persica) production costs. Prior research conducted by the authors on string blossom thinners for managing peach tree cropload demonstrated that this new technology reduces labor requirement and also improves fruit size. Studies were conducted over two seasons in peach orchards trained to perpendicular V or open-center systems to evaluate possible pruning strategies to improve tree canopy access by string thinners. The objectives were to demonstrate if modifications in fruiting shoot orientation, pruning detail, and/or scaffold accessibility improved flower removal, reduced follow-up hand-thinning requirement, and/or increased fruit size. Blossom removal was improved by either detailed pruning or partial pruning (elimination of all shoots on the side of a limb inaccessible by the thinner spindle) in both training systems. Flower density and fruit set measurements revealed greater differences among pruning treatments compared with hand-thinned control treatments with both fruiting shoot orientation pruning modifications and detail pruning resulting in improved thinning. Thinning efficacy was unaffected by scaffold angle but increased as canopy accessibility ranking increased. Follow-up hand-thinning time was reduced by all treatment, system/cultivar, and year combinations except standard pruning in an open center-trained 2009 trial. Detail pruning consistently improved fruit size compared with hand-thinned control and other pruning treatments in both perpendicular V- and open center-trained orchard plots. The best treatments resulted in a thinning savings of $120/ha to $282/ha in perpendicular V plantings and $26/ha to $46/ha in open-center plantings. Realized economic savings beyond hand-thinning alone ranged from $473/ha to $2875/ha in perpendicular V trials and $28/ha to $293/ha in open-center trials.

scholarly journals Mechanical String Thinner Reduces Crop Load at Variable Stages of Bloom Development of Peach and Nectarine Trees

HortScience ◽  
2010 ◽  
Vol 45 (9) ◽  
pp. 1327-1331 ◽  
Author(s):  
T. Auxt Baugher ◽  
K. Ellis ◽  
J. Remcheck ◽  
K. Lesser ◽  
J. Schupp ◽  
...  
Keyword(s):  
Prunus Persica ◽  
Positive Impact ◽  
New Technology ◽  
Fruit Size ◽  
Size Category ◽  
Crop Load ◽  
Spindle Rotation ◽  
Flower Density ◽  
Current Article

Thinning of blossoms or fruitlets is a labor-intensive requirement in the production of peach and nectarine (Prunus persica) fruit of optimum size and quality. Prior research conducted by the authors on string blossom thinners for managing peach tree crop load demonstrated that this new technology reduces labor requirement and improves fruit size. The research reported in the current article was conducted over 2 years on ‘Sugar Giant’ peach and ‘Arctic Sweet’ nectarine to evaluate string blossom thinner efficacy at variable stages of bloom development ranging from pink to petal fall. Blossom removal at the pink stage of bloom development was lower than at other stages in 2008; however, a 150-rpm versus 120-rpm spindle rotation speed resulted in blossom removal similar to the 80% full bloom (FB) treatment in 2009. Blossom removal at the petal fall stage was similar to the open bloom stage with the exception of the 2009 ‘Sugar Giant’ trial, in which blossom removal was higher at 80% FB. Flower density and fruit set of the bloom stage compared with hand-thinned control treatments followed a similar trend with the exception that there were fewer differences in 2009 and in lower canopy regions. Follow-up hand thinning time was reduced by all string thinning/year combinations except ‘Arctic Sweet’ at pink in 2008 and 2009 and at petal fall in 2009. The best treatments reduced follow-up hand thinning time compared with green fruit hand thinning alone by 51% and 41% for ‘Sugar Giant’ and by 42% and 22% for ‘Arctic Sweet’ in Years 1 and 2, respectively. In 2008, the percentage of fruit in the “7.0 cm or greater” size category was increased by all bloom stage treatments in both cultivars. The 2009 size distribution of ‘Arctic Sweet’ fruit was unaffected, but the percentage of ‘Sugar Giant’ fruit in higher market value size categories was increased by the 80% FB and higher rpm pink treatments. Savings in hand thinning time and/or increases in fruit size in both years associated with the bloom stage treatments resulted in a net positive impact of $123/ha to 1368/ha compared with hand thinning alone.

scholarly journals Horizontal String Blossom Thinner Reduces Labor Input and Increases Fruit Size in Peach Trees Trained to Open-center Systems

2009 ◽  
Vol 19 (4) ◽  
pp. 755-761 ◽  
Author(s):  
T. Auxt Baugher ◽  
J.R. Schupp ◽  
K.M. Lesser ◽  
K. Hess-Reichard
Keyword(s):  
Prunus Persica ◽  
Total Yield ◽  
Fruit Size ◽  
Production Costs ◽  
Labor Input ◽  
Combination Treatments ◽  
Tree Canopies ◽  
Mechanical Thinning ◽  
Peach Trees

Hand thinning of fruit is among the most labor-intensive orchard practices and consequently contributes significantly to peach (Prunus persica) production costs. Research reported in 2008 on a string blossom thinner for vertical tree canopies demonstrated that this new mechanical method has potential to favorably impact grower profitability by reducing labor requirement and by improving fruit size and quality. A string thinner prototype for open-center tree canopies was tested in six orchards in 2008. Peach blossom removal in upper canopy regions ranged from 23% to 69% with the new string thinner oriented in a horizontal or inclined position to thin the tops of vase-shaped trees. Optimal thinning with the horizontal string thinner was with a 2.0 km·h−1 tractor speed, reducing peach crop load by an average of 47%, reducing follow-up hand thinning time 32%, and increasing fruit in higher market size categories 22% to 31%. Net economic impact (realized economic savings) of mechanical thinning at 2.0 km·h−1 versus hand thinning alone ranged from $799 to $911 per hectare. Total yield was sometimes reduced by string thinner treatments; however, high-market-value yields were comparable across treatments. Two combination treatments—mechanical thinning followed by hand blossom thinning and thinning with a horizontal followed by a vertical string thinner—suggested additional strategies for achieving the most desirable thinning results.

scholarly journals Chemical Thinning of `Gala' Apples in California

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 525E-525
Author(s):  
Warren C. Micke ◽  
Joseph A. Grant ◽  
James T. Yeager
Keyword(s):  
Untreated Control ◽  
Fruit Set ◽  
Fruit Size ◽  
Apple Cultivar ◽  
The Third ◽  
Commercial Use

`Gala', the third most widely planted apple cultivar in California, requires early and precise thinning to produce good fruit size. Thus, chemical thinning would be ideally suited for this cultivar. However, the normally prolonged bloom for apples in California makes timing of chemical thinning applications difficult. In 1995 and 1996 trials, several chemical thinning treatments provided significantly reduced fruit set on `Gala' compared to the untreated control. Three treatments showed promise for commercial use: 1) carbaryl, two applications at petal fall and again at 10-15 mm diameter of the king fruit; 2) carbaryl plus NAD at petal fall; and 3) carbaryl plus 6-benzyladenine and GA4+7 (Accel®), two applications at petal fall and at ≈10 mm diameter of the king fruit. These treatments generally gave reduced fruit set per 100 flower clusters, fruit set per fruiting cluster and/or numbers of fruit removed by follow-up hand-thinning. None of these treatments showed evidence of phytotoxicity, and some increased fruit size over the untreated control.

scholarly journals Heritability, Genetic and Phenotypic Correlations, and Predicted Selection Response of Quantitative Traits in Peach: I. An Analysis of Several Reproductive Traits

1998 ◽  
Vol 123 (4) ◽  
pp. 598-603 ◽  
Author(s):  
Valdomiro A.B. de Souza ◽  
David H. Byrne ◽  
Jeremy F. Taylor
Keyword(s):  
Fixed Effects ◽  
Prunus Persica ◽  
Fruit Set ◽  
Genetic Correlations ◽  
Selection Response ◽  
Direct Selection ◽  
Multiple Trait ◽  
Narrow Sense Heritability ◽  
Phenotypic Correlations ◽  
Flower Density

Seedlings of 108 families from crosses among 42 peach [Prunus persica (L.) Batsch] cultivars and selections were evaluated for six plant characteristics in 1993, 1994, and 1995. The data were analyzed by using a mixed linear model, with years treated as fixed and additive genotypes as random factors. Best linear unbiased prediction (BLUP) was used to estimate fixed effects. Restricted maximum likelihood (REML) was used to estimate variance components, and a multiple trait model was used to estimate genetic and phenotypic covariances among traits. The narrow-sense heritability estimates were 0.41, 0.29, 0.48, 0.47, 0.43, and 0.23 for flower density, flowers per node, node density, fruit density, fruit set, and blind node propensity, respectively. Most genetic correlations among pairs of traits were ≥0.30 and were, in general, much higher than the corresponding phenotypic correlations. Flower density and flowers per node (ra = 0.95), fruit density and fruit set (ra = 0.84) and flower density and fruit density (ra = 0.71) were the combinations of traits that had the highest genetic correlation estimates. Direct selection practiced solely for flower density (either direction) is expected to have a greater effect on fruit density than direct selection for fruit density.

scholarly journals 660 Reducing Floral Initiation and Return Bloom in Stone Fruit Trees: Applications and Implications in Fruit Production

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 561F-562
Author(s):  
Stephen M. Southwick
Keyword(s):  
Prunus Persica ◽  
Fruit Set ◽  
Fruit Size ◽  
Fruit Production ◽  
Prunus Armeniaca ◽  
Climatic Conditions ◽  
Stone Fruit ◽  
Labor Costs ◽  
Flower Number ◽  
Prunus Salicina

Commercially grown apricots (Prunus armeniaca), peaches (Prunus persica), nectarines (Prunus persica), plums (Prunus salicina and Prunus domestica), and pluots (Prunus salicina × Prunus armeniaca) have a tendency to produce high numbers of flowers. These flowers often set and produce more fruit than trees can adequately size to meet market standards. When excessive fruit set occurs, removal of fruit by hand-thinning is common to ensure that fruit size meets market standards. Over the years there have been numerous attempts to find chemical or physical techniques that would help to reduce costs associated with and improve efficiencies of hand-thinning; however, using alternate strategies to hand-thinning have not been widely adopted in stone fruit production. In the past 10 years, through the continuing efforts of scientists throughout the world in public and private institutions and business, it appears that there are chemical sprays capable of reducing the need for hand-thinning in stone fruit. Management of flowering by reducing the number of flowers on apricot, peach, nectarine, plum, and prune has shown promise under climatic conditions such as those found in the San Joaquin Valley of California. By applying gibberellins during May through July, flowers in many stone fruit cultivars can be reduced in the following season. The reduction in flower number does not generally lead to an increase in fruit set. As a result, fruit numbers are reduced, the need for hand thinning can be reduced, and in some cases eliminated. There are risks associated with reducing flower number before climatic conditions during bloom or final fruit set are known. However, given the changes in labor costs and market demands, especially in the developed world, the benefits may outweigh the risks. The application and implications of these summer gibberellin applications toward reducing flower numbers will be discussed as it relates to commercial stone fruit growing.

scholarly journals Bloom Thinning of `Loadel' Cling Peach with a Surfactant: Effects of Concentration, Carrier Volume, and Differential Applications within the Canopy

1998 ◽  
Vol 8 (1) ◽  
pp. 55-58 ◽  
Author(s):  
Stephen M. Southwick ◽  
Kitren G. Weis ◽  
James T. Yeager ◽  
Michael E. Rupert ◽  
Janine K. Hasey
Keyword(s):  
Prunus Persica ◽  
Fruit Set ◽  
Fruit Size ◽  
Weather Conditions ◽  
Flower Bud ◽  
Tree Fruit ◽  
Before And After ◽  
Return Bloom ◽  
Carrier Volume ◽  
Surfactant Effects

In 1994, we established that a surfactant, Armothin (AR), reduced fruit set when applied as 3% and 5% AR at 100 gal/acre with a Stihl mistblower to `Loadel' clingstone peach [Prunus persica (L.) Batsch]. In 1995 we compared 3% AR at volumes of 100 and 200 gal/acre (935 and 1870 L.ha-1, the volumes most commonly used by tree fruit growers in California) applied with commercial airblast sprayer; overthinning resulted with the latter. In 1996, we applied 3% AR at 100 gal/acre and 1% AR at 200 gal/acre. In 1995, differential applications of 3% AR at 100 gal/acre (two-thirds of the material applied to either the upper or lower canopy) reduced fruit set in the upper canopy in proportion to the amount of chemical applied (twice as much fruit set reduction with twice as much chemical); fruit set in the lower canopy was reduced by an equal amount regardless of amount of chemical used. Salable yields, equivalent to those obtained by hand thinning, and improved fruit size were achieved with all treatments of 3% AR at 100 gal/acre in 1995 with a 76% reduction in hand thinning. Following a low-chill winter (1995-96) with a protracted bloom, flower bud density (return bloom) was significantly greater in 1995 AR-treated trees. In 1996, treatment with AR did not result in fruit set reduction due to the protracted bloom and poor weather conditions before and after bloom. Nonetheless, 1% AR at 200 gal/acre applied in 1996 increased salable yield and increased final fruit mass. Return bloom in 1997 was equal among 1996 treatments.

scholarly journals Tergitol-TMN-6 Surfactant Is an Effective Blossom Thinner for Stone Fruits

HortScience ◽  
2006 ◽  
Vol 41 (5) ◽  
pp. 1243-1248 ◽  
Author(s):  
Esmaeil Fallahi ◽  
Bahar Fallahi ◽  
James R. McFerson ◽  
Ross E. Byers ◽  
Robert C. Ebel ◽  
...  
Keyword(s):  
Adverse Effects ◽  
Pacific Northwest ◽  
Prunus Persica ◽  
Fruit Set ◽  
Fruit Size ◽  
Stone Fruits ◽  
Prunus Domestica ◽  
Peach Fruit ◽  
The Pacific ◽  
Spray Volume

Effects of Tergitol-TMN-6 surfactant on blossom thinning (fruit set), fruit quality, and yield were studied in different cultivars of peach (Prunus persica [L.] Batsch) during 2003 to 2005, and in one cultivar of nectarine Prunus persica [L.] in one orchard and one cultivar of plum (Prunus domestica [L.]) in two orchards in 2004. In addition to Tergitol-TMN-6, effects of Crocker's fish oil (CFO) alone in three peach cultivars or in combination with lime sulfur in a nectarine cultivar were studied on fruit set, quality, and yield. Tergitol-TMN-6 at 5 mL·L–1 or higher rates, applied at about 75% to 85% bloom, reduced fruit set without russeting peach fruit. Peach fruit size was often increased by Tergitol-TMN-6 treatment. Applications of Tergitol at 20 mL·L–1 or 30 mL·L–1 excessively thinned peaches. Tergitol-TMN-6 at all rates burned foliage, but the symptoms disappeared after a few weeks without any adverse effects on tree productivity. Tergitol-TMN-6 at 7.5 mL·L–1 or 10 mL·L–1, applied either once at about 80% to 85% bloom or twice at 35% bloom and again at 80% to 85% bloom, reduced fruit set without any fruit russeting in nectarine. Tergitol-TMN-6 at 7.5 mL·L–1 to 12.5 mL·L–1 reduced fruit set in `Empress' plum. CFO at 30 mL·L–1 was effective in blossom thinning of some peach cultivars. A combination of lime sulfur and CFO was not effective in blossom thinning of nectarine. Considering results from several orchards in different locations in the Pacific Northwest over 3 years, Tergitol-TMN-6 is an excellent blossom thinner for peach, nectarine, and plum at rates of 7.5 to 12.5 mL·L–1, sprayed at a spray volume of 1870.8 L·ha–1 when about 75% to 85% blooms are open.

scholarly journals Bloom Thinning `Loadel' Cling Peach with a Surfactant

1996 ◽  
Vol 121 (2) ◽  
pp. 334-338 ◽  
Author(s):  
Stephen M. Southwick ◽  
Kitren G. Weis ◽  
James T. Yeager
Keyword(s):  
Fruit Quality ◽  
Prunus Persica ◽  
Fruit Set ◽  
Fruit Size ◽  
Full Bloom ◽  
Akzo Nobel ◽  
Leaf Yellowing ◽  
Normal Hand ◽  
Spray Volume

Hand thinning fruit is required every season to ensure large fruit size of `Loadel' cling peach [Prunus persica (L.) Batsch] in California. Chemical thinning may lower costs of hand thinning. A surfactant, Armothin {[N,N-bis 2-(omega-hydroxypolyoxyethylene/polyoxypropylene) ethyl alkylamine]; AKZO-Nobel, Chicago; AR}, was sprayed at 80% of full bloom (FB), FB, and FB + 3 days. The spray volume was 935 liters/ha. Concentrations of AR were 1%, 3%, and 5% (v/v). An early hand thinning in late April, a normal hand thinning at 13 days before standard reference date (early May), and a nonthinned control were compared to bloom-thinned trees for set, yield, and fruit quality. AR resulted in no damage to fruit; however, slight leaf yellowing and burn and small shoot dieback were seen at the 5% concentration. Fruit set, and therefore, the number of fruit that had to be hand thinned, were reduced with 3% AR applied at 80% FB and 5% AR applied at all bloom phenophases (stages of bloom development). Thinning time was reduced by 37% (5% AR applied at 80% FB), 28% (5% applied at FB), and by 20% (3% applied at 80% of FB), compared to the normally hand-thinned control. Although AR resulted in early size (cross suture diameter and weight) advantages, at harvest there were no significant differences in fruit size among all AR treatments and the normally hand-thinned control. Total and salable yields of AR treatments and the normally hand-thinned control were equal. Armothin shows promise for chemical thinning of peach when used as a bloom thinner.

scholarly journals 952 PB 449 HYDROGEN CYANAMIDE ENHANCEMENT OF FRUIT SET

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 570c-570 ◽  
Author(s):  
Jason C. Powell ◽  
Calvin G. Lyons
Keyword(s):  
Detrimental Effect ◽  
Prunus Persica ◽  
Fruit Set ◽  
Fruit Size ◽  
Field Trials ◽  
The State ◽  
Fruit Crops ◽  
Labor Costs ◽  
Hydrogen Cyanamide ◽  
Insight Into

The state of Texas suffers from a lack of chilling one out of every five years. Reduced yield in temperature fruit crops such as peach (Prunus persica) is one detrimental effect associated withinadequate chilling. Field trials with hydrogen cyanamide (Dormex) have demonstrated that a one to two percent solution applied six weeks prior to bloom will substitute for inadequate chilling of up to 150 hours. Field trials with this chemical have provided further insight into some other possible benefits associated with its use such as: increased marketable yields of fruit crops, enhanced fruit size, and an earlier more concentrated harvest. Advantages noted by the use of this product include a possible earlier crop and reduced labor costs.

scholarly journals Phenology and reproductive traits of peaches and nectarines in Central-East Argentina

2009 ◽  
Vol 66 (6) ◽  
pp. 757-763 ◽  
Author(s):  
Norberto Francisco Gariglio ◽  
Marisa Mendow ◽  
Marcela Emilce Weber ◽  
María Alejandra Favaro ◽  
Diego Esteban González-Rossia ◽  
...  
Keyword(s):  
Prunus Persica ◽  
Fruit Set ◽  
Negative Relationship ◽  
Reproductive Traits ◽  
Reproductive Behaviour ◽  
Fruit Yield ◽  
Chilling Requirement ◽  
Flower Density ◽  
Chilling Hours ◽  
Fruit Harvest

In Santa Fe, the central-east area of Argentina, the expansion of fruit tree crops requires the introduction and evaluation of low chilling varieties. The aims of this study was to characterize the phenological behaviour and the reproductive traits of peach (Prunus persica L. Batsch) and nectarine varieties with chilling requirements ranging from 150 to 650 chilling hours (CH). Low chilling varieties (< 450 CH) had higher flower density (22.0-56.5 flowers m-1), fruit set (26.0-56.7%), fruit yield (9.3-36.6 kg per plant), and low coefficient of fruit yield variability than varieties with a higher chilling requirement (>500 CH). The phenology of high chilling requirement varieties had the advantage that blooming and fruit set happened after the period of late frost occurrence. However, they did not satisfy their chilling requirement, showing an inadequate vegetative and reproductive behaviour. Low chilling varieties began to sprout during July, and the period of full bloom occurred from July 14th to August 4th. Fruit harvest was initiated on October 19th with the cv. 'Flordastar' and it extended for 58 days. However, on low chilling varieties the harvest time was reduced in ten days. Flower density, fruit set and fruit yield showed a negative relationship with the chilling requirement of the variety.

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