Mechanical blossom thinning of apples and influence on yield, fruit quality and spur leaf area

2015 ◽  
Vol 95 (5) ◽  
pp. 887-896 ◽  
Author(s):  
Kendra A. McClure ◽  
John A. Cline

McClure, K. A. and Cline, J. A. 2015. Mechanical blossom thinning of apples and influence on yield, fruit quality and spur leaf area. Can. J. Plant Sci. 95: 887–896. Apple (Malus×domestica Borkh.) trees tend to crop heavily, which often makes crop load adjustment necessary. This can now be achieved as early as bloom by mechanical removal/thinning of blossoms. High-density Empire/M.26 and Royal Gala/M.26 apple trees were mechanically (MBT) and hand blossom thinned (HBT) in 2010 and 2011, respectively, and their effects on fruit set, subsequent hand thinning, final crop load, and spur leaf area were measured. In both years, MBT effectively thinned trees and reduced fruit set, but did not reduce the requirement for follow-up hand fruitlet thinning after June drop in 2011. In 2010, harvest yields for MBT treatments decreased, while weight and diameter increased. In 2011, most harvest and fruit quality parameters were unaffected by thinning. Trees that were mechanically thinned had significantly reduced spur leaf area, but were similar to unthinned control trees with respect to many of the yield and quality parameters measured. Mechanical blossom thinning is a new crop load management option for apple growers looking to supplement more traditional chemical and hand thinning techniques.

2020 ◽  
Vol 100 (2) ◽  
pp. 185-201 ◽  
Author(s):  
Michelle H. Cortens ◽  
John A. Cline

Gala apple (Malus domestica Borkh.) trees are prone to heavy cropping but respond to chemical fruitlet thinners to reduce crop load and improve fruit quality. Environmental concerns over the fate of the chemical fruitlet thinner carbaryl is widely acknowledged, but crop load management options are limited. In southern Ontario, Gala trees were treated with new thinning compounds or combinations to determine post-bloom thinning efficacy and resulting fruit quality. Treatments included 6-benzyladenine (6-BA) combined with naphthaleneacetic acid (NAA) or abscisic acid (ABA), and 1-aminocyclopropane-1-carboxylic acid (ACC) alone applied at 9 mm in 2014 and 17 mm in 2015. The treatment NAA + 6-BA produced unacceptably small “pygmy” fruit when applied at 17 mm fruitlet diameter. ABA at 150 and 300 mg L−1 and ACC at 150 mg L−1, when applied at 17 mm fruitlet diameter, resulted in acceptable fruit set, crop load, and quality results in comparison with the carbaryl thinner in 1 yr. The bioregulators ACC and ABA combined with 6-BA showed commercial potential for thinning Gala fruit but require further evaluation.


Author(s):  
J. Racskó ◽  
J. Nagy ◽  
Z. Szabó ◽  
M. Major ◽  
J. Nyéki

The effect of row direction (N-S, E-W), plant density (conventional and intensive) and rootstock (M9, MM106 and crab apple) on the sensitivity of 41 apple cultivars to sunburn injury was studied at 6 locations (Derecske, Kálmánáaza, Nagykutas, Nagylapos, Siófok, Tornyospálca). During the observations the cultivars had rootstock-specific properties in respect of sunburn-susceptibility. Accordingly, the injury was decreased in the order: M9, MM106 and seedling rootstocks. The differences in sensitivity depend on the canopy of trees, caused finally by the growing vigour of rootstocks. Accordingly, the highest value of sunburn injury was observed on M9 rootstock, because this rootstock has a dwarfing effect upon the scion cultivars. Thus, vegetative area of these trees grow very slowly and the foliage is not enough compact to protect the fruit from solar radiation. The size and density of the foliage increased in the order: M9, MM 106 and crab apple seedling as rootstock. Moreover, relationships were demonstrated between the diameter of upper part of the crown, the leaf area, the number of fruits per tree and the injury of sunburn. Authors categorized the cultivars in respect of values of sunburn incidence: 1. „Not sensitive", II. „Moderately sensitive" and HI. „Strongly sensitive" categories were constituted. Generally, Topaz and Gala cultivars showed low damage (or were free from symptoms), in contrast to this, Golden mutants suffered relatively much. The most sensitive cultivar was Jonica on all the three rootstocks. We searched for relationship between the fruit quality parameters and the frequency of sunburn. Significant correlation was found in the cases of fruit size and the extent of cover-colour. The latter is interpreted with the fact that the best coloured fruits are found on the periphery of crown as a consequence of more intense irradiation.


2016 ◽  
Vol 41 (3) ◽  
pp. 419-432
Author(s):  
MS Alam ◽  
N Islam ◽  
S Ahmad ◽  
MI Hossen ◽  
MR Islam

The study was carried out during summer of 2012 with BARI hybrid tomato 4, planted in the Olericulture farm of Bangladesh Agriculture Research Institute, Joydebpur, Gazipur, Bangladesh to find out the response of plants to some staking and pruning treatments on yield, fruit quality and cost of production. A two factor experiment consisting of three staking methods and four level of pruning, laid out in complete block design with three repetitions. Plants were staked on inverted „V? shaped staking, high platform and string. The plants were pruned to two stem, three stem, four stem and no pruning as control. Results showed that significantly the highest total number of fruits per plant (37.1), marketable fruits per plant (33.7), yield per plant (1.68 kg) and total yield (44.6 t/ha) were produced by the plants having the treatment string staking with four stem. The highest fruit set (43.50%) was found in the plants staking with string having three stems. Plants grown on string staking allowing two stem gave the maximum length (4.71 cm), diameter (4.83 cm) and weight (53.4g) of single fruit as well as maximum fruit firmness (3.43 kg-f cm-2). From the economic point of view, it was apparent that summer tomato produced by string staking with four stem pruning exhibited better performance compared to other treatment combinations in relation to net return and BCR (2.10).Bangladesh J. Agril. Res. 41(3): 419-432, September 2016


2021 ◽  
Vol 42 (4) ◽  
pp. 1085-1091
Author(s):  
A. Dash ◽  
◽  
D. Samant ◽  
D.K. Dash ◽  
S.N. Dash ◽  
...  

Aim: To evaluate the efficacy of foliar application of Ascophyllum nodosum extract, homobrassinolide, and triacontanol for improving fruit retention, yield, and quality in mango. Methodology: The experiment was laid out in a randomized block design with 10 treatments, comprising Ascophyllum nodosum extract (1000, 3000, and 5000 ppm), homobrassinolide (0.1, 0.3, and 0.5 ppm), triacontanol (1, 3, and 5 ppm), and water as control. Treatments were foliar sprayed at panicle initiation, pea, and marble stages of fruit growth. Observations were recorded on flowering, fruiting, yield, and fruit quality parameters. Results: All the treatments of Ascophyllum nodosum extract and triacontanol exhibited significant improvement in fruit retention, fruit weight, yield, and fruit quality parameters over control. However, 3000 and 5000 ppm Ascophyllum nodosum extract treatments outperformed all the treatments of triacontanol. Plants sprayed with 5000 ppm Ascophyllum nodosum extract recorded the maximum value for fruit retention (48.15, 36.74, 29.48, and 25.76% at 3, 6, 9, and 12 weeks after pea stage, respectively), number of fruits (133.25 per tree), fruit weight (188.84 g per fruit), and yield (25.16 kg per tree), whereas the lowest values were recorded under control. With respect to fruit quality, 3000 ppm ANE produced the fruits with the highest TSS (19.62 °B), whereas the highest TSS/acid ratio was recorded with 5000 ppm ANE (62.29) treatment. Interpretation: In mango, foliar application of Ascophyllum nodosum extract (3000-5000 ppm) thrice at panicle initiation, pea, and marble stages of fruit growth is effective for reducing fruit drop and enhancing quantum and quality of produce.


HortScience ◽  
1993 ◽  
Vol 28 (11) ◽  
pp. 1081-1084 ◽  
Author(s):  
Michael W. Smith ◽  
William Reid ◽  
Becky Carroll ◽  
Becky Cheary

Pecan [Carya illinoinensis (Wangenh.) C. Koch] fruit were thinned from `Mohawk' trees in Oklahoma and `Giles' trees in Kansas with a mechanical trunk shaker. All trees bore an excessive crop load before shaking. Fruit thinning improved the kernel percentage, individual nut weight, and kernel grade of `Mohawk', but nut characteristics of `Giles' were not affected by fruit thinning. Cold injury, caused by a sudden temperature drop in November, was positively related to the percentage of fruiting shoots in both cultivars. Fruit set in 1992 was negatively related to the percentage of fruiting shoots in 1991 in both cultivars. Consistent annual fruit set could be induced in `Giles' by fruit thinning, but return fruit set in `Mohawk', even at high levels of thinning, was low. Fruit thinning reduced yield the year of thinning in both cultivars. Thus, `Mohawk' trees should be thinned so that 50% to 60% of shoots bearing fruit at mid-canopy height would remain, and `Giles' trees should be thinned similarly to 65% to 70%.


2021 ◽  
pp. 203-213
Author(s):  
Rosemary J. du Preez

Abstract This chapter describes the guava fruit as well as the fruit set, growth, drop, harvesting, yield and quality (total soluble solids, total acids and ascorbic acid). Understanding the phenological cycle of guava and the effect of management practices on yield and fruit quality allows management practices to be modified to develop strategies which should lead to productivity gains for different pruning or chemical application times. As the effects of various treatments and times of application on yield and fruit quality for different cultivars and climatic zones are known, it is possible to decide on the optimum time to apply treatments knowing what the quality of the fruit will be, the time that the fruit will be harvested, expected yield and the critical times to apply management practices.


2017 ◽  
Vol 35 (2) ◽  
pp. 247-251
Author(s):  
Isabel Mourão ◽  
Luis M Brito ◽  
Luisa Moura ◽  
Maria E Ferreira ◽  
Sofia R Costa

Abstract Vegetable grafting is an increasingly used crop management strategy that aims to prevent soilborne biotic and abiotic stresses. For tomato crops, the number of stems per grafted plant determines planting density and crop exposure to sunlight. The effects of pruning grafted plants on yield and fruit quality have not been established, and this information is crucial to support decision-making by growers. A greenhouse experiment was run in the spring/summer season in the NW Portugal to assess the yield and quality parameters for grafted tomato plants (cv. Vinicio grafted onto Multifort rootstock) pruned to 2, 3 and 4 stems developed from the plant first nodes, or pruned to 2 stems developed from cotyledonary nodes, according to common practice. Total yield was significantly increased for the double-stemmed tomato plants, irrespectively of node origin (average yield 26.5 kg/m2), as compared to the 3- and 4-stemmed plants (average yield 19.5 kg/m2). These results can be explained by root system limitations to uptake water and nutrients coupled with the stronger competition between stems for the 3- and 4-stemmed plants. Fruit quality assessed through firmness (1.0 kg/cm2), soluble solids (5.1°Brix), acidity (1.0 g/100 g fresh weight), pH (4.4) and dry mater content (4.9%) was not affected by pruning systems. The greater yield obtained from double-stemmed plants offsets the increased planting and seedlings costs of using grafted tomato plants, particularly so for double-stemmed plants grown from first nodes, as they do not require intensive nursery care and are therefore less costly than those grown from cotyledonary nodes.


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