Summer Pruning Research Articles

Canopy factors influencing sunburn and fruit quality of Japanese plum (Prunus salicinaLindl.)

High irradiance and high temperatures decrease Japanese plum (Prunus salicina Lindl.) quality by causing sunburn. We manipulated orchard conditions to determine how resultant light and temperature affected fruit quality and sunburn. In the 2013/14 season, early summer pruning, late pruning and a no pruning control were applied in an ‘African Delight’ plum orchard trained to a staggered V trellising system in the Western Cape Province of South Africa. In 2014/15, 20% shade net was incorporated during the hottest part of the season in a split plot design. Shade net and a no shade net control formed the main plots while pruning treatments were subplots. Photosynthetic photon flux (PPF), fruit surface temperature (FST) and sunburn were progressively assessed on two hourly intervals on typically hot days for upper, mid and lower canopy positions. PPF and FST generally decreased from top to bottom of the canopy. Upper canopy positions had bigger and softer fruit with higher sunburn incidence and higher total soluble solids (TSS). Fruit that developed sunburn received >50% PPF of full sun on average while average FST exceeded 35°C. Early summer pruning improved early light penetration but enabled vegetative regrowth for filtered light during the hottest part of the season resulting in bigger and redder fruit with higher TSS and low sunburn. Delayed pruning increased sunburn with no increase in fruit size, while the control delayed fruit maturity and reduced fruit size. The shade net reduced sunburn caused by delayed summer pruning. While it was apparent that proper timing of orchard light manipulation is essential, the use of shade net still has to be evaluated over the entire growing season to ascertain its full value.

‘Gala’ apple performance with mechanical hedging in southern Brazil growing conditions

Different canopy management strategies have been used to reduce vigor and labor costs, including time of pruning and training system. “Fruiting wall” systems lend themselves to mechanical hedging, to control vigor and reduce labor costs. Hedging could eliminate the need for summer pruning. This trial evaluated different hedging times during the summer and different hedging intensities in a Brazilian orchard located at Vacaria-RS (-28,44 S; -50,85 W) on cultivar 'Maxi Gala' grafted on M.9 rootstock, planted in 2009, at ca 3,570 trees ha(-1), trained as tall spindle. Trees were hedged in 2014/15 at one intensity; in 2015/16 the same intensity used in 2014/15 was compared to a heavier one. The intense hedge uniformly narrowed the trees to 90 cm thick; the less intense narrowed the trees 120 cm thick at the base, 100 cm in the top. Hedging was applied at four different times during the southern summer: first weeks in December, January, February, March. Unpruned trees served as control. The lighter hedging in 2014/15 did not cause regrowth in any of the 4 treatment times. Yield was not affected in both years for the lighter pruning, while it was reduced in the intense hedge in 2015/16 if pruning were done in December. Fewer fruit dropped in the intense hedge in January than in December. Further observations need to be carried out, namely on growth, vigor and return bloom.

Nitrogen Distribution in Annual Growth of 'Italia' Table Grape Vines.

Little information is available about nitrogen (N) content and its concentration in table grape vines. Knowledge of the quantity of N accumulated by the vine organs during the season could support sustainable fertilization programs for table grape vineyards. The aim of the present study was to determine the N content and its concentration in different annual organs, including summer and winter pruning materials, clusters at harvest, and fallen leaves at post-harvest. Specifically, biomass and N were analyzed at six phenological growth stages (flowering, berry-set, berry growth, veraison, ripening, and harvest) from 2012 to 2015. Nitrogen concentration was highest (>40 g/kg d.w.) in the leaves of the secondary shoots at flowering, whereas values >30 g/kg were measured in the leaves of the primary shoots. Nitrogen concentration in the clusters at harvest was 5.3–7.6 g/kg with an accumulation of 18.6–25.4 g/vine in the seasons. The decrease of N content in the primary leaves after flowering indicated a remobilization toward the clusters, which acted as a stronger sink. Later in the season (veraison-ripening), leaves translocated N to permanent organs and primary stems. Pruned wood and fallen leaves accounted for the largest N removal from the vine after clusters, 6.0–7.9 and 9.2–10.2 g/vine, respectively. With regard of the vine annual biomass, the growth followed a sigmoidal model reaching 7300–7500 g of d.w./vine at harvest. Vine leaf area, including both primary and secondary leaves, peaked at veraison (17–21 m2). Vines accumulated ≅35 g/vine of N at harvest, not considering the N removed with the intense summer pruning practices (≅7 g/vine) and the fraction mobilized toward the storage organs (10–15 g/vine). The overall N required by the vine was around 50–55 g/vine, which corresponded to ≅80 kg of N/ha in a vineyard with 1500 vines and a yield of 40 t/ha. Summer and winter pruning practices removed 29–31 g/vine of N which will be partly available (to be considered in the fertilization schedule) for the vine in the successive years if pruned residues were incorporated and mineralized in the soil.

Evaluation of biometric parameters of ‘Belona’, ‘Guara’ and ‘Lauranne’ cultivars in a superhigh density orchard

In Portugal, the first almond superhigh density (SHD) orchard was planted in 2012. The trees were trained to obtain a hedge with dimensions controlled to allow the use of over-the-row machinery for harvesting. In this orchard most of the cultivars used, are from foreign almond breeding programs. Although the lack of knowledge about the behaviour of almond cultivars in SHD orchard, a lot of new plantations were made. This study shows some biometric parameters of 3 almond cultivars registered in the first season after plantation. The SHD orchard was established in September 2014 at the Herdade da Torre das Figueiras, Monforte, Portalegre, Portugal (39°04’N; 07°29’W). The orchard is planted in a 5×1,5 m array with East-West orientation. ‘Belona’, ‘Guara’ and ‘Lauranne’ were the cultivars used in this study. In each cultivar, 3 lines of 93 trees were randomly selected. From each line, 3 plots of 10 trees were randomly chosen in order to measure biometric parameters. In April 2015, July 2015 and March 2016 the following measurements were made: trunk diameter, tree height, height and width of the canopy. Green pruning intervention was performed by the farmer in July and September 2015 to control canopy dimension and to increase the number of shoots inside the canopy. It consisted in mechanically topping the canopy parallel to the ground and hedging each side of the canopy. These measurements allow to verify that ’Lauranne’ registered the higher trunk diameter and canopy dimension before summer pruning. Summer pruning seems to be an efficient solution to get an adequate canopy for the harvesting machine.

Primary productivity and physiological responses of Vitis vinifera L. cvs. under Free Air Carbon dioxide Enrichment (FACE)

Abstract Two Vitis vinifera L. cultivars, Riesling and Cabernet Sauvignon, were grown in the Geisenheim VineyardFACE (Free Air Carbon dioxide Enrichment) system under rain-fed conditions to investigate the effects of elevated CO2 on the productivity of grapevines for three consecutive years (2014–2016) following planting in 2012. The FACE system consisted of six 12 m diameter rings, with three at ambient CO2 (aCO2, 400 ppm), and three rings at elevated CO2 (eCO2, + 20% of aCO2 level). Vegetative growth, single leaf gas exchange and yield parameters were monitored for the three growing seasons. Vegetative growth parameters responded differently to CO2 treatments depending on biomass components. Trunk cross section area, as an indicator of perennial growth, showed a significant increase for Riesling under eCO2 but not for Cabernet Sauvignon. Fresh biomass as lateral leaf area and fresh weight of summer pruning were stimulated by elevated CO2 for both cultivars. Leaf gas exchange measurements for both cultivars showed a significant increase in net assimilation rate and an improved intrinsic water use efficiency for all three years under eCO2 conditions. However, contrary to expected stomatal behaviour of grapevines, transpiration rate and stomatal conductance were higher under elevated CO2 for Riesling and Cabernet Sauvignon in all three seasons. Higher values of pre-dawn leaf water potential recorded under eCO2 point towards an interaction with soil water availability and root system development. Elevated CO2 resulted in higher yield in terms of higher bunch weight, but did not affect average number of bunches per vine or sugar content of must at harvest date. Accordingly, bunch architecture was altered under elevated CO2 levels. The increase in primary productivity of grapevines under eCO2 indicates yield gains that can be expected under even modest near-future CO2 scenarios. However, higher water use, particularly if maintained as grapevines transition to maturity, may have critical implications for the future adaptation of non-irrigated viticulture to increasing temperature and periods of rainfall deficit.

Impact of simulated mechanical hedge pruning and wood age on new shoot demography and return flowering in olive trees

More vigorous watersprouts and fewer low vigor shoots form as wood age increases at the cutting points with greater canopy pruning depth in olive trees, which reduces return flowering. Such information is relevant to long-term olive orchard pruning strategies in hedgerows. Demographic analysis of growth responses to pruning in fruit trees seeks the quantification of the typology of new shoots originating from the remaining branches. Pruning of hedgerows using mechanical discs is becoming increasingly common in orchards, but little information is available as to how such pruning, which does not discriminate between branch size, wood age at the cutting point, branch type, or position, modifies subsequent new shoot demography. Hence, the experiment described in this study in young olive trees (cv. Arbequina) assessed the following questions: (1) Is the type and growth of new shoots associated with the intensity of mechanical pruning and/or the wood age on which they grow? (2) How many growing seasons does it take for new shoots formed after pruning to flower? The principal hypothesis was that a greater proportion of vigorous watersprouts form compared to low vigor shoots as wood age at the cutting points increases with canopy pruning depth, and that the watersprouts have low flowering potential. Both new shoot growth and return flowering were monitored on exposed supporting wood over several growing seasons after implementing three winter (25W, 50W, and 75W) pruning levels of increasing intensity and one summer pruning (75S) treatment along with an unpruned control (CON). As hypothesized, a greater number and elongation of vigorous watersprouts were found as wood age increased at the cutting points with greater winter pruning intensity, and the watersprouts had low levels of return flowering even 3 full years after pruning compared to the CON. Growth of low vigor shoots was relatively more important than watersprout growth in the severe summer pruning treatment, although 3 years after the summer pruning flowering was not fully recovered. In contrast, the more lightly pruned winter treatments (25W, 50W) did not show significant differences in flowering with the CON at the end of 3 years. Thus, mechanical hedge pruning in olive trees should be light-to-moderate to avoid the formation of watersprouts on older wood, which leads to long-term reductions in flowering.

RELATIVELY SAFE TREATMENTS (PARTIAL / COMPLETE COVERAGE SPRAY) FOR THE CONTROL OF SCOLYTUS AMYGDALI (COLEOPTERA: SCOLYTIDAE) IN APRICOT ORCHARDS IN EGYPT

Anew relatively safe and commercial partial/complete coverage spray to control Scolytus amygdali (Coleoptera: Scolytidae) in the apricot orchard (applied only twice instead of 6 current MOA recommended chemical treatments/season) at El- Kattatba district, (Menofia Governorate). Percentages reduction of infestation for the following 7 applications for one-year treatment (2015), two successive years (2015 and 2016), and three successive years (2015, 2016 and 2017) were, respectively, as follow: A: Horticultural treatments: 1) dormant winter pruning (27.73 increased to 34.87 then 38.88%), 2) summer pruning (15.06 increased to 17.65 then 19.24%), 3) dormant and summer pruning (34.06 increased to 39.50 then 45.69%). B: Chemical treatment: 4) MOA recommended chemical treatments (3 treatments during spring and 3 treatments during autumn) (80.57 increased to 85.08 then 89.58%), 5) new commercial partial/complete coverage chemical treatments (1 treatment during spring and 1 treatment during autumn) (61.35 increased to 71.01 then 79.16%). Third: Horticultural (winter and summer pruning as an additive control) together with chemical treatments: 6) pruning together with MOA recommended treatments resulted in 86.03% increased to 88.24% then 96.39%, and 7) pruning together with new partial/complete coverage treatment resulted in 68.78% increased to 78.15% then 91.78%. The new commercial and relatively safe partial/complete coverage chemical control eliminates the pesticide use (2 treatments insteat of 6) and reduces residues, prevent the outbreaks of secondary species, decrease the environmental pollution, encourage the role of the biological control agents and obtain better production of decontamination of fruits through using limited insecticides.

Influence of the pruning system on the growth and productivity of slender spindle apple trees

Slender spindle is currently the most widespread pruning system for apple trees in the Czech Republic. However, further modifications of this pruning system have been developed. In this study, two pruning systems were compared in the years 2012 to 2015: slender spindle and modified slender spindle (characterised by ‘click’ pruning). The pruning systems were validated on three varieties, using either winter pruning or winter pruning supplemented with late summer pruning in August. The studied parameters included the average length of annual shoots, increase of trunk cross-sectional area (ITCA), fruit yield per tree, specific yield, average fruit weight, number of fruits and their size in various parts of the tree crown, the number of interventions by pruning and the total weight of the removed biomass. There were no significant differences in most of the parameters mentioned above. Application of the ‘click’ pruning technique over several years significantly increased the number of cuttings but the total biomass removed was lower compared with traditional slender spindle.

Effect of leaf removal on grape and wine composition in ‘Merlot’

The adaptation to climate change requires the adjustments of viticultural practices, particularly changing the fruit to leaf area ratio which could be an effective option to maintain and enhance fruit and wine quality. Fruiting capacity and berry composition of grapevine are dependent on canopy area, with grapevine carbohydrate reserves affected by the crop load. 'Merlot' grapevines grown in the experimental vineyard of the NWGIC (South Eastern Australia) received treatments that altered the leaf area/fruit ratio. These received severe summer pruning (SSP), upper (ULR) and lower leaf removal (LLR) implemented at pea size during two growing seasons. Generally, all treatments lowered total soluble sugars, but the total sugar yield was not altered, also the total anthocyanins and phenolics of the berries did not differ at harvest. The titratable acidity and alcohol concentration of the wine was influenced by the change of the canopy size as were sensory attributes. Particularly, wines made from grapes of the SSP treatment were different in most attributes compared to wines that were made from grapes of untreated vines. The overall response of partial defoliation and severe summer pruning conducted prior to veraison suggests that it can be used as a management practise to alter berry ripening speed and grape composition, consequentially influencing wine attributes. However, depending on position, intensity and time the impact of such treatments on carbohydrate reserves in the perennial structure may have long-term implications.

Training Systems for Cold Climate Interspecific Hybrid Grape Cultivars in Northern Climate Regions

Training systems influence grapevine (Vitis sp.) size, shape, and canopy architecture, which ultimately affects yield and fruit composition. Cold climate interspecific hybrid grapes (CCIHG) have propelled the creation of a new and fast-growing grape and wine industry in the northeast and upper midwest of the United States. This study evaluated the effect of three training systems: high cordon (HC), midwire vertical shoot positioning (VSP), and modified Scott Henry (SH) on vine growth, yield, and fruit composition of four CCIHG cultivars, Brianna, Frontenac, La Crescent, and Marquette, during two growing seasons. The divided canopy training system SH increased the crop yield per meter of row in all cultivars relative to HC and VSP, despite reduction in crop size imposed by crop thinning in vines trained to SH. VSP-trained vines had lower yields compared with HC, and this was most evident during the second year of the study, as vines were still being trained when the study commenced. Despite the higher crop size associated with vines trained in a SH system, there were minimal differences in fruit soluble solid concentration (SSC), titratable acidity (TA), and pH at harvest time. No differences were observed in vine size, expressed as dormant cane pruning weights, among training systems possibly because of the control of vegetative vigor, especially in VSP-trained vines, through shoot positioning and summer pruning. CCIHG cultivars appear to have the capacity to support higher yields under SH and HC systems without compromising fruit quality; however, labor requirements involved in establishing and maintaining more complex training systems should be considered when selecting a training system for CCIHG cultivars.

Pruning practices influence infection and dissemination of Calosphaeria pulchella, the cause of Calosphaeria canker of sweet cherry

Calosphaeria canker of sweet cherry, caused by Calosphaeria pulchella , is a limiting factor for sweet cherry production, but the role of pruning practices on pathogen dissemination remains unknown. Three experimental treatments were compared during summer and winter seasons, to assess their effects on pathogen transmission. The treatments were: i) using disinfected pruning shears; ii) pruning shears used to cut through diseased branches before each subsequent cut (non-disinfected pruning shears); and iii) artificial inoculation of fresh pruning wounds with C. pulchella . Six months after pruning, branches were cut from trees for disease assessment and fungal isolation. Pruning with non-disinfected pruning shears increased disease incidence and severity, compared with the use of disinfected shears. Artificially inoculated branches gave the greatest disease incidence and severity. Results from the various treatments were consistent for both winter and summer pruning. These confirm that frequent disinfection of pruning tools is advised for the effective management of Calosphaeria canker of sweet cherry.

The Effects of Some Summer Pruning and Humic Substance Applications on The Nutritional Value of ‘Alphonse Lavallée’ Grape Cultivar

Viticulture is an important agricultural branch in Turkey. Grape is the most grown fruit species in Turkey. The study was conducted with ‘Alphonse Lavallee’ grape variety (Vitis vinifera L.) grown on grafted 1103 Paulsen rootstock in Turkey in 2016. In the study effects of Control (C), 1/3 Cluster Tip Reduction (1/3 CTR), Shoot Tip Reduction (STR), Humic Substance Application (HS), 1/3 CTR + STR, 1/3 CTR + HS, STR + HS, 1/3 CTR + STR + HS applications on nutritive values were investigated. According to results; the maximum dry matter content 87.64 g/100 g with HS, 87.76 g/100 g with 1/3 CTR + HS, 87.78 with STR + HS and 87.67 with 1/3 CTR + STR + HS applications; the maximum crude protein 3.38 g/100 g with HS and 3.40 g/100 g with STR + HS applications; the maximum crude cellulose 4.46 g/100 g with HS application; the maximum total sugar content 64.64 g/100 g with STR and 64.64 g/100 g with HS applications were obtained. No statistically significant difference was found in terms of crude ash content.

The Effects of the Summer Pruning Operations on the Winter Buds Productivity of cv. Vranec (Vitis vinifera L.)

The study presents the analysis of the influence of summer pruning operations (defoliation, cluster thinning) on the parameters of a potential productivity of winter buds at the vine variety Vranec grown near Veles in the period 2013-2015. For this research, four treatments were set: control, defoliation and two types of cluster thinning: 10 and 6 clusters per vine. From the obtained results it is found that there are no injuries in the main winter buds during the vegetation period and the potential fruitfulness is determined by higher coefficient, 1.38, which depends on the location along the cane. The yield at this variety will be formed mainly by clusters with size of 350-550 μm, followed by those with the length of 550-750 μm. The application of defoliation and regulation of the vine yield has a beneficial effect on increasing the rate of potential fruitfulness of winter buds, the number of buds with 2 and 3 clusters, increasing the inflorescences with a length of 350-550 μm and the appearance of those longer than 750 μm.

Effect of Summer Pruning and Some Bio-Stimulants on Bud Fertility, Vegetative Growth, Yield and Fruit Quality of Vitis vinifera cv. "Superior" Grapevines

Effect of Summer Pruning and Some Bio-Stimulants on Bud Fertility, Vegetative Growth, Yield and Fruit Quality of Vitis vinifera cv. "Superior" Grapevines

Grapevine quality: A multiple choice issue

Abstract Over decades, the concept of grape quality has evolved emphasizing its multidisciplinary nature and that the same “desired quality” might correspond to even strikingly different compositional patterns. The review takes a long journey throughout the multiple factors impinging on grape quality, not excluding also sections devoted to table grapes. It starts with a through survey on the genetic factors influencing grape quality focusing on diversity in different compositional traits (sugar, organic acid, pH, phenolics and aromas) relating to cultivars and clones. Then, most recent knowledge about the effects of soil characteristics, nutrients, light, temperature and water availability, as standalone factors or in interaction, on grape quality are summarized. The more applied section of the review introduces the very much debated yield-quality relationship that, over years, is being interpreted with more flexibility and with greater consensus for an “optimal yield range” that within a given context can anyway reach the desired quality. The impact of the main summer pruning operations (leaf removal, shoot and cluster thinning, shoot trimming) is reviewed and special care taken to highlight most recent contributions with adjusted summer pruning developed to either adapt to climate change issues or to induce specific composition patterns. Review ends with a quick survey on methods nowadays available for fast, non-destructive grape composition assessment.

Factors Affecting Quality and Health Promoting Compounds during Growth and Postharvest Life of Sweet Cherry (Prunus avium L.).

Sweet cherries are attractive fruits due to their taste, color, nutritional value, and beneficial health effects. Sweet cherry is a highly perishable fruit and all quality attributes and the level of health promoting compounds are affected by growth conditions, picking, packing, transport, and storage. During production, the correct combination of scion × rootstock will produce fruits with higher firmness, weight, sugars, vitamins, and phenolic compounds that boost the fruit antioxidant activity. Orchard management, such as applying drip irrigation and summer pruning, will increase fruit sugar levels and total phenolic content, while application of growth regulators can result in improved storability, increased red coloring, increased fruit size, and reduced cracking. Salicylic acid, oxalic acid, acetylsalicylic acid, and methyl salicylate are promising growth regulators as they also increase total phenolics, anthocyanins, and induce higher activity of antioxidant enzymes. These growth regulators are now also applied as fruit coatings that improve shelf-life with higher antioxidant enzyme activities and total phenolics. Optimizing storage and transport conditions, such as hydro cooling with added CaCl2, chain temperature and relative humidity control, are crucial for slowing down decay of quality attributes and increasing the antioxidant capacity. Application of controlled atmosphere during storage is successful in delaying quality attributes, but lowers ascorbic acid levels. The combination of low temperature storage in combination with modified atmosphere packaging (MAP) is successful in reducing the incidence of fruit decay, while preserving taste attributes and stem color with a higher antioxidant capacity. A new trend in MAP is the use of biodegradable films such as micro-perforated polylactic acid film that combine significant retention of quality attributes, high consumer acceptability, and a reduced environmental footprint. Another trend is to replace MAP with fruit edible coatings. Edible coatings, such as various lipid composite coatings, have advantages in retaining quality attributes and increasing the antioxidant activity (chitosan) and are regarded as approved food additives, although studies regarding consumer acceptance are needed. The recent publication of the sweet cherry genome will likely increase the identification of more candidate genes involved in growing and maintaining health related compounds and quality attributes.

Summer pruning and reflective film enhance fruit quality in excessively tall spindle apple trees

Tall spindle planting systems achieve high-quality fruit from plants that flower early and sustain a high yield. While some growers in Korea let apple trees grow up to 4 m or higher in high-density planting systems with M.9 rootstock to produce more fruits, such practices lead to very tall trees with low-quality fruit that develop in the lower canopy. To minimize this effect, we used the ‘Hongro’ cultivar to examine the effect summer pruning and installation of reflective film had on fruit size and quality in the lower canopy. We measured light distribution, diameter of flower buds, fruit quality, and leaf physiological characteristics at different parts of the canopy of trees that were treated with summer pruning (SP) and the installation of reflective film (RF), compared to those allowed to maintain their dense canopies (unpruned control; UC). The SP + RF treatment improved the overall light availability throughout the canopy and increased the amount of light by approximately 25% in the lower parts of the canopy compared to that in the UC group. The SP + RF treatment increased size, color, and soluble solids content in fruits from the lower parts of the canopy. Moreover, this treatment increased leaf photosynthetic activity, specific leaf weight, and flower bud diameter. Therefore, summer pruning and the installation of reflective film helps light penetration in excessively tall spindle trees and improves fruit quality in a high-density apple production system.

Early results of tree training system on production of two apple cultivars

A field planting of 'Daybreak Fuji'/M.9 NAKB T337 and 'Rubinstar Jonagold'/B.9 was established in 2008 to evaluate 4 training systems: tall spindle (TS), vertical axis (A), tall trellis (TT) and minimally pruned (MP). Training system influenced the number of flowers and flowering density in the second and third growing seasons. At the end of the 6th growing season there was no influence of training system on tree size for 'Jonagold' (JG), while 'Fuji' (DF) TT trees were the smallest of the 4 systems. Total cumulative yield for both cultivars was greatest for trees trained to the MP system. Total cumulative yield for 'Fuji' was lowest for trees trained to the TT system. Cumulative efficiency for 'Jonagold' was significantly better for the trees in the TT and MP than trees in the TS system. There was no significant difference in cumulative efficiency for 'Fuji' trees in any system. Total number of fruit tree-1 was higher for MP trees resulting in lower fruit weight. Labor requirements, man h ha-1, were consistently higher for the TT system largely due to summer pruning; while it was consistently lower for the MP system. Light intensity in the lower canopy in 2012 was not influenced by training system for JG but was for DF.

Can we manage light interception levels above 70% in apple orchards?

For the last 20 years we have recommended that orchards be designed to intercept a minimum of 70% light interception. Replicated field plantings at Geneva have shown that when tree height is about 90% of the between row spacing light interception is about 75%. This has become our standard recommendation in designing new orchards. However, in recent years three developments have led us to question this rule. First the development of the Tall Spindle planting system and the use of mechanical summer pruning has resulted in very narrow canopy profiles (fruiting walls), which have very good light distribution within the canopy. This could allow taller trees relative to the between row spacing with a height to row spacing ratio of 1:1. A second development has been the use of V-shaped canopies, which are very thin and shoot growth in the middle of the V is controlled with plant growth inhibitors. These V-shaped canopies can intercept more than 75% of available light depending on the open gap at the top of the V. This tree shape allows even the lowest part of the canopy to receive adequate light during the middle of the day with good fruit quality in the bottom of the canopy but also imposes the greatest energy load on the tree and hence transpiration compared to vertical tree shapes. A third trend is the use of reflective films to enhance the light exposure level of the lower part of the canopy. This practice with the use of V-shaped canopies could utilize 80-85% of available light energy resulting in higher yield.

Comparison of Two Training Methods Applied to Apple Trees Trained to Slender Spindle During the First Years After Planting

The research was focused on the comparison of two pruning methods (winter pruning and winter + summer pruning) applied to apple trees trained to a standard and a modified slender spindle. The orchard of ‘Topaz’ trees, grafted on rootstock M 9, was planted in spring 2011. In the years 2013 – 2016, trunk cross sectional area (TCSA), crown volume, cumulative yields, yield efficiency, relative proportion of fruit size classes, number of cuts and dry matter of pruned wood were analyzed. The total growth intensity of the trees, measured by TCSA, was similar among the treatments. The trees of modified slender spindle had lower mean crown volume (2.751 – 2.765 m3) comparing to slender spindle with additional summer pruning (3.355 m3) and proved to better control the tree size. The modified slender spindle brought similar or slightly lower cumulative yields, but significantly higher proportion of good sized fruits (in categories above ř 70 mm) comparing to slender spindle. The pruning of modified spindle brings generally higher number of cuts removing a higher amount of woody biomass in comparison to slender spindle, regardless if combined with summer pruning. The additional summer pruning brought no beneficial effect in reduction of growth, fruit production and fruit size of the modified slender spindle.