Trunk Cross-sectional Area Research Articles

Effects of Tree Spacing and Branch Configuration on Production, Fruit Quality, and Leaf Minerals of ‘Aztec Fuji’ Apple Trees in a Tatura Trellis System Over 5 Years

Tree spacing and branch architecture are critical for the productivity of high-density orchards. The influence of two tree spacings of 45.7 cm × 366 cm and 91.4 cm × 366 cm each with two branch architectures or configurations of shortened branch (ShBr) or overlapped branch (OverBr) on tree growth, yield components, fruit quality, and leaf mineral nutrients in an ‘Aztec Fuji’ apple (Malus domestica Borkh.) orchard with a 60-degree Tatura trellis (V) system was studied over 5 years. Trees planted with 91.4-cm spacing had a significantly greater trunk cross-sectional area (TCSA), higher number of fruit and greater yield per tree, and greater cumulative yield efficiency than those of trees planted with 45.7-cm spacing during 2012–16. Tree spacing did not significantly affect fruit weight and firmness at harvest or after storage. However, trees planted with 91.4-cm spacing always had higher fruit color, sunburn, fruit russet, and watercore at harvest and a higher soluble solids concentration but lower fruit bitter pit at harvest and after storage compared to those of trees with 45.7-cm spacing. These differences were often significant. Trees with 45.7-cm spacing had significantly higher leaf concentrations of potassium, iron, copper, and manganese and relatively higher leaf zinc than those of trees with 91.4-cm spacing. Trees trained according to ShBr architectures had a relatively larger TCSA than those of trees with an OverBr configuration every year. Branching architectures did not affect the number of fruits per tree, yield per tree, yield per hectare, yield efficiency, or biennial bearing index in any year. Trees with a ShBr architecture had significantly larger fruits than those with an OverBr system every year and over the 5 years. Trees with a ShBr architecture had higher average leaf fresh and dry weights and calcium concentration but a similar percentage of dry weight compared to those of trees with an OverBr architecture.

Comparative study of five scab resistant apple cultivars

Vegetative and reproductive characteristics of five resistant apple cultivars budded on ‘М9-Т337’ rootstock were compared in the intensive orchard, planted at the density of 2380 trees per hectare (3.5 × 1.2 m) in the period 2017-2023. Trees were formed as tall spindle, under an insecticidal net against hail. Trees were grown under drip irrigation and sod-mulch system was applied. The cultivars FUJIONpbr and ENTERPRISE demonstrate greater trunk-cross section area, higher trees and greater crown volume to the tested cultivars. The smallest trees were noted in Cultivar GEMINI*. The lowest yield per unit area was obtained on cultivar FUJIONpbr. There was no significant difference among other cultivars. Despite of generally good characteristics the cultivar GEMINI* has relatively small fruits. Keywords: apple, vigor, productivity, fruit weight, yield

Pre-Plant Soil Treatments Influence Tree Performance and Nematode Dynamics in Replanted Cherry Orchards.

In this two-year field study, the impacts of pre-plant soil management strategies, including soil fumigation, nematicide application, and organic amendments, on the growth and nematode community dynamics on cherry cultivars 'Emperor Francis' and 'Ulster' grafted to 'Mahaleb' rootstock were investigated in a replanted orchard site. In the first year, fumigation with 1,3-dichloropropene - chloropicrin mixture (Telone C-35) led to significantly increased trunk cross-sectional area and canopy height in both cultivars. Pratylenchus penetrans population densities were suppressed only short-term. Plots treated with the fungicide/nematicide fluopyram (Velum® Prime) had P. penetrans reproduction factors below one throughout both years independent of the scion. Additionally, the combined application of Seed Starter 101®, Dairy Doo® compost, and straw mulch reduced the reproduction factor of P. penetrans to below one in the first year. In the same time period, this combinatory treatment had the highest reproduction factor for bacterivore and fungivore nematodes. Based on results of this study, fumigation with Telone® C-35 resulted in improvement of tree establishment and provided effective short-term suppression of P. penetrans. Velum® Prime exhibited longer-term efficacy for the suppression of P. penetrans.

Phenological, Morphological and Pomological Characteristics of ‘Samsun Güzeli’ Pear Genotype on BA29 Rootstock

Türkiye has many local pear cultivars; some of them do not have much production and propagation potential due to their low quality and undesirable vegetative and generative characteristics. However, those that are superior in terms of fruit quality and yield characteristics have found a place for themselves in both local and national markets. In this respect, the ‘Samsun Güzeli’ genotype, which is an important local cultivar, is an ideal cultivar with many features and has a high potential to spread its cultivation all over Türkiye and other countries. ‘Samsun Güzeli’ is an autumn genotype, can easily meet the high demand in local and international markets due to its attractive color, smooth fruit shape and high quality. Despite all these valuable features, this cultivar is still not well known in Türkiye. There is a great need to disseminate cultivation and research on this subject. This study mainly aimed to reveal the phenological, morphological and pomological characteristics of the ‘Samsun Güzeli’ local pear genotype grafted on BA29, a commercially traded rootstock in 2021-2022. The results showed that the ‘Samsun Güzeli’ pear genotype completed its phenological cycle in 255 days in 2021 and 228 days in 2022 in Samsun climatic conditions. Fruit set rate of the genotype was 12.05% and the average yield was 17306.23 kg ha-1. It was also determined that the morphological characteristics averages were as the following; rootstock diameter 76.71 mm, trunk diameter 61.97 mm, trunk cross-sectional area 34.06 cm2, tree height 253.12 cm, canopy volume 0.96 m3, annual shoot length 37.19 cm and leaf area 11.74 cm2. Averages values of pomological and chemical properties recorded as the following; fruit weight 114.60 g, fruit volume 109.90 ml, soluble solid content (SSC) 13.16%, acidity 0.33%, and pH 4.37. In the sensory evaluations, the highest scores were obtained by juiciness (6.32) in the year 2022 while scores of overall visual quality were lowest in both years. In conclusion, it can be said that the ‘Samsun Güzeli’ genotype performs adequately in terms of fruit yield and quality on the standard dwarf rootstock and conducting new studies might be beneficial to disseminate the genotype.

Differentiated In-Row Soil Management in a High-Density Olive Orchard: Effects on Weed Control, Tree Growth and Yield, and Economic and Environmental Sustainability

Two different in-row soil management techniques were compared in the Olive Orchard Innovation Long-term experiment of the Council for Agricultural Research and Economics, Research Centre for Olive, Fruit, and Citrus Crops in Rome, Italy. Rows were managed with an in-row rotary tiller and with synthetic mulching using permeable polypropylene placed after cultivar Maurino olive trees planting. The effects of the two treatments were assessed through weed soil coverage and the growth of the olive trees. Results showed better agronomic performance associated with synthetic mulching. The weed control effect along the row of a young high-density olive orchard was higher with the synthetic mulching compared to hoeing. The effect of the synthetic mulching seemed to disappear when removed from the ground (spring 2023) since no significant differences were found for tree size and yield in the two tested in-row soil management systems at the end of 2023. Finally, the growth of the young olive trees (Trunk Cross Sectional Area, Height, and Canopy expansion) measured across the three years, was higher for the synthetic mulched row than the hoed one. The use of synthetic mulching along the row positively forced the vegetative growth of the young olive trees and anticipated the onset of fruit production compared to periodical hoeing: a significantly higher fruit production was registered three years after planting. Root diameter was higher under synthetic mulching one year after planting, and no differences were observed in the following sampling dates showing similar fluctuations linked to the seasonal growth pattern. The life cycle assessment and costing highlighted that the application of mulching had a higher eco- and economic-efficiency than the periodical in-row soil hoeing.

Adaptation of Almond Cultivars in Majorca Island: Agronomical, Productive, and Fruit Quality Characteristics

Almond cultivation has a long-standing tradition on the island of Majorca, traditionally practiced under rainfed conditions. Currently, new plantations are established with irrigation; however, due to present conditions and the impacts of climate change, water availability is limited. The Government of the Balearic Islands permits a maximum water supply of 3000 m3 ha−1 per year for almond cultivation. In this study, a 6-year field trial was conducted to investigate the adaptation of fourteen almond cultivars obtained from different research centers under deficit irrigation practices in the soil and climatic conditions of Majorca Island. The cultivars had a significant effect on trunk cross-sectional area TCSA, cumulative almond in-shell yield, cumulative kernel yield, yield efficiency, and shelling percentage. The ‘Marta’ and ‘Tarraco’ cultivars exhibited the highest TCSA values. Regarding cumulative almond in-shell yield, ‘Glorieta’ and ‘Constantí’ produced the highest yields, whereas the lowest yields were observed in ‘Mardía’ and ‘Tarraco’. In terms of shelling percentage, ‘Ferragnès’ exhibited the highest value. Kernel quality parameters were cultivar-specific. Additionally, oleic acid content was strongly negatively correlated with linoleic acid content. All cultivars exhibited an unsaturated fatty acid content exceeding 90%, with ‘Masbovera’ showing the highest value.

Architectural approach to evaluate the design and management of almond cultivars suitable for super high-density orchards.

The almond tree is a major global nut crop, and its production has surged dramatically in recent years. Super high-density (SHD) planting systems, designed to optimize resource efficiency and enhance precocity, have gained prominence in almond cultivation. A shift in cropping systems toward sustainable intensification (SI) pathways is imperative, and so maximizing branching density within the canopies of SHD trees is crucial to establish and maintain productive potential, especially for hedge-pruned trees. This study investigates the influence of different almond cultivars grafted onto a novel growth-controlling rootstock on tree architectural and growth parameters in a SHD orchard. This open field research provided valuable insights for the development and application of new tools and methods to increase productivity and sustainability in almond growing. Three cultivars (Lauranne® Avijour, Guara Tuono, and Filippo Cea) were evaluated in Gravina in Puglia (BA) over a two-year period. Canopy growth parameters, such as canopy volume and trunk cross-sectional area, and architectural traits, like branching density, branching angle, number and length of subterminal shoots, and number of brachyblasts, were measured through qualitative and quantitative measurements. Results revealed significant differences in tree height, canopy thickness, width, volume, and vigor among the cultivars. Architectural traits, including branch parameters, brachyblast parameters, and subterminal shoots, varied among the cultivars. Lauranne displayed a more compact well-distributed canopy and exhibited the lowest vigor. Filippo Cea showed the highest vigor and the greatest canopy volume. Tuono had a higher number of buds and bud density. The best ideotype for SHD orchards is a smaller tree, with high branching density and smaller trunk diameters, i.e. the vigor. Cv. Lauranne seemed to be the best cultivar, mostly with the lowest tree vigor of all the cultivars involved. These findings provide valuable insights for almond growers and breeders seeking to optimize orchard design and management for enhanced SHD orchards productivity and sustainability. Future research will explore the relationship between canopy architecture and yield parameters, considering different scion/rootstock combinations in different environmental conditions.

Reduced Root Volume at Establishment, Canopy Growth and Fruit Production in ‘Lapins’/‘Colt’ and ‘Regina’/‘Gisela 12’ Sweet Cherry Trees

The success of establishing fruit orchards has traditionally been attributed to the vigor of the nursery plant used. This study aimed to evaluate the post-transplant survival, canopy growth and fruit productivity of two sweet cherry (Prunus avium L.) cultivars (‘Lapins’/‘Colt’ and ‘Regina’/‘Gisela 12’) with different radicular basal volumes of 100%, 50% and 25% and nursery plant types: (i) bare root (BR) or (ii) bagged (B). The initial stem diameter of the plants ranged from 12 to 19 mm, and their height ranged from 1.4 to 1.8 m. Plants grafted onto ‘Colt’ rootstock exhibited twice the initial root volume compared to those grafted onto ‘Gisela 12’. Evaluations were carried out in three commercial orchards during three seasons in the Central Valley of Chile. The results indicated that root volume and nursery type did not affect plant survival and productivity. For ‘Regina’/‘Gisela 12’, only the bag treatment resulted in less trunk cross-sectional area (TCSA) and shoot length, and for ‘Lapins’/‘Colt’, the BR25 treatment showed a lower initial TCSA than other treatments, although without a negative effect on yield. Hence, the presumption about the influence of root volume and plant type on the successful establishment of a sweet cherry on ‘Colt’ and ‘Gisela 12’ rootstock can be discarded. The survival, growth and precocity of the orchard depend more on post-planting conditions and water management than on the number or type of nursery plant roots. It is important to prioritize proper post-planting care and water management for optimal orchard health.

Localised and tree total crop loads influence trunk growth, return fruit set, yield, and fruit quality in apples

Localised fruit thinning strategies must be investigated to improve precision crop load management in narrow-canopy, multileader apple trees. This study aimed to determine the effects of within-leader and tree total crop load on leaders’ and trunk’s growth, fruit set, yield, and fruit quality in ‘Ruby Matilda’ apples (marketed as Pink Lady®) over three years. Different crop loads were imposed on two leaders (primary and secondary) of bi-axis trees. Leader and trunk relative growth rate, return fruit set, yield, and fruit quality parameters at harvest were measured. High within-leader crop loads led to a significant increase in yield and reductions in trunk growth, return fruit set, and deterioration of fruit quality parameters except for flesh firmness and starch index. Similar trends were observed in whole-tree relationships. High crop load in secondary leaders had moderate negative effects on trunk growth, yield, and fruit mass of primary leaders; it only marginally affected their return fruit set and had no significant effect (p > 0.05) on their fruit quality. A crop load of 6.8 fruit no. cm−2 of leader cross-sectional area was estimated to achieve a relatively consistent return fruit set within the same leader. At a whole-tree level, a similar crop load (6.9 fruit no. cm−2 of trunk cross-sectional area) produced a consistent return fruit set despite its higher variability. These crop loads produced high yields (120 and 111 t ha−1, respectively) and good quality fruit. Using individual leaders as management units is recommended to simplify operations and reduce variability.

Morphological Evaluation of Pear cvs. Santa Maria, Williams, and Deveci Grafted onto Clonal and Seedling Rootstocks

This research was conducted to determine the effects of quince clonal rootstocks [Quince BA29 (BA29) and Quince A (QA)], pear clonal rootstocks [FOX9, FOX11, OHxF333, OHxF87 and FAROLD40] and European pear seedling rootstocks on the morphological characteristics of 'Santa Maria', 'Williams', and 'Deveci' pear cultivars in Bafra (Samsun) ecological conditions in the research years of 2021 and 2022. Morphological characteristics, such as rootstock diameter (mm), trunk diameter (mm), trunk cross-sectional area (cm2), tree height (cm), crown dimensions (width, length, height and volume), leaf stalk length (cm), leaf stalk thickness (mm), leaf dimensions (width, length, area), annual shoot length (cm), node numbers and internode length (cm) were examined in the study. Results of the study revealed significant variation in the case of research years on most morphological attributes; generally, the values were higher in the research year 2022 than in 2021. It has been determined that the effect of rootstocks on all the morphological characteristics was significant except for leaf stalk thickness. The highest morphological values were obtained from OHxF333, FOX11, and FAROLD40 compared to the other rootstocks, and the lowest values were recorded in FOX9, OHxF87, and seedling rootstocks, respectively. Considering the cultivars' effect on the evaluated morphological traits, the highest leaf characteristics, and internode length in the annual shoots were acquired from the 'Santa Maria' cultivar, but all other attributes were higher in the 'Deveci' cultivar. The ' Williams ' cultivar recorded almost all the lowest morphological values. The highest trunk cross-sectional area was determined in the 'Deveci'/OHxF333 (38.63 cm2) and the lowest in the 'Williams'/FOX9 (4.95 cm2). The longest annual shoots were determined in the 'Deveci'/FOX11 (43.05 cm) and the shortest in the 'Williams'/Seedling (16.11 cm). The highest leaf area was observed from the 'Santa Maria'/BA29 (21.11 cm2) and 'Santa Maria'/FOX11 (20.95 cm2) combinations. According to the results of the research, it was determined that OHxF333 rootstock among the evaluated rootstocks performed morphologically better than the others. FOX9 and OHxF87 pear clone rootstocks showed very poor performance compared to other rootstocks.

Physiological and Growth Responses of W. Murcott Tangor Grafted on Four Rootstocks under Water Restriction

Citrus orchards in semi-arid regions are increasingly exposed to drought conditions due to climate change. This study compared the physiological and growth responses of ‘W. Murcott’ tangor (WM) grafted onto Citrus macrophylla (M), Swingle citrumelo (SC), C-35 citrange (C35), or bitter citrandarin (C22) rootstock subjected to two irrigation treatments: daily irrigation to replace 100% of the water lost daily by evapotranspiration (ET; control treatment) or daily irrigation to replace 75% of the water lost daily by ET (water deficit treatment). For trees in each treatment, leaf gas exchange, relative chlorophyll content, chlorophyll fluorescence, midday stem water potential, trunk cross-sectional area, and shoot length were measured 46 days after treatments were initiated. The results showed that WM on SC or C22 rootstock exhibited isohydric behavior, where decreased stomatal conductance limited transpiration in the water deficit treatment. WM on M rootstock exhibited an anisohydric response in the water deficit treatment, where there was no stomatal control of water loss by transpiration. Among the rootstocks tested for WM, the most tolerant to soil water deficit was SC, whereas trees on M rootstock were the most negatively affected by soil water deficit.

Phosphorus Fertilization Can Improve Young Almond Tree Growth in Multiple Replant Settings

Young almond (Prunus amygdalus) orchards replanted where old orchards of stone fruits (Prunus sp.) have been removed are subject to physical, chemical, and biotic stressors. Among biotic challenges, for example, is almond/stone fruit replant disease (ARD; formally known as Prunus replant disease), which specifically suppresses the growth and yields of successive almond and other stone fruit plantings and is caused, in part, by a soil microbial complex. During four orchard trials representing different almond replant practices and scenarios in the San Joaquin Valley in California, we examined the impacts of phosphorus (P) fertilization on the growth of replanted almond. During all trials, P was applied to tree root zones just after replanting, and the impact was assessed according to trunk cross-sectional area (TCSA) growth for 2 years. Expt. 1 was performed where a previous almond orchard was cleared using whole orchard recycling (i.e., the old orchard was “chipped” and then turned into the soil). The land was replanted without preplant soil fumigation. We tested separate fertilizer treatments based on various P, nitrogen, micronutrient, and “complete” formulations. Expt. 2 was also performed where an old almond orchard was recycled, but the soil was preplant-fumigated before replanting. Here, we tested only P fertilization. Expts. 3 and 4 were conducted where an old peach (Prunus persica) orchard was removed. Here, P and nitrogen fertilizer treatments were tested among additional factors, including preplant soil fumigation (Expts. 3, 4) and whole orchard recycling chips (Expt. 4). During all four trials, P fertilization (P at 2.2 to 2.6 oz/tree within a few weeks after planting) significantly increased TCSA growth. The growth benefit was nuanced, however, by almond cultivar, date of replanting, rootstock, and other site-specific factors. Although P fertilization did not match the benefit of preplant soil fumigation for the management of ARD, our data indicated that P fertilization can improve the growth of young almond orchards in diverse replant settings with or without preplant soil fumigation and should be considered by California almond producers as a general best management practice.

Foliar urea applications to apple trees increase yeast assimilable nitrogen, amino acids, and flavor volatiles in fruit and hard cider

Volatile compounds are a crucial component of hard apple (Malus ✕domestica Borkh.) cider aroma, flavor, and consequent marketability. Amino acids are used by Saccharomyces cerevisiae yeast in the production of volatiles and their precursors. This study hypothesized that foliar applications of nitrogen to apple trees would elevate the concentration of amino acids in the fruit, thus increasing the concentration of sensorially distinguishable aromatic volatiles in cider. In this experiment, urea foliar fertilizer was applied to ‘Ellis Bitter’ and ‘Harry Masters Jersey’ apple trees to create Control (0 applications), Low (3 weekly applications), and High (5 weekly applications) treatments. Total leaf nitrogen increased with the number of foliar urea applications, demonstrating plant uptake. The total fruit yield and fruit efficiency (total harvested fruit mass relative to trunk cross-sectional area) did not differ among treatments within the same cultivar. Similarly, fruit maturity, size, total phenolics, pH, and soluble solids concentration did not differ among treatments. Yeast assimilable nitrogen (YAN) and amino acids in the juice increased with the number of foliar urea applications, as did fermentation rates. Relative to the Control, the High treatment had 130% greater YAN in ‘Ellis Bitter’ and 145% in ‘Harry Masters Jersey’. Over 90% of the YAN in all juice samples was composed of primary amino nitrogen (PAN), and the majority of the PAN among all treatments was asparagine. Ester and fatty acid content in hard ciders increased with the number of urea applications; however, higher alcohols showed a mixed relationship with the number of applications in the cultivar ‘Ellis Bitter’. Aroma and flavor differences among treatments were discernible by triangle discrimination test panelists; however, the specific sensory differences were not easily identifiable with untrained panelists. This study demonstrated that late season foliar urea applications to apples trees can increase juice YAN and aromatic compounds in finished cider.

Rootstock vigor dictates the canopy light environment that regulates metabolite profile and internal fruit quality development in peach

Five rootstock cultivars of differing vigor: vigorous (‘Atlas™’ and ‘Bright's Hybrid® 5’), standard (‘Krymsk® 86’ and ‘Lovell’) and dwarfing (‘Krymsk® 1’) grafted with ‘Redhaven’ as the scion were studied for their impact on productivity, mid-canopy photosynthetic active radiation transmission (i.e., light availability) and internal fruit quality. Αverage yield (kg per tree) and fruit count increased significantly with increasing vigor (trunk cross sectional area, TCSA). Α detailed peach fruit quality analysis on fruit of equal maturity (based on the index of absorbance difference, IAD) coming from trees with equal crop load (no. of fruit cm−2 of TCSA) characterized the direct impact of rootstock vigor on peach internal quality [dry matter content (DMC) and soluble solids concentration (SSC)]. DMC and SSC increased significantly with decreasing vigor and increasing light availability, potentially due to reduced intra-tree shading and better light distribution within the canopy. Physiologically characterized peach fruit mesocarp was further analyzed by non-targeted metabolite profiling using gas chromatography mass spectrometry (GC-MS). Metabolite distribution was associated with rootstock vigor class, mid-canopy light availability and fruit quality characteristics. Fructose, glucose, sorbose, neochlorogenic and quinic acids, catechin and sorbitol were associated with high light environments and enhanced quality traits, while sucrose, butanoic and malic acids related to low light conditions and inferior fruit quality. These outcomes show that while rootstock genotype and vigor are influencing peach tree productivity and yield, their effect on manipulating the light environment within the canopy also plays a significant role in fruit quality development.

The overall effect of research years, rootstocks, and cultivars on the morphological attributes of pear trees

This research was conducted to determine the combined effect of 3 factors including rootstocks, cultivars, and research years on the morphological characteristics in Samsun/Türkiye ecological conditions in the research years of 2021 and 2022. Eight rootstocks consisting of quince BA29 (BA29), quince A (QA), FOX9, FOX11, OHxF333, OHxF87, FAROLD40, and European pear seedlings were used in the study, while the cultivars were 'Santa Maria', 'Williams', and 'Deveci'. The study results revealed the significance of the combined factors on all leaf characteristics of European pear. While rootstock diameter, scion diameter, tree length, and trunk cross-sectional area showed insignificant variations. It was determined that the canopy characteristics of ‘Williams' pear cultivar in combination with the FAROLD40 and OHxF333 in the research year 2022 were higher than other combinations, while the same combination was obtained with lower values in the case of other morphological characteristics. Generally, all the morphological attributes were obtained higher in the rootstocks and cultivars combination in the research year of 2022. In conclusion, the genetic capacity of rootstocks, cultivars, and variations of the climate situations in two consequent research years, resulted in variations in the morphological attributes of pear trees.

Fruitlet Thinning Reduces Biennial Bearing in Seven High-tannin Cider Apple Cultivars

Many European apple (Malus ×domestica Borkh.) cultivars used for making alcoholic cider have a highly biennial bearing habit. To determine target crop load recommendations, seven cider cultivars grown in a high-density orchard were hand-thinned to crop densities of 0, 3, 6, and 9 fruit/cm2 trunk cross-sectional area (TCSA) or left unthinned as a control for 3 consecutive years (2016–18). Treatments were imposed on the same trees for all 3 years. Greater year-to-year yield variability, as measured by the biennial bearing index (BBI), correlated negatively with cumulative yields both within and among cultivars. Greater crop density had a negative correlation with the amount of return bloom in all years, but reducing crop density had a negligible effect on return bloom in the “off” year. When trees were left unthinned in the high-crop “on” years there was little to no return bloom in the following year. Partial budget analysis found that manually reducing crop density would result in a positive net change in 3-year profitability for Dabinett, but not the other cultivars. Over 4 years, under conservative assumptions about fruit set, chemical thinning to 9 fruit/cm2 TCSA would likely result in increased cumulative profitability in all seven cultivars. Hand-thinning was projected to be less profitable than chemical thinning but would still result in increased net profitability over 4 years, for five of the seven cultivars. These findings highlight the horticultural and economic benefits of crop load management for cider apple orchards. Further, many high-tannin cider cultivars can sustain a higher crop density than what is recommended for fresh-market apple production and still have adequate return bloom and cumulative yields.

THE IMPACT OF THE PRUNING TIME ON THE BIOLOGICAL PROPERTIES OF CHERRY VARIETIES GRAFTED ON MAXMA 14

Pruning is a basic procedure in the sweet cherry trees cultivation, which significantly affects the yield and quality of the fruit. The objective of this study was to examine the influence of the pruning time on the biological properties of sweet cherry trees (Prunus avium L.). The orchard in which the research was carried out was established in the central area of the Republic of Moldova in the fall of 2012. The Kordia and Regina sweet cherries, grafted on MaxMa 14, whose crowns had a naturally improved reduced volume, were planted at a distance of 5 x 3 m. The maintenance and fruiting pruning of the sweet cherry trees were done during the dormant and vegetation phases as follows. The flowering and fruit ripening time, the trunk cross-sectional area (TCSA), the number of fruiting buds and the fruit weight and yield were studied. The results showed that the pruning time had had a significant impact on the yield. The data on the yield of the Kordia and Regina sweet cherry varieties grafted on MaxMa 14 are promising and prove that the pruning done in the first decade of September has a positive effect on the fruit yield.

Effect of Crop Load on Yield and Quality Parameters in Apple cv. Gala Redlum

The present study was conducted at the experimental field of the Division of Fruit Science, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir during the year 2021-2022. The primary objective of this study was to assess the impact of varying crop loads on the growth, yield, quality, and return bloom of Gala Redlum apples, with specific emphasis on trunk cross-sectional area (TCSA). The experimental design involved a Randomized Complete Block Design (RCBD) with three replications, utilizing 4-year-old Gala Redlum plants. The trees were subjected to manual thinning, resulting in crop loads of 4, 6, 8, 10 fruits per cm² of TCSA, with a non-thinned control group. Notably, the maximum fruit yield (18.52 kg/tree) was observed in the control group (no thinning), while the minimum yield (7.57 kg/tree) was recorded in the C2 group (4 fruits per cm² of TCSA), followed by C3 (11.03 kg/tree). Furthermore, the impact of different TCSA ranges on fruit yield was statistically significant. The maximum fruit yield (14.45 kg/tree) was observed in the S2 group (10-12 cm² TCSA), while the minimum yield (12.16 kg/tree) was noted in the S1 group (8-10 cm² TCSA). Yield efficiency, measured as yield per unit of TCSA, reached its highest (1.838 kg/cm²) in the control group and is lowest (0.766 kg/cm²) in the C2 group (4 fruits per cm² of TCSA). The results further revealed that the C2 group (4 fruits per cm² of TCSA) exhibited the maximum Total Soluble Solids (TSS) content (14.73 °Brix), total sugars (11.62%), and TSS: Acid ratio (61.45). Similarly, the C3 group (6 fruits per cm² of TCSA) demonstrated elevated TSS (14.20 °Brix), total sugars (10.99%), and TSS: Acid ratio (54.66). Additionally, the S2 group (10-12 cm² TCSA) recorded the highest TSS (13.75 °Brix), total sugars (10.51%), and TSS: Acid ratio (50.53). The combination of C2S2 and C3S2 treatments exhibited superior results, with the highest TSS (14.82 °Brix), total sugars (11.77%), and TSS: Acid ratio (62.64). Fruit firmness (8.81 kg/cm²) and fruit acidity (0.327%) were maximized in the C1S1 treatment combination.

Impact of Crop Load on Growth, Flowering and Fruiting in Apple cv. Gala Redlum

This study assesses the influence of varying crop loads on growth, return bloom and fruiting traits with a focus on trunk cross-sectional area (TCSA)in High-Density Apple Cultivar Gala Redlum, Study was conducted at the experimental field of the Division of Fruit Science, SKUAST-Kashmir, during 2021-2022.The experiment, organized in a randomized complete block design (RCBD) with three replications, utilized 4-year-old "Gala Redlum" plants. The trees were hand-thinned to 4, 6, 8, 10 fruits per cm2 of TCSA, with a control group undergoing no thinning. Results indicated that the highest values for annual shoot length (36.40 cm), return bloom (111.50 flower clusters/tree), fruit length (68.49 mm), fruit diameter (75.07 mm), and fruit weight (191.62 g) in the C2 treatment (4 fruits per cm2 of TCSA). Following closely, the C3 treatment (6 fruits per cm2 of TCSA) exhibited substantial values for the aforementioned parameters. Furthermore, the S2 treatment (10-12 cm2 TCSA) recorded maximum annual shoot length (30.63 cm), return bloom (64.13 flower clusters/tree), fruit length (61.74 mm), fruit diameter (69.18 mm), and fruit weight (168.16 g). Notably, the combined treatment C2xS2 yielded the highest return bloom (114.00 flower clusters/tree) and fruit characteristics (fruit length, diameter, and weight).

Determination of Target Crop Loads for Maximising Fruit Quality and Return Bloom in Several Apple Cultivars

In apple (Malus domestica), the level and timing of crop load have a major impact on the final fruit size and can also play a role in optimising internal fruit quality. Ideal crop loads vary with cultivar, but very few cultivars have recommended crop load targets that consider the effect of crop load on both return bloom and fruit quality. To address this issue, studies examining a range of crop loads and thinning times were undertaken on several apple cultivars. Return bloom and multiple fruit quality parameters were examined. The results of these studies demonstrate positive effects for early thinning, not only on fruit size but also on firmness and soluble solids content. Early-thinned fruit showed higher sugar levels than late-thinned fruit. Previously undemonstrated positive relationships between fruit sugar content and weight and between fruit firmness and weight in both ‘Fuji’ and ‘Delicious’, as well as between fruit sugar content and fruit firmness in ‘Delicious’, indicate that early thinning is a valuable tool in improving fruit quality. The current target crop load recommendations of 4–6 fruit cm−2 trunk cross-sectional area (TCSA) for ‘Fuji’ and 2–4 fruit cm−2 TCSA for ‘Delicious’ are confirmed by this study. New recommendations are proposed for the other cultivars in this study taking into account the impact of crop load on both fruit quality and return bloom. Both ‘Pink Lady’ and ‘Gala’ can support crop loads of up to eight fruit cm−2 TCSA without impacting return bloom, but fruit quality is compromised; hence, lower targets in the range of 4–6 fruit cm−2 TCSA are recommended. Large fruit size and good return bloom can be maintained in ‘Jonagold’ at crop loads of eight fruit cm−2 TCSA, while crop loads of four fruit cm−2 TCSA are suggested for ‘Braeburn’ to sustain regular bearing and good fruit size.