Research Orchard Research Articles

Comparison of Standard Calendar GA4+7 Plant Growth Regulator Programs to Applications Timed to Rainfall Events for Management of Scarf Skin, a Fruit Finish Disorder of Apple

Scarf skin is a fruit finish disorder of apple that leads to reduced grade quality and rejected crop loads. Although not established as a disorder specific to certain cultivars, the manifestation of the disorder is more apparent on red-skinned cultivars such as Gala and Stayman at harvest, where its whiteish cast is held in clear contrast with the redness of the mature fruit. The disorder afflicts fruit during the first 40 days after petal fall as the fruitlet is developing, although symptoms of the disorder may not be clearly visible until many months after. The exact causes of apple scarf skin are not well defined, although it is known that the presence of the disorder can be influenced by environment, fruit size, and some pesticides. Management currently relies on four applications of the plant hormones gibberellins A4 and A7 (GA4+7) during the first 40 days after bloom. Here, we describe our attempts to use a commercialized GA4+7 product (ProVide 10SG) starting at petal fall, with applications made after or before rainfall events, to ease rainfall's putative influence on scarf skin development. We compared our programs to the standard program over 4 years in research orchards and a commercial orchard but observed no consistent reduction in scarf skin severity or incidence of out-of-grade fruit, in part due to the year-to-year variability in the manifestation of scarf skin. Rainfall, at the thresholds defined, does not appear to be a sufficiently significant factor influencing scarf skin development such that a GA4+7 management program can be designed. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Conventional vs. nano-micronutrients as foliar fertilization for enhancing the quality and nutritional status of pomegranate fruits

Currently, nanotechnology is widely used in agriculture and horticulture. Nanofertilizers are essential for encouraging vegetative growth and flowering, as well as enhancing productivity and fruit quality. These nanoparticles are viewed as growth promoters as well. The current study was therefore carried out during the two successive seasons of 2021 and 2022 on 14-year-old trees grown in clay soil in a field experiment at the Pomology Department Research orchard, Faculty of Agriculture, Assiut University, Egypt. The effects of conventional vs. nano-micronutrients as foliar fertilizers on the fruit yield, quality, and mineral nutrition status of pomegranate trees were studied. The foliar application of all treatments on pomegranate trees remarkably increased yield and physical properties of fruits as well as improved the levels of total soluble solids percentage, anthocyanin pigment, flavonol, total phenols, antioxidant activity and nutrients status compared with the controls during the 2021 and 2022 seasons. The lowest fruit cracking percentages were obtained by the spraying of nano-micronutrients (4.33–5.70 %) compared with the other treatments and the control, which gave the highest percentages (10.45–11.43 %). The highest increments in yield, physical properties of fruits and levels of total soluble solids percentage, anthocyanin pigment, flavonol, total phenols, and antioxidant activity were noticed by the spraying of nano-micronutrients especially at 1000 and/or 1500 µg mL−1. It could be concluded that the use of nanofoliar fertilization in pomegranate cultivation may improve the yield, quality, and nutritional status of pomegranate fruits.

Integration of Chitosan and Biopesticides to Suppress Pre-Harvest Diseases of Apple

The natural product chitosan has been shown to reduce plant disease severity and enhance the efficacy of microbial biocontrol agents in several crops. However, little is known about the potential synergisms between chitosan and biopesticides and best use practices in apple production. The objectives of this study were to evaluate the effect of pre-harvest applications of chitosan alone and in combination with a commercial biopesticide to suppress fungal diseases of apple and to investigate the potential for chitosan to reduce the quantity of overwintering Venturia inaequalis spores in orchard leaf litter. Chitosan products, Tidal Grow and ARMOUR-Zen 15, and a commercial biopesticide, Serenade ASO, were tested in a research orchard in Pennsylvania and commercial orchards in New Hampshire. Chitosan applications reduced apple scab incidence and severity by up to 55% on fruit compared to the water control. Chitosan also reduced sooty blotch, flyspeck, and rust incidence on fruit. Furthermore, a chitosan + biopesticide treatment overlayed onto a grower standard spray program reduced diseases more effectively than the grower standard alone. However, this efficacy was dependent on the cultivar and pathogen. Chitosan did not reduce overwintering V. inaequalis ascospores. This research provides evidence that pre-harvest chitosan applications have the potential for disease management in apple production.

Evaluation of reflective groundcovers for pest and fruit quality management in commercial pear orchards

AbstractReflective groundcovers can improve crop yield and quality and deter pests by increasing light penetration into plant canopies. In pear (Pyrus communis L.) orchards, this could increase profitability and reduce reliance on insecticides to manage pear psylla (Cacopsylla pyricola [Foerster]). Two types of reflective groundcovers, metallized polyethylene film (metallized film) and white geotextile fabric (reflective fabric), are known to increase pear yield and quality, and metallized film was recently reported to suppress pear psylla. Here, we tested reflective fabric for pear psylla suppression at a research orchard in 2019, then we partnered with five pear orchard managers to test metallized film and reflective fabric for pear psylla suppression at five conventional commercial orchards in 2020 and one organic commercial orchard in 2021. There was evidence of pear psylla suppression by both metallized film and reflective fabric, but effects varied among reflective materials, pear psylla life stages, season and year of study. Reflective groundcovers did not affect fruit size, weight, sunburn or pest mite abundance, and they were compatible with pear psylla biocontrol. Low perceived benefit relative to cost was a barrier to continued trialling and adoption. Whereas orchardists in our study used reflective groundcovers in addition to normal pesticide regimes, previous research studies suggest that reflective groundcovers can profitably replace some insecticides. Future studies are needed to test the outcomes of replacing pesticides with reflective groundcovers in commercial orchards and understand under what circumstances they improve pear quality and yield.

Rapid Assessment of Architectural Traits in Pear Rootstock Breeding Program Using Remote Sensing Techniques

Over the decades in the US, the introduction of rootstocks with precocity, stress tolerance, and dwarfing has increased significantly to improve the advancement in modern orchard systems for high production of tree fruits. In pear, it is difficult to establish modern high-density orchard systems due to the lack of appropriate vigor-controlling rootstocks. The measurement of traits using unmanned aerial vehicle (UAV) sensing techniques can help in identifying rootstocks suitable for higher-density plantings. The overall goal of this study is to optimize UAV flight parameters (sensor angles and direction) and preprocessing approaches to identify ideal flying parameters for data extraction and achieving maximum accuracy. In this study, five UAV missions were conducted to acquire high-resolution RGB imagery at different sensor inclination angles (90°, 65°, and 45°) and directions (forward and backward) from the pear rootstock breeding plot located at a research orchard belonging to the Washington State University (WSU) Tree Fruit Research and Extension Center in Wenatchee, WA, USA. The study evaluated the tree height and canopy volume extracted from four different integrated datasets and validated the accuracy with the ground reference data (n = 504). The results indicated that the 3D point cloud precisely measured the traits (0.89 < r < 0.92) compared to 2D datasets (0.51 < r < 0.75), especially with 95th percentile height measure. The integration of data acquired at different angles could be used to estimate the tree height and canopy volume. The integration of sensor angles during UAV flight is therefore critical for improving the accuracy of extracting architecture to account for varying tree characteristics and orchard settings and may be useful to further precision orchard management.

ESTABLISHMENT OF STRATEGY FOR MANGO HOPPER IDIOSCOPUS CLYPEALIS(LETHIERRY) MANAGEMENT AND IMPACT OF WEATHER FACTORS ON ITS POPULATION IN SOUTH PUNJAB PAKISTAN

Mango is an important, exportable fruit crop of Pakistan. Pakistan is occupying 6th position on the basis of mango production in almost 90 mango producing countries of the world. The mango hopper Idioscopusclypealis is a most destructive insect pest of mangoes in Pakistan. This pest may cause the economic loss to the mangoes due to due to its abundance and high population in dense traditionally managed mango orchards. Keeping in view the importance of the pest, a study was designed with an objective to determine comparative efficacy of four different insecticidal spray modules for effective control of mango hopper on cultivar SufaidChaunsa in the research orchards of Mango Research Institute, Multan during 2019-2021. Another objective was to determine the population dynamics of mango hopper and the effect of weather factors on the population of mango hopper. The infestation of the pest was examined by observing nymphs and adults in a single panicle/inflorescence (10-inch long) from each cardinal directions of the selected trees visually counted during the flowering season on weekly basis. In module 1, Thiamethoxam (Actara 25 WG) was sprayed after the fruit harvest. In module 2, the insecticide Thiamethoxam (Actara 25WG) was sprayed after the fruit harvest, followed by second spray of Clothianidin (Trunk 20SC) only on tree trunks in the month of December. In module 3, first spray of thiamethoxam was done after fruit harvest, second spray of Clothianidin (Trunk 20SC) only on tree trunks in the month of December and a subsequent third spray of Spinetoram (Delegate 25 WG) was done on mango trees before flowering season in the month of January. The population of mango hopper was significantly lowest in module 3 and higher population of hopper was recorded in control. Population dynamics studies revealed that mango hopper population reached at its peak in 2nd week of April during 2020 and 3rd week of March in 2021. The population of mango hopper was maximum during mango flowering period, while in the later months the population of mango hopper declined. The effect of weather factors on population abundance of mango hopper revealed that significantly positive correlation and regression was observed with relative humidity and wind while negative correlation was observed with increased temperature and rainfall.

Effect of Humic and Salicylic Acids Foliar Application on Vegetative Growth and Fruit Quality of Olive (c.v Sorani and Khadrawi)

This study was carried out on 15 years old trees of two Syrian olives (Olea europaea L.) cultivars Sorani and Khadrawi during 2020-2021 growing season at research orchard, of Horticulture department / College of Agricultural Engineering sciences, University of Sulaimani, Iraqi Kurdistan region. Humic and salicylic acids foliar application with three levels (0, 2000 and 4000 ppm) and (0, 750 and 1500 ppm) were applied respectively (before and after full bloom as well as at fruit set). The parameters annual shoot length, fruit set percentage, fruit weight, fruit volume, oil content in fruit and leaf (nitrogen, phosphorus and potassium) content were studied, and the results showed that cultivar had significant effects on all studied parameters except (fruit weight and fruit volume). Maximum concentration of humic acid (4000ppm) recorded maximum values in all parameters compared to the other concentrations, and also had significant effects on all parameters. Except (fruit volume) all parameters be affected significantly by salicylic acid application.

Integrated Pest Management Programs for Pear Psylla, Cacopsylla pyricola (Förster) (Hemiptera: Psyllidae), Using Kaolin Clay and Reflective Plastic Mulch.

Pear psylla, Cacopsylla pyricola (Förster) (Hemiptera: Psyllidae), is the most economically important pest of pears grown in Washington State. Standard conventional management programs involve season-long broad-spectrum insecticide sprays. Although the industry uses some tools that are not disruptive to biological control, such as kaolin clay and selective insecticides, they are additions to broad-spectrum insecticides instead of replacements. Conventional sprays suppress pear psylla through the spring and early summer; however, disruption of biological control leads to pear psylla outbreaks near harvest. In 2018 and 2019, we tested two season-long programs that used only selective approaches. The programs began with either kaolin clay or reflective plastic mulch and were followed by identical spray programs using only selective insecticides. Programs were compared with an industry standard conventional program that used numerous broad-spectrum insecticides throughout the season, and a check program with no insecticides for pear psylla. Experiments were conducted using replicated 40-tree plots in a research orchard near Wenatchee, WA with high pear psylla pressure. In both years, selective programs had similar pear psylla densities to the industry standard program and all had lower pear psylla densities and fruit injury than the check. Both selective programs had lower fruit injury than the industry standard in the first year, and similar injury to the industry standard in the second year. Our results suggest kaolin clay and reflective mulch can effectively suppress pear psylla populations and injury in the early season and support season-long selective management programs without the use of broad-spectrum insecticides.

Incorporating diapause to predict the interannual dynamics of an important agricultural pest

AbstractWe develop a new population‐scale model incorporating diapause induction and termination that allows multi‐year predictions of pest dynamics. In addition to predicting phenology and voltinism, the model also allows us to study the degree of overlapping among the life‐stages across time; a quantity not generally predicted by previous models yet a key determinant of how frequently management must be done to maintain control. The model is a physiological, stage‐structured population model that includes temperature‐dependent vital rates, diapause processes, and plasticity in development. The model is statistically fitted with a 33‐year long weekly term time series of Cydia pomonella adults captured in pheromone‐baited traps from a research orchard in southern Pennsylvania. The multiannual model allows investigation of both within season control strategies, as well as the likely consequences of climate change for this important agricultural pest. The model predicts that warming temperatures will cause earlier spring emergence, additional generations, and increased overall abundance. Most importantly, by calculating the circular variance, we find that warmer temperatures are associated with an increase in overlap among life‐stages especially at the beginning of the growing season. Our findings highlight the importance of modeling diapause to fully understand C. pomonella lifecycle and to better inform management for effectively controlling this pest in a warmer future.

Factors Affecting the Infection of Sweet Cherry (Prunus avium) Fruit by Podosphaera cerasi.

Powdery mildew caused by Podosphaera cerasi is the most important fungal disease of sweet cherries in the Pacific Northwest of the United States. In this study, several factors related to disease epidemiology were evaluated. The experiments were conducted to investigate flower susceptibility to P. cerasi infection by in planta and invitro inoculation. The susceptibility of fruit at various developmental stages was investigated using defined concentrations of P. cerasi conidia. Furthermore, the threshold of conidial concentration required for fruit infection was determined. The pathogen activity during full bloom was limited and not related to fruit disease incidence and severity at harvest. Foliar infections always preceded fruit infections by an average of 42 days during the 3 years of the study. The onset of fruit infection followed, on average, 66 days after full bloom and appeared simultaneously on all susceptible cherry cultivars in the research orchard. Disease symptoms were only observed on fruit in Biologische Bundesanstalt, Bundessortenamt, and Chemical Industry scale 8 (maturity) in all cultivars examined. During this stage, a concentration of 500 conidia/ml was sufficient to cause fruit infection at harvest. Interaction between the inoculation dates and conidial concentration revealed a dependency of disease development on the host stage at the time of inoculation; the younger the fruit, the more conidia are needed to cause disease at harvest. Molecular studies showed a rapid increase in conidia viability at the transition from asymptomatic to the symptomatic disease of fruit. No evidence of ontogenic resistance of fruit to powdery mildew infection was observed.

Bagging Apple Fruit for Codling Moth Control in Western Montana

Codling moth (Cydia pomonella) is a major insect pest of apple (Malus domestica). If unmanaged, then codling moth can infest nearly all apples in an orchard, where the flesh-tunneling larva leave frass-laden tracks in the fruit. Insecticide-based management requires accurate application timing (typically based on adult moth and/or degree-day monitoring) and multiple spray applications. Both the season-long commitment to codling moth monitoring and management and limited familiarity with insecticides, application tools, and proper application procedures can prevent a small-scale or backyard grower from effectively limiting fruit damage. In addition, an increasing segment of growers is interested in nonchemical alternatives. Bagging fruitlets early in the season could be a simple and effective method of codling moth management for this subset of growers. At our research orchard in Corvallis, MT, we tested a method combining fruit thinning and bagging using plastic bags the first season and nylon bags the second season. Plastic bags reduced the incidence of codling moth damage to fruit from 34% to 10%, but european earwig (Forficula auricularia) frass, which was found in more than 50% of plastic-bagged apples, made harvesting the fruit unappealing. We tested nylon fruit bags during the second year of the study. These bags did not significantly reduce the incidence of codling moth. Both the soluble solids content and titratable acidity were higher in unbagged fruit during the second year of the study, whereas color measurements indicated bagged fruit were greener on the shaded side of the fruit. Failure of the nylon bags may have been attributable to eggs laid before bagging, eggs laid or larva burrowing through bagging, or improper bag application methods. Further research could assess whole-tree bags, the addition of rubber bands or twist ties when applying nylon bags, pretreatment of fruit with horticulture oil, and/or dipping nylon bags in kaolin clay before application; however, these steps add time and increase costs, which may discourage the small-scale fruit grower. Overall, results indicate that fruit bagging holds promise for codling moth management; however, further work is needed to optimize the methodology.

First Report of Citrus tristeza virus Infecting Citrus Trees in Georgia, USA.

Citrus tristeza virus (CTV) [genus Closterovirus; family Closteroviridae] is one of the most important, economically devastating viruses of citrus worldwide. On citrus trees grafted onto sour orange rootstock, typical CTV symptoms include dieback and defoliation, stunting, curling and chlorotic leaves, stem-pitting, and pinholes below the bud union on the inner face of the bark (Moreno et al. 2008). This single-stranded, positive-sense RNA virus is most efficiently transmitted by the brown citrus aphid (Toxoptera citricida), but it can also be transmitted by other aphid species and through grafting of infected plant material onto healthy plants (Moreno et al 2008; Herron et al. 2006). In Fall 2020, leaf material for virus testing was collected from 13 navel orange trees (Citrus × sinensis) grafted onto Poncirus trifoliata rootstocks (including 'Flying Dragon') located in a citrus research orchard in Tifton, GA. Trees ranged in age from 2 to 10 years, with the younger trees having been grafted from cuttings taken from the older trees. The oldest of these trees was derived from cuttings taken in 2009 from an orange tree growing locally in a residential yard in Tifton; this parent tree was more than 15 years old when these cuttings were obtained and was no longer available for sampling as of 2020. Symptoms or other visible signs of disease had not been noted on any of the tested trees, and trees were chosen for testing prior to the further dissemination of this plant material. The presence of CTV was verified via molecular and serological testing. CTV infection was initially confirmed in 8 of 13 tested samples using the ImmunoStrip® for CTV assay (Agdia® Inc., Elkhart, IN, cat no: ISK 78900/0025) according to the manufacturer's instructions. RNA was extracted from leaf material collected from the 13 sampled trees using the RNeasy Plant Mini Kit (Qiagen, Valencia, CA). Following cDNA synthesis, samples were tested for the presence of CTV by reverse-transcription PCR using primer pair AR18F (5'-ATGTCAGGCAGCTTGGGAAATT-3') and AR18R (5'-TTCGTGTCTAAGTCRCGCTAAACA-3') which produces a 511 bp amplicon (Roy et al., 2005). PCR reactions confirmed the presence of CTV, with the same eight samples that had previously tested positive via Immunostrip® producing PCR fragments of the expected size. Amplified products from two of these samples were then sequenced using Sanger sequencing (Retrogen Inc, San Diego, CA, USA) and subjected to BLAST analysis (https://blast.ncbi.nlm.nih.gov/Blast.cgi) for further identification. Sequence analysis revealed that the obtained partial sequences (MW540805) from the p18 gene of both isolates were 100% identical to one another and shared 100% identity to corresponding sequences from CTV strain N4 (MK779711.1). To the best of our knowledge, this is the first report of CTV infecting citrus plants in Georgia. CTV could pose an imminent threat to the emerging citrus industry in Georgia if it were to become established in commercial citrus plantings either via the dissemination of infected plant material or via vector transfer of the virus under field conditions. While the brown citrus aphid is not known to be widespread in Georgia at this time, other CTV vectors are prevalent including the cotton aphid (Aphis gossypii) and the black citrus aphid (T. aurantia). Georgia citrus growers and plant propagators should be aware of this virus and take appropriate control measures to prevent the spread of this viral diseas.

Enhancement of freezing tolerance of olive leaves by foliar application of methyl jasmonate and 24–epibrassinolide through changes in some metabolites and antioxidant activity

The olive production is limited by the important factor of winter freezing damage. The purpose of this research was to investigate the probable role of exogenously applied methyl jasmonate (MeJA; 0.02, 0.1, and 0.2 mM) and 24–epibrassinolide (EBR; 0.2, 0.4, and 0.6 μM) to alleviate the adverse effect of freezing stress in olive (Olea europaea L. cv. Koronieki) leaves, which was conducted in a research orchard. Furthermore, some physiological and biochemical changes were studied in olive leaves at six sampling dates, and their relationship with freezing tolerance (expressed as LT50) were investigated. The results indicated that the olives freezing tolerance, soluble carbohydrates, proline, total soluble proteins, antioxidant enzymes, DPPH radical scavenging capacity, as well as total phenolic content were significantly increased using the foliar application of MeJA and EBR. The highest and lowest freezing tolerance in EBR 0.6 μM and control olives was as much as –8.22 °C and–6.87 °C, respectively. The LT50 profile had a significant negative correlation with accumulation of some compounds such as leaf soluble carbohydrates, total soluble protein, total phenolic content, DPPH scavenging capacity, as well as activating the catalase enzyme. Moreover, EBR 0.6 μM and control treatments respectively had the highest and lowest ratio between unsaturated fatty acids and saturated fatty acids (UFA/SFA ratio), especially in January. It can be concluded that the freezing tolerance of olive leaves can be increasing by the foliar application of MeJA and EBR treatments, which can be utilized as a preventive instrument to decrease freezing damage.

Examining Spatial Distribution and Spread of Fire Blight in Apple Orchards: Two Case Studies

Fire blight, caused by the bacteria Erwinia amylovora, is an incredibly destructive disease of apples, capable of spreading rapidly through an orchard block. The pathogen is endemic to many apple production regions worldwide, but it is often introduced into newly planted sites on infested host material, while locally it is typically vectored by wind-driven rain, hail, and insects. Here we presented two case studies of orchard blocks infected with fire blight at the Cornell AgriTech Research orchards in which CRISPR pattern characterization was used to identify strains present in the blocks and spatial analyses were used to describe the distribution and spread of the disease over the course of 2 years. Results indicated two very different sources of introduction (a nearby block or planting material) and patterns of spread (from a corner of the field or from focal points within the block). Describing the distribution and spread of fire blight within and between orchard blocks has the potential to improve our understanding of the disease movement, inform appropriate management recommendations, and facilitate traceback efforts.

Save Our Species: A Blueprint for Restoring Butternut (Juglans cinerea) across Eastern North America

Abstract Butternut is a relatively uncommon hardwood tree native to eastern North America. The species’ abundance has declined over the past 50 years, primarily because of an invasive pathogen (Ophiognomonia clavigignenti-juglandacearum [Oc-j]) and loss of suitable habitat for regeneration. Although genetic diversity of butternut is highest along the southern range edge, genetic diversity rangewide is fairly high, except in small and isolated populations. Although there is little evidence for even moderate resistance in native butternut, hybrids with Japanese walnut, a closely related species, display enough tolerance to infection to persist on the landscape and bear abundant nut crops year after year. Cryostorage of native embryogenic axes has yielded promising initial results as a strategy for gene conservation, but additional action is needed to conserve the remaining native gene pool. We describe a strategy for canker-resistance breeding in butternut using naturally occurring hybrids, hybrids in research orchards, and sources of native trees from as many regions as possible. Forest managers are encouraged to find surviving trees and collect seed for planting in suitable habitat to develop actionable knowledge that will enable the restoration of butternut with enough resistance to be self-sustaining on the landscape.

Management of Pear Psylla (Hemiptera: Psyllidae) Using Reflective Plastic Mulch.

Pear psylla, Cacopsylla pyricola (Förster), has remained the most challenging pest of commercial pears in Washington and Oregon, the top producers of pears in the United States. The lack of effective integrated pest management tactics for this pest has been a major barrier to effective management. In this study, we examined the potential for reflective plastic mulch affixed beneath pear trees to suppress pear psylla. In 2017 and 2018, single pear tree (cv. Bartlett) plots of reflective plastic mulch, black plastic mulch, and no mulch (check) were established in a research orchard to compare their effects on pear psylla. Arthropods were sampled every 7-14 d from March through late summer. In both years, reflective mulch plots had significantly fewer pear psylla adults, eggs, and nymphs of the first generation compared with black plastic and check plots. However, later generations of psylla were not suppressed by reflective mulch. Semi-field tests were conducted in 2019 and 2020 using uniformly pruned potted pear trees on either reflective plastic mulch or grass to determine whether summerform adults were tolerant to reflected light from mulch, or if shading from vegetative growth negated the effect of the mulch. In both years, significantly fewer summerform adults and eggs were found in reflective mulch plots, suggesting that shading, rather than summerform tolerance, reduced effects from reflective mulch in the summer. This study demonstrates the potential for reflective mulch to suppress pear psylla and justifies future examination as part of a season-long management program.

Apple phenology occurs earlier across South Korea with higher temperatures and increased precipitation.

This study examined relationships between temperature, precipitation, geo-topography, and the spring phenology of Fuji and Hongro apple cultivars along spatial gradients across South Korea. Phenology data was gathered from 2011 to 2014 in 42 uniformly managed research orchards which span a range in climate, latitude, and elevation. We used linear models and spatially explicit forecasts to study apple phenology under climate change scenarios. Given dry winters and complex terrain in South Korea, we hypothesized that, in addition to temperature, precipitation and geo-topographic factors influence apple phenology. We also expected responses to climate variation to be similar between (spatial) and within (temporal) orchards, given the controlled conditions and the use of apple clones in this study. With other factors held constant, phenological sensitivity ranged from - 3.2 to - 3.4days°C-1 for air temperature and - 0.5 to - 0.6dayscm-1 for March precipitation in a combined model. When modeled without temperature, phenology changed by up to 10days over the full range in March precipitation. Spring temperatures and precipitation in March had very little cross-correlation (r< 0.05), suggesting these patterns are independent; however, in a combined model including temperature, predicted changes in precipitation over the next 80years have only a small impact on future apple phenology. Combining the best models with climate forecasts for South Korea, spring phenology continues to occur earlier over the next 80years, mostly due to warming temperatures but with strong variation between regions. This suggests regionally specific climate change adaptation strategies are needed for future apple production in South Korea.

Foliar application of potassium to improve the freezing tolerance of olive leaves by increasing some osmolite compounds and antioxidant activity

Freezing damage is an important factor that limits olive production. The main aim of the present research was to investigate the possible impacts of the foliar application of potassium sulphate (K; K2SO4; 0.0, 0.5, 1.0, and 2.0 %) fertilization on the freezing tolerance (FT). Further, this research evaluated some physiological and biochemical changes of ‘Rashid’ olive (Olea europaea L.) at six sampling dates; these included November, December, January, February, April, and July. For this purpose, K was sprayed three times at 1-week intervals starting on 22 August 2016, on 16-year-old olives that had been located in a research orchard at Isfahan University of Technology (Iran), based on randomized complete block design. The results revealed that the effect of K sprays on the olives FT was significant at six stages of sampling. This was such that the highest (LT50 = −11.17 °C) and lowest FT (LT50 = −6.98 °C) was recorded in 2.0 % K-treated and control untreated olives during January, respectively. In addition, K application, particularly at 2.0 %, led to high increases of carbohydrate, proline, protein and total phenol concentration, antioxidant enzyme activity and DPPH (1, 1-diphenyl-2-picrylhydrazyl) scavenging capacity, as well as the ratio between unsaturated fatty acids and saturated fatty acids (UFA/SFA). It could be concluded that the foliar application of K could contribute to enhancing the olives FT by changing UFA/SFA ratio, in addition to the changes in other metabolites, like the accumulation of soluble carbohydrate, proline, protein, total phenol content and activation of the antioxidant system.

Effect of gamma irradiation treatment at phytosanitary dose level on physiological and consumer traits of Indian ber. Part 1. Cultivar ‘Umran’

We, study the effect of γ-irradiation on postharvest physiology, decay loss, consumer testing parameters and chilling injury index of Indian ber cv. ‘Umran’. Fresh fruits of original cultivar ‘Umran’ were purchased from research orchard. Fruits irradiated at 0 (as control), 0.4 or 1.0 kGy doses, and then cold stored (10 °C and 95% RH) for 35 d. Weight loss (WL), respiration rate, ethylene production, ripening index, firmness, chilling injury index and consumer testing parameters were tested during storage at 7 d interval. The results indicated that the application of irradiation successfully extended the postharvest marketable life of jujube fruit without any risk of disorder development. In comparison with control, irradiated fruit with 1.0 kGy, showed a significant reduction (P < 0.05) in WL, firmness, decay and ripening index. Moreover, irradiation caused a significant effect on consumer liking traits and chilling injury. In addition, irradiation also reduces the respiration and ethylene production rate however, ethylene peaks was delayed by 7 days at 1.0 kGy dose. Overall, irradiation dose at 1.0 kGy recommended as a postharvest treatment for a longer shelf life of Indian jujube.

Productivity and nutritional and nutraceutical value of strawberry fruits (Fragaria x ananassa Duch.) cultivated under irrigation with treated wastewaters.

Agriculture represents a productive sector typically characterized by a high water demand, whereas freshwater (FW) availability is a problem of increasing concern in the world and FW resources are becoming insufficient for sustaining agricultural irrigation. The reuse of treated wastewaters (TWWs) for crop irrigation could be an efficient tool for reducing water shortage. Hence, the present study evaluated the food quality of Fragaria x ananassa (cultivar Camarosa) fruits irrigated with four types of treated wastewaters (TWWs). Strawberries were analysed for yield, sucrose, fructose, glucose, total soluble polyphenols (TSP), total monomeric anthocyanins (TMA), and antiradical and antioxidant capacity. In addition, a targeted quantification of the most representative phenolic compounds of strawberry was performed. TWWs complied the Italian ministerial decree 185/2003 for wastewater reuse, with very few exceptions, mainly represented by chloride concentrations (258-643 mg L-1 versus a legal threshold of 250 mg L-1 ). The reuse of TWWs reduced fruit yield (10-26%) compared to irrigation with tap water as a control. Irrigation with TWWs gave also rise to the decrease of total sugars (14-26%), TSP (2-10%) and TMA (29-49%). Individual phenolic acids, flavonols and flavanols were quite stable in response to the irrigation with TWWs, whereas anthocyanidins decreased significantly. Although TWWs negatively affected fruit quality, the nutritional and nutraceutical parameters determined in the present study were in line with data previously reported for strawberries purchased in the market or cultivated in research orchards, thus suggesting that the use of TWWs does not prevent the fruit marketability. © 2020 Society of Chemical Industry.