Orchard Locations Research Articles

Comparison of ethanol-baited trap designs for ambrosia beetles in orchards in the eastern United States.

Ambrosia beetles (Coleoptera: Curculionidae: Scolytinae) are among the most devastating pests of orchards, nurseries, and forests. Improving trap design and ethanol lures for capturing ambrosia beetles is necessary to develop effective monitoring and management strategies. In this 2-year study, we assessed 4 trap designs and 3 commercially formulated ethanol lures to refine trapping methods tailored for orchard environments in the eastern United States. Our investigation included orchards in 2 regions, Georgia (pecan orchards) and New York (apple orchards), targeting major ambrosia beetle (Coleoptera: Curculionidae) pest species such as Xylosandrus crassiusculus (Motschulsky), X. compactus (Eichhoff), X. germanus (Blandford), and Anisandrus maiche (Stark). Among the trap designs evaluated, clear sticky cards were most effective for capturing ambrosia beetles across orchard locations. Notably, in Georgia, sticky cards paired with specific low-release ethanol lures demonstrated enhanced capture of X. crassiusculus and X. compactus, 2 key ambrosia beetle pests found infesting young pecan trees. Similarly, in New York, sticky cards baited with low-release ethanol lures captured the highest rates of X. germanus and A. maiche, thus indicating its suitability for diverse ambrosia beetle populations. Overall, our study provides practical implications for tailoring trapping protocols to optimize ambrosia beetle management strategies in orchard settings.

Non-target impacts of hail netting and insecticides on natural enemy abundance and diversity in a Midwestern U.S. commercial apple orchard

A variety of exclusion systems for integrated pest management (IPM) have become viable alternatives to traditional insecticide use in tree fruit production globally. Exclusion netting has been particularly effective as a control strategy for several insect pests of apple. In Minnesota, USA, hail netting, used to protect high-value fruit from hail damage, was recently shown to effectively exclude the two major insect pests: codling moth (Cydia pomonella L.) and apple maggot (Rhagoletis pomonella Walsh). The present study aimed to determine the impact of single-row, drape-style hail netting (DrapeNet®) on the natural enemy community and how this compared to the impact of insecticides used by a Minnesota grower. Sampling occurred during 2021 and 2022 at two orchard locations in Minnesota using yellow sticky traps. Natural enemies were identified to the family level, and these data were examined to determine family richness, diversity, and relative abundance. Compared to unnetted rows, rows covered with hail netting had a significant reduction in both family richness and predator abundance, as measured by yellow sticky traps. The overall abundance of the three most common predator families, Anthocoridae, Empididae, and Coccinellidae, along with other families, was significantly reduced under netting. By contrast, using Simpson's diversity index we found that family diversity was significantly higher under netting, while the insecticides used did not affect diversity. These findings indicate that non-target effects of netting include a general reduction in the abundance of natural enemies and the disproportionate exclusion of Anthocoridae. However, predator diversity was higher under netting, indicating that biological control services could remain intact under netting even with modest use of insecticides.

High stand density improves seed production in seed orchards of the masting species Picea abies

Reproduction in masting species is characterised by long intervals between good cone and seed production years, and only sparse reproduction between mast years. The physiological mechanisms behind masting, and how these are linked to internal resource status and external weather factors, is still a subject of scientific exploration and debate, as is the effect of climate change on masting. This study investigates cone production in one operational seed orchard in Sweden which was established with two different spacings and has since been subject to three tree thinning experiments. The spacings before thinning varied between 800 and 400 stems ha–1, and then thinning reduced the stand density in all trials to half, i.e. between 400 and 200 stems ha–1. In all three experiments cone production per tree was equal in un-thinned and thinned treatments, both in mast years and in non-mast years. Thus, the cone production per unit area was twice as high in the un-thinned areas. The conclusion from these experiments is that the establishment of Picea abies (L.) H. Karst. seed orchards with wide tree spacing is both a misuse of good orchard locations and bad economics.

Sap flow and leaf gas exchange response to a drought and heatwave in urban green spaces in a Nordic city

Abstract. Urban vegetation plays a role in offsetting urban CO2 emissions, mitigating heat through tree transpiration and shading, and acting as deposition surfaces for pollutants. The frequent occurrence of heatwaves and of concurrent drought conditions significantly disrupts the processes of urban trees, particularly their photosynthesis and transpiration rates. Despite the pivotal role of urban tree functioning in delivering essential ecosystem services, the precise nature of their response remains uncertain. We conducted sap flux density (Js) and leaf gas exchange measurements of four tree species (Tilia cordata, Tilia × europaea, Betula pendula, and Malus spp.) located in different urban green areas (Park, Street, Forest, and Orchard) in Helsinki, Finland. Measurements were made over two contrasting summers 2020 and 2021. Summer 2021 experienced a local heatwave and drought, whereas summer 2020 was more typical of Helsinki. In this study, we aimed to understand the responses of urban tree transpiration (measured with sap flux density) and leaf gas exchange to heatwave and drought conditions, and we examined the main environmental drivers controlling the tree transpiration rate during these periods. We observed varying responses of Js during the heatwave period at the four urban sites. When comparing the heatwave and no heatwave periods, a 35 %–67 % increase in Js was observed at the Park, Forest, and Orchard locations, whereas no significant change was seen at the Street site. Our results also showed that Js was higher (31 %–63 %) at all sites under drought conditions compared with non-dry periods. The higher Js values during the heatwave and dry periods were mainly driven by the high atmospheric demand for evapotranspiration, represented by the high vapor pressure deficit (VPD), suggesting that the trees were not experiencing severe enough heat or drought stress that stomatal control would have decreased transpiration. Accordingly, photosynthetic potential (Amax), stomatal conductance (gs), and transpiration (E) at the leaf level did not change during heatwave and drought periods, excluding the Park site where a significant reduction in gs was seen. VPD explained 55 %–69 % of the variation in the daily mean Js during heatwave and drought periods at all sites. At the Forest site, the increase in Js saturated after a certain VPD level, likely due to low soil water availability during these hot and dry periods. Overall, the heat and drought conditions were untypical of the region but not excessive enough to restrict stomatal control and transpiration, indicating that ecosystem services such as cooling were not at risk.

Temporal transcriptome and metabolite analyses provide insights into the biochemical and physiological processes underlying endodormancy release in pistachio (Pistacia vera L.) flower buds.

Pistachio (Pistacia vera L.), an economically and nutritionally important tree crop, relies on winter chill for bud endodormancy break and subsequent blooming and nut production. However, insufficient winter chill poses an increasing challenge in pistachio growing regions. To gain a better understanding of the physiological and biochemical responses of endodormant pistachio buds to chilling accumulation, we investigated the global gene expression changes in flower buds of pistachio cv. Kerman that were cultivated at three different orchard locations and exposed to increasing durations of winter chill. The expression of genes encoding β-1,3-glucanase and β-amylase, enzymes responsible for breaking down callose (β-1,3-glucan) and starch (α-1,4-glucan), respectively, increased during the endodormancy break of pistachio buds. This result suggested that the breakdown of callose obstructing stomata as well as the release of glucose from starch enables symplasmic trafficking and provides energy for bud endodormancy break and growth. Interestingly, as chilling accumulation increased, there was a decrease in the expression of nine-cis-epoxycarotenoid dioxygenase (NCED), encoding an enzyme that uses carotenoids as substrates and catalyzes the rate-limiting step in abscisic acid (ABA) biosynthesis. The decrease in NCED expression suggests ABA biosynthesis is suppressed, thus reducing inhibition of endodormancy break. The higher levels of carotenoid precursors and a decrease in ABA content in buds undergoing endodormancy break supports this suggestion. Collectively, the temporal transcriptome and biochemical analyses revealed that the degradation of structural (callose) and non-structural (starch) carbohydrates, along with the attenuation of ABA biosynthesis, are critical processes driving endodormancy break in pistachio buds.

Factors affecting development of disorders expressed after storage of ‘Gala’ apple fruit

This study investigated factors influencing susceptibility and development of physiological disorders and decay expressed after long-term storage in ‘Gala’ apple fruit (Malus domestica Borkh.). Five experiments were performed over ten production years with fruit from two environmentally different orchard locations in a humid subtropical climate at 990 m (warmer) and 1415 m above sea level. Fruit were harvested at two maturity stages (early and advanced), treated or not treated with 1-methylcyclopropene (1-MCP) and stored at 0.5 °C or 2 °C in a controlled atmosphere (CA, 1.5 kPa O2 and 2.5 kPa CO2), for 240 d plus 7 d shelf life. In one experiment, fruit were stored in CA with CO2 concentrations of 1.5 or 3 kPa. The relationship between fruit mineral composition and physiological disorders was assessed in one production year. Flesh browning (FB) was the predominant disorder, followed by decay, cracking, and lenticel breakdown-wet (LB-wet). The average severity index of lenticel breakdown-dry (LB-dry), leather blotch and bitter pit were low and variable across production years. The FB index was lowest in fruit produced at the colder orchard location, early harvest, treatment with 1-MCP, and storage at 2 °C. These factors also influenced fruit softening after storage. The major source of variance of the FB index in order of decreasing contribution were harvest maturity, production year, orchard location, 1-MCP and storage temperature. Production year variability of FB index correlated positively with early summer rain and negatively with early spring temperature. A weak positive correlation was also found between FB index and fruit K+Mg/Ca ratio. Higher CA CO2 concentration increased FB in fruit stored at 0.5 °C but not at 2 °C. The same factors affected decay, cracking and LB-wet disorder similarly as for FB, except that decay and cracking were not consistently affected by storage temperature, and decay and LB-wet were not impacted by 1-MCP. Storage temperature had the most influence on the variance of LB-wet. LB-dry was highest in late harvest fruit and, in the production year with the highest index, in fruit stored at 0.5 °C. Leather blotch was highest in early harvest fruit and in fruit stored at 0.5 °C. 1-MCP treatment did not affect disorders other than FB and cracking. These results suggest that interactions among harvest and postharvest factors influence the development of ‘Gala’ FB and other disorders and indicate a possible relationship of chilling in FB development. The information may be useful for implementing practical strategies to reduce the development of these postharvest disorders in ‘Gala’ apple fruit.

Population Dynamic and Distribution of Bactrocera carambolae and Bactrocera dorsalis in Orchard Habitat in Different Geographical Areas

Fruitflies, particularly Bactrocera carambolae and Bactrocera dorsalis, are significant pests that have the potential to diminish the quality and quantity of agricultural products. They may live in diverse habitats, particularly in agroecosystem habitats. Orchard habitats offer a source of food and development for fruit flies like B. carambolae and B. dorsalis not only in Java, notably Majalengka Regency, but also in Lombok Island and West Nusa Tenggara. Consequently, the purpose of there search is to observe (1) The population dynamic of B. carambolae and B. dorsalis in the orchard habitat. (2) Distribution of fruit flies B. carambolae and B. dorsalis trapping results in the orchard habitat. (3) Analyzing the factors affecting the presence of the fruit fly species B. carambolae and B. dorsalis in the orchard habitat. Fruitflies were sampled using the trap method between December 2021 and March 2022. In the orchard habitat on the mangosteen fruit commodity, the results indicated that B. carambolae and B. dorsalis had the largest population densities. Additionally, orchard locations on Lombok Island had the highest population density. Furthermore, fruitflies are more prevalent in perennial crops than in annual ones due to higher population density. Perennial crops are the ideal conditions for fruit fly development as compared to seasonal crops.

Population Dynamic and Distribution of Bactrocera carambolae and Bactrocera dorsalis in Orchard Habitat in Different Geographical Areas

Fruitflies, particularly Bactrocera carambolae and Bactrocera dorsalis, are significant pests that have the potential to diminish the quality and quantity of agricultural products. They may live in diverse habitats, particularly in agroecosystem habitats. Orchard habitats offer a source of food and development for fruit flies like B. carambolae and B. dorsalis not only in Java, notably Majalengka Regency, but also in Lombok Island and West Nusa Tenggara. Consequently, the purpose of there search is to observe (1) The population dynamic of B. carambolae and B. dorsalis in the orchard habitat. (2) Distribution of fruit flies B. carambolae and B. dorsalis trapping results in the orchard habitat. (3) Analyzing the factors affecting the presence of the fruit fly species B. carambolae and B. dorsalis in the orchard habitat. Fruitflies were sampled using the trap method between December 2021 and March 2022. In the orchard habitat on the mangosteen fruit commodity, the results indicated that B. carambolae and B. dorsalis had the largest population densities. Additionally, orchard locations on Lombok Island had the highest population density. Furthermore, fruitflies are more prevalent in perennial crops than in annual ones due to higher population density. Perennial crops are the ideal conditions for fruit fly development as compared to seasonal crops.

Surveillance for Avocado Sunblotch Viroid Utilizing the European Honey Bee (Apis mellifera).

Avocado is one of the world's fastest growing tropical fruit industries, and the pathogen avocado sunblotch viroid (ASBVd) is a major threat to both production and access to international export markets. ASBVd is seed transmissible, with infection possible via either the male (pollen) or female gametes. Surveillance for ASBVd across commercial orchards is a major logistical task, particularly when aiming to meet the stringent standards of evidence required for a declaration of pest freedom. As with many fruit crops, insect pollination is important for high avocado yields, and honey bee (Apis mellifera) hives are typically moved into orchards for paid pollination services. Exploiting the foraging behavior of honey bees can provide a complementary strategy to traditional surveillance methods. High-throughput sequencing (HTS) of bee samples for plant viruses shows promise, but this surveillance method has not yet been tested for viroids or in a targeted plant biosecurity context. Here, we tested samples of bees and pollen collected from pollination hives in two ASBVd orchard locations, one in Australia, where only four trees in a block were known to be infected, and a second in South Africa, where the estimated incidence of infection was 10%. Using real-time RT-PCR and HTS (total RNA-seq and small RNA-seq), we demonstrated that ASBVd can be confidently detected in bees and pollen samples from hives within 100 m of infected trees. The potential for using this approach in ASBVd surveillance for improved orchard management and supporting market access is discussed.

Impacts of abiotic factors on the fungal communities of 'Honeycrisp' apples in Canada.

The maintenance of the beneficial plant microbiome to control plant pathogens is an emerging concept of disease management, and necessitates a clear understanding of these microbial communities and the environmental factors that affect their diversity and compositional structure. As such, studies investigating the microbiome of economically significant cultivars within each growing region are necessary to develop adequate disease management strategies. Here, we assessed the relative impacts of growing season, management strategy, and geographical location on the fungal microbiome of 'Honeycrisp' apples from seven different orchard locations in the Atlantic Maritime Ecozone for two consecutive growing years. Though apple fruit tissue was dominated by relatively few fungal genera, significant changes in their fungal communities were observed as a result of environmental factors, including shifts in genera with plant-associated lifestyles (symbionts and pathogens), such as Aureobasidium, Alternaria, Penicillium, Diplodia, and Mycosphaerella. Variation in fungal composition between different tissues of fruit was also observed. We demonstrate that growing season is the most significant factor affecting fungal community structure and diversity of apple fruit, suggesting that future microbiome studies should take place for multiple growing seasons to better represent the host-microbiome of perennial crops under different environmental conditions.

Six years of wild bee monitoring shows changes in biodiversity within and across years and declines in abundance.

Wild bees form diverse communities that pollinate plants in both native and agricultural ecosystems making them both ecologically and economically important. The growing evidence of bee declines has sparked increased interest in monitoring bee community and population dynamics using standardized methods. Here, we studied the dynamics of bee biodiversity within and across years by monitoring wild bees adjacent to four apple orchard locations in Southern Pennsylvania, USA. We collected bees using passive Blue Vane traps continuously from April to October for 6 years (2014–2019) amassing over 26,000 bees representing 144 species. We quantified total abundance, richness, diversity, composition, and phylogenetic structure. There were large seasonal changes in all measures of biodiversity with month explaining an average of 72% of the variation in our models. Changes over time were less dramatic with years explaining an average of 44% of the variation in biodiversity metrics. We found declines in all measures of biodiversity especially in the last 3 years, though additional years of sampling are needed to say if changes over time are part of a larger trend. Analyses of population dynamics over time for the 40 most abundant species indicate that about one third of species showed at least some evidence for declines in abundance. Bee family explained variation in species‐level seasonal patterns but we found no consistent family‐level patterns in declines, though bumble bees and sweat bees were groups that declined the most. Overall, our results show that season‐wide standardized sampling across multiple years can reveal nuanced patterns in bee biodiversity, phenological patterns of bees, and population trends over time of many co‐occurring species. These datasets could be used to quantify the relative effects that different aspects of environmental change have on bee communities and to help identify species of conservation concern.

Influence of irrigation regime on gas exchange, growth, and oil quality of field grown, Texas (USA) olive trees

Abstract Olive (Olea europaea L.) oil production is an emerging industry in Texas (USA). However, limited research has been conducted to determine best irrigation practices for Texas growers. In this study, established “Arbequina” olive trees from three south Texas orchard locations were used to investigate effects of irrigation volume on olive tree gas exchange, growth, and oil quality. Twelve-year-old trees were exposed to three irrigation regimes. Over the course of two growing seasons, leaf gas exchange, shoot growth, and oil quality were measured. Data from a single orchard and growing season are presented. Differences in monthly and overall leaf gas exchange data were not found. Based on soil surface area under each tree’s dripline, depth of total water applied to each tree (irrigation plus precipitation) ranged from 1,451 (three-emitter irrigation treatment) to 759 mm (one-emitter irrigation treatment). Trees exposed to the three-emitter irrigation treatment produced the greatest shoot growth. Fruit mass and fruit volume were greatest for trees which had the fewest emitters (lowest irrigation volumes). Oil pressed from each experimental tree rendered extra virgin olive oil. Oil chemical analysis indicates total phenols tended to be greatest from trees receiving the least volume of irrigation. For Texas olive growers, research suggests there are opportunities to reduce irrigation, yet maintain olive oil quality.

Canopy Position Affect Rind Biochemical Properties of ‘Marsh’ Grapefruit during Postharvest Cold Storage at Non-chilling Temperature

ABSTRACT Effect of canopy position on rind biochemical properties of ‘Marsh’ grapefruit during postharvest non-chilling cold storage was evaluated on fruit harvested from different orchard locations. Inside canopy (IC) and outside canopy (OC) fruits were harvested at commercial maturity from two commercial farms located at KwaZulu-Natal (KZN) and Limpopo (LMP), South Africa, during two seasons. Rind biochemical analyses including color indices, total phenolic concentration, and sugars were performed on harvested grapefruit after Weeks 0, 3, 6, and 9 of cold storage at 7.5 ± 0.5°C. Canopy position showed a high significant (p < .001) effect on rind biochemicals while significant (p < .05) influence of orchard locations was observed on the same parameters. Reducing sugars were more concentrated in IC fruit harvested from both orchard location than OC fruit at Weeks 0 and 3, but inverse results occurred at Weeks 6 and 9. Orchard location significantly (p < .001) influenced vitamin C (14.4, 14.2, 14.4, 14.8 g kg−1) and (12.3, 16.1, 15.9, 14.6 g kg−1) of fruit rind at Weeks 0, 3, 6, and 9 from KZN and LMP, respectively. This study revealed that canopy position can influence rind biochemical properties of ‘Marsh’ grapefruit during non-chilling postharvest cold storage. However, further studies are required to formulate and provide the citrus industries with adequate advice.

Tissue age, orchard location and disease management influence the composition of fungal and bacterial communities present on the bark of apple trees.

Plants host microbial communities that can be affected by environmental conditions and agronomic practices. Despite the role of bark as a reservoir of plant pathogens and beneficial microorganisms, no information is available on the effects of disease management on the taxonomic composition of the bark-associated communities of apple trees. We assessed the impact of disease management strategies on fungal and bacterial communities on the bark of a scab-resistant apple cultivar in two orchard locations and for two consecutive seasons. The amplicon sequencing revealed that bark age and orchard location strongly affected fungal and bacterial diversity. Microbiota dissimilarity between orchards evolved during the growing season and showed specific temporal series for fungal and bacterial populations in old and young bark. Disease management did not induce global changes in the microbial populations across locations and seasons, but specifically affected the abundance of some taxa according to bark age, orchard location and sampling time. Therefore, the disease management applied to scab-resistant cultivars, which is based on a limited use of fungicides, partially changed the taxonomic composition of bark-associated fungal and bacterial communities, suggesting the need for a more accurate risk assessment regarding possible pathogen outbreaks.

Attraction of Stink Bug (Hemiptera: Pentatomidae) Nymphs toEuschistusAggregation Pheromone in the Field

Abstract Phytophagous stink bugs (Hemiptera: Pentatomidae) are primary pests in most fruit, vegetable, grain, and row crops worldwide. Pheromones have been identified and synthesized for several species of economically important stink bug pests. When yellow pyramid traps are baited with lures containing these pheromones, significantly more stink bug adults are captured in the field than without lures. Our specific objective for this study was to examine the attractiveness of the Euschistus aggregation pheromone, methyl (E,Z)-2,4-decadienoate (MDD), to stink bug nymphs by using yellow pyramid traps baited and not baited with MDD lures in peanut fields and alongside pecan and peach orchards. At orchard locations, captured nymphs were predominantly Euschistus servus (Say) followed by E. tristigmus (Say), E. ictericus (L.), and Thyanta custator custator (F.). In peanut, E. servus, E. tristigmus, and Chinavia hilaris (Say) nymphs were caught in traps. Nymphal capture of E. servus, E. tristigmus, and C. hilaris...

Quantification of bioactive compounds in Picual and Arbequina olive leaves and fruit

Olive leaves and fruit possess bioactive substances such as phenolic compounds and triterpenic acids that can be obtained from olive by-products generated during olive oil extraction. The aim of the present study was the characterization and quantification of these compounds in Picual and Arbequina cultivars from different locations and throughout two seasons in both olive leaves and fruit. The major phenolic compound identified in the leaves was oleuropein, and the total content of phenolic compounds in this material reached 70 g kg-1 fresh weight. The leaves were also rich in triterpenic acids (20 g kg-1 fresh weight), with oleanolic acid being the most concentrated among them. With regard to olives, oleuropein and demethyloleuropein were the main phenolic compounds in the pulp of Picual and Arbequina cultivars, and the total concentration of these phenolic compounds reached 3.5% fresh weight. Olives can also be an important source of triterpenic acids, although this is mainly the skin part, where the maslinic and oleanolic acids are concentrated. Olive leaves can contain up to 70 g kg-1 phenolic compounds and 20 g kg-1 triterpenic acids, and olive fruit can contain up to 35 g kg-1 of the former and 3 g kg-1 of the latter. It must also be noted that this level was constant both between seasons and orchard locations. © 2016 Society of Chemical Industry.

Genetic Diversity and Population Structure of Fusicladium effusum on Pecan in the United States.

Fusicladium effusum causes pecan scab, which is the most destructive disease of pecan orchards in the United States. Conidia of the pathogen are spread by rain splash and wind. The fungus is pathogenically diverse; yet there is no information on its genetic diversity or population genetics. Universally primed polymerase chain reaction (UP-PCR) was used to investigate the genetic diversity and population structure on a hierarchical sample of 194 isolates collected from 11 orchard locations from Florida to Texas, consisting of three to four isolates from each of five to six trees at each location. Genetic variation was high throughout the region, with all but nine of the multilocus haplotypes being unique. Nei's average gene diversity ranged from 0.083 for a population from Mississippi to 0.160 for a population from Kansas. An analysis of molecular variance of the hierarchically sampled populations found that the majority of the genetic variability (82.6%) occurred at the scale of the individual tree and only relatively small amounts among populations in trees from an orchard (5.0%) or within groups (i.e., orchard location populations) (12.5%). The results suggest little population differentiation in F. effusum in the southeastern United States, although φpt values of genetic distance for pairwise comparisons indicated some populations could be differentiated from others. There was evidence of linkage disequilibrium in certain populations, and the common occurrence of asexual reproduction in F. effusum could lead to measurable linkage disequilibrium under certain circumstances. However, the degree of genetic diversity and the scale over which diversity is distributed is evidence that F. effusum undergoes regular recombination despite no known sexual stage.

Effect of Different Ethephon Concentrations on Olive Fruits Harvesting at Different Orchard Locations

An experiment was conducted to determine the optimum ethephon concentration on olive fruit harvesting at different Jordan locations. The study was carried out on Nabali olive cultivar at “Irbid and Ajlon” locations. Treatments were consisted of five ethephon concentrations, which are: 0, 1000, 2000, 3000 and 4000 ppm, each concentration was repeated 4 times. 10 days after ethephon applications, data were collected and analyzed according to the randomized completely block design. Results revealed that all of the used ethephon concentrations promote leaf drop, which remains within the acceptable ranges in both locations. Although, ethephon dosage had significant effects on harvesting productivity at 0.05 levels; best results were obtained by using 3000 ppm concentration at Irbid location, while at Ajlon; best results were observed with treating the olive fruits with 4000 ppm ethephon concentration. On the other hand, positive correlation were observed between the percent of leaf drop and the total harvested fruits

Effect of Different Ethephon Concentrations on Olive Fruits Harvesting at Different Orchard Locations

An experiment was conducted to determine the optimum ethephon concentration on olive fruit harvesting at different Jordan locations. The study was carried out on Nabali olive cultivar at “Irbid and Ajlon” locations. Treatments were consisted of five ethephon concentrations, which are: 0, 1000, 2000, 3000 and 4000 ppm, each concentration was repeated 4 times. 10 days after ethephon applications, data were collected and analyzed according to the randomized completely block design. Results revealed that all of the used ethephon concentrations promote leaf drop, which remains within the acceptable ranges in both locations. Although, ethephon dosage had significant effects on harvesting productivity at 0.05 levels; best results were obtained by using 3000 ppm concentration at Irbid location, while at Ajlon; best results were observed with treating the olive fruits with 4000 ppm ethephon concentration. On the other hand, positive correlation were observed between the percent of leaf drop and the total harvested fruits

Assessment of rind quality of ‘Nules Clementine’ mandarin fruit during postharvest storage: 2. Robust Vis/NIRS PLS models for prediction of physico-chemical attributes

The robustness of visible to near infrared spectroscopy (Vis/NIRS) models is a crucial requirement for assessment of fruit quality parameters. This study was conducted to investigate the performance of partial least squares (PLS) models developed with data from individual orchard locations with those developed from combined orchard locations and two seasons in predicting postharvest rind physico-chemical properties related to susceptibility of ‘Nules Clementine’ mandarins to progressive rind breakdown disorder (RBD). Vis/NIRS signals were acquired on freshly harvested fruit and reference physico-chemical properties were measured after 8 weeks of storage at 8±0.5°C, including incidence of RBD, rind hue angle (h°), rind dry matter, and non-structural carbohydrates (sucrose, glucose, fructose, total carbohydrates) concentration. PLS regression with leave-one-out full cross validation was used to develop calibration models of studied parameters. The models were externally validated using data from a different location or season not included in the calibration. Prediction performance of PLS models of a single orchard location validated with data of an independent location was low but encouraging, with residual predictive deviation (RPD) values ranging from 0.95 to 1.58 for fructose models. The fructose calibration models developed using two combined orchard locations had higher prediction accuracy (RPD ranging between 1.32 and 1.97) than models of one orchard location. The performance of models developed from three orchard locations in 2012 to predict parameters of 2011 was better (RPD for fructose model=2.50) than models developed from individual orchards and two combined orchards. Results from this study demonstrated that Vis/NIRS models offer considerable robustness for non-invasive prediction of rind quality attributes which might predispose ‘Nules Clementine’ mandarin fruit to RBD.