Sanitation is a crucial postharvest operation that aims to reduce the microbiological load of harvested produce. Currently, in the southeastern United States, peach packing houses use chemical oxidizers, such as sodium hypochlorite (NaOCl) in their hydrocooling systems to treat the fruit and suppress foodborne pathogens postharvest. This study aims to evaluate the effectiveness and efficiency of a novel sanitation technology called high-oxygen water (HOW) as an alternative to NaOCl. It is based on the generation of stable nanobubbles of oxygen (O2) in water in combination with gaseous ozone (O3) without the need for chemicals. The suspended solution has the potential to reduce microorganism loads during the exposure period and prevent the growth of microorganisms during storage. This technology could serve as an effective sanitation treatment for peaches during hydrocooling. Peaches were treated using HOW at various concentrations of dissolved oxygen (10, 20, and 30 mg·L−1) combined with saturated (approximately 8 mg·L−1) O3. These treatments were compared with a standard NaOCl treatment (50 mg·L−1 of free chlorine). Our team evaluated the effects of HOW by assessing postharvest fruit quality changes and decay incidence over time. The results indicated that while HOW treatments showed potential in maintaining postharvest quality, high concentrations of O3 were detrimental to fruit quality, causing increased decay incidence compared with the NaOCl treatment.

We conduct a synthetic archaeological and ethnohistoric dating program to assess the timing and tempo of the spread of peaches, the first Eurasian domesticate to be adopted across Indigenous eastern North America, into the interior American Southeast by Indigenous communities who quickly "Indigenized" the fruit. In doing so, we present what may be the earliest absolute dates for archaeological contexts containing preserved peach pits in what is today the United States in the early to mid-16(th) century. Along with our broader chronological modeling, these early dates suggest that peaches were likely in the interior prior to permanent Spanish settlement in the American Southeast and that peaches spread independently of interactions with Spanish colonizers. We further argue that that eventual spread of peaches was structured exclusively by Indigenous communities and the ecologies produced through long-term Indigenous land management and land use practices, highlighting and centering the agency of Indigenous societies in the socioecological process of colonization.

Prunus serotina (black cherry) is native to America and has five subspecies: serotina, eximia, hirsuta, virens, and capuli. P. serotina subsp. capuli is found in Central and South America with superior fruits found in Ecuador. These have large, juicy, and tasty fruits used for human consumption. They are available in produce markets and have important nutraceutical properties. However, no commercial cultivars of capuli are currently available. The main goal of this research was to understand if different morphological characters can differentiate unique populations of P. serotina subsp. capuli present in Ecuador. Morphological traits (tree, leaf, and flower) of plants grown from the OP seeds of 44 capuli accessions collected from three provinces of Ecuador (Cotopaxi, Chimborazo, and Tungurahua) were characterized in 2019 and 2020. Tree measurements included the number of primary branches and growth habit. Leaf measurements included petiole length, leaf area, leaf height, leaf width, leaf apex angle, and leaf basal angle. Flower measurements included pedicel length, flower width, and flower length. Raceme length, number of racemes per branch, and number of flowers per raceme were also characterized. ANOVA were performed with significant differences observed among capuli accessions for all variables measured. No clear differences were observed across regions with PCA and cluster analysis that may support the presence of different populations.

The prediction of floral bud progression in commercial peach cultivars promotes knowledge about the adaptability of cultivars to the climatic conditions in a specific location under a climatic variability context. Phenology is relevant to improving the scheduling of cultural practices in peach orchards. This research aimed to predict the floral bud progression of three peach cultivars: ‘Harvester’, ‘Red Globe’, and ‘Rubyprince’. Floral bud progression was assessed using one-year-old shoots collected from an orchard located at the Chilton Research and Extension Center, Alabama. Samples were evaluated under laboratory and growth chamber conditions. We recorded the flower developmental stages daily to identify the transition among stages. Daily temperature records were used to estimate the heat requirement in terms of Growing Degree Days (GDD). After dormancy release, samples needed between 23 to 39 and 37 to 42 days to reach the petal fall stage for season 1 and season 2, respectively. In terms of heat requirements, cultivars needed between 425.5 to 721.5 and 684.5 to 777 GDD to end flowering. A logistic curve was adjusted to describe the growth of the different floral stages over time. The results are key to supporting peach growers in crop management practices such as orchard establishment, irrigation, fertilization, freeze and frost protection, and pollination under climate variability scenarios.

Early fruit growth in peach is characterized by cell production. Cytokinins have established roles in regulating cell division and may regulate cell production during early fruit growth. However, the role of active cytokinins and regulation of their metabolism are not well characterized in the peach fruit. In this study, fruit growth parameters, concentrations of active cytokinin bases and a cytokinin riboside, and expression of three key cytokinin metabolism-related gene families were determined during early fruit growth. Early fruit growth was associated with intensive cell production until around 40 days after full bloom. During the early stages of this period, trans-zeatin (tZ), isopentenyladenine (iP), dihydrozeatin (DHZ) and tZ-riboside (tZR), displayed higher abundance which declined rapidly by 3.5- to 16-fold during the later stages. Changes in concentration of active cytokinin bases were consistent with roles for them in regulating cell production. Expression analyses of members of cytokinin biosynthesis-related gene families, ISOPENTENYL TRANSFERASE (IPT) and LONELY GUY (LOG), further indicated that mechanisms of synthesis of cytokinin metabolites and their activation are functional within the fruit pericarp. Changes in expression of multiple members of the LOG family paralleled changes in active cytokinin concentrations. Specifically, transcript abundance of LOG3 and LOG8 were correlated with concentrations of tZ, and iP and DHZ, respectively, suggesting that the direct activation pathway is an important route for active cytokinin base synthesis during early fruit development. Transcript abundance of two CYTOKININ OXIDASE (CKX) genes, CKX1 and CKX2, was consistent with roles in cytokinin catabolism during later stages of early fruit growth. Together, these data support a role for active cytokinins synthesized in the fruit pericarp in regulating early fruit growth in peach.

Abstract Tree training systems for temperate fruit have been developed throughout history by pomologists to improve light interception, fruit yield, and fruit quality. These training systems direct crown and branch growth to specific configurations. Quantifying crown architecture could aid the selection of trees that require less pruning or that naturally excel in specific growing/training system conditions. Regarding peaches [Prunus persica (L.) Batsch], access tools such as branching indices have been developed to characterize tree‐crown architecture. However, the required branching data (BD) to develop these indices are difficult to collect. Traditionally, BD have been collected manually, but this process is tedious, time‐consuming, and prone to human error. These barriers can be circumnavigated by utilizing terrestrial laser scanning (TLS) to obtain a digital twin of the real tree. TLS generates three‐dimensional (3D) point clouds of the tree crown, wherein every point contains 3D coordinates (x, y, z). To facilitate the use of these tools for peach, we selected 16 young peach trees scanned in 2021 and 2022. These 16 trees were then modeled and quantified using the open‐source software TreeQSM. As a result, “in silico” branching and biometric data for the young peach trees were calculated to demonstrate the capabilities of TLS phenotyping of peach tree‐crown architecture. The comparison and analysis of field measurements (in situ) and in silico BD, biometric data, and quantitative structural model branch uncertainty data were utilized to determine the reconstructive model's reliability as a source substitute for field measurements. Mean average deviation when comparing young tree (YT) height was approx. 5.93%, with crown volume was approx. 13.26% across both 2021 and 2022. All point clouds of the YTs in 2022 showed residuals lower than 12 mm to cylinders fitted to all branches, and mean surface coverage greater than 40% for both the trunk and primary branching orders.

Nanocellulose is a nanostructured cellulose hydrogel produced from mechanical disintegration of cellulose, a major carbohydrate from plant cell walls. It possesses high thermal stability and low thermal conductivity, and it can be applied as a spray coating to improve cold-hardiness in dormant grape and cherry floral buds. The objective of this study was to determine the effectiveness of nanocellulose as a freeze protection strategy in peach floral buds. Fruiting wood of cultivar 'Flavorich' was collected weekly in early spring from a commercial orchard in middle Georgia. The fruiting wood was randomly placed into four different treatment groups: control (water) and three different treatment concentrations of cellulose nanofibrils (CNF) of a commercial product - "Valida 1000". The stems were placed in Styrofoam trays and sprayed with each treatment solution using a C0(2) pressurized sprayer. Samples were then cut into 5 cm stems and randomly assigned to ten different temperature treatments for a freezing tolerance test. The freezing tolerance tests were conducted by using a programable freezing chamber to decrease the air temperature inside the freezer at a rate of -4 degrees C h(-1) from -2 to -27 degrees C. The bags were taken out of the freezer at each temperature treatment and subsequently held in a refrigerator to thaw. Visual evaluations were conducted to assess the mortality rate of the floral/vegetative buds and stems. CNF provided promising results, however its effectiveness was not consistent across each evaluation date. In two evaluation dates, CNF treated vegetative buds and stems had a higher cold hardiness than the untreated samples. Additional studies will be conducted to determine the effects of nanocellulose and the optimal concentration to utilize as an active freeze protection strategy.

Duplicate peach samples were collected from the dumping and weighing areas of four fresh peach packing lines in Georgia at 0, 3, and 6 h into the packing process on 3 random packing days per operation in the summers of 2018 and 2019, along with duplicate glove samples from peach sorters and packers at the manual sorting and weighing areas. The samples were analyzed for the population of total aerobes (TA), total yeasts and molds (YM), and total coliforms (TC), as well as the incidence of thermotolerance coliforms (TTC) and Enterococci (EC). Not affected by sampling time, peach samples from the weighing area had significantly higher (P < 0.05) TA, YM, and TC counts and >5 or 3 times higher incidence of TTC or EC than those from the dumping area. The counts of TA, YM, and TC on hand gloves from peach sorters and packers were similar, but they were significantly higher at the 3 and 6 h sampling points than at the 0 h sampling point. Among analyzed glove samples, 39.39% and 7.58% tested positive for TTC or EC. Thus, packing line hygiene and hand gloves worn by peach handlers could be possible sources of fresh peach contamination.

Phenological shifts in peaches have been observed over the last few years due to the fluctuation of the seasonal climate conditions experienced during dormancy, affecting orchard management practices and influencing production and harvest dates. This study aimed to model the vegetative and floral budbreak of selected peach cultivars. Three peach cultivars, including “Rubyprince”, “Harvester”, and “Red Globe”, were considered in this study based on the representation of the early, early-mid, and mid-seasons. The prediction of the budbreak in peaches was assessed using different models that integrate the combination of chill and heat requirements. Models used include the Weinberger model, the modified Weinberger model, Utah, the dynamic model, and the growing degree model. The accumulation of chill varies according to the season evaluated. A model that considers both chill and heat accumulation is presented for each cultivar. Budbreak as an indicator of dormancy completion was established for each cultivar. The outcome of this study is to determine the amount of chilling accumulation and thermal time required to mark the beginning of the budbreak in selected cultivars with a model that predicts the duration of the dormancy. These results are valuable information that can be used for crop management practices and support the mitigation of cold damage during this critical period of crop development.