‘Lemonato’ is a Greek peach melting-flesh white-flesh cultivar with high nutritional value highly appreciated by the consumers. This study aimed to evaluate the effect of pre-harvest foliar calcium application on fruit quality, primary metabolite profile, antioxidant activity, total phenolic content, and phenolic profile of the ‘Lemonato’ peach, clone ‘Stamatis’. The experiment was conducted for two years, 2019 and 2020, in two commercial orchards at Kato Lehonia and Agios Vlasios regions, central Greece, where the ‘Lemonato’ clone ‘Stamatis’ is traditionally cultivated. The treatments were organic calcium (Ca), calcium–silicate in nanoparticles (Ca–Si), and calcium chloride (CaCl₂). Foliar application of the different Ca formulations, commonly used as a horticultural practice, were not effective at improving the fruit quality characteristics in this clone, which is characterized by fruit softening during ripening. The study revealed the sugars and organic acid composition and phenolic profile of the ‘Lemonato’ peach, clone ‘Stamatis’. Peach fruit quality, primary metabolites, and phenolic compounds of the two orchards showed a different response to organic Ca and Ca–Si, indicating that genetic or environmental factors may also be involved. A higher concentration of organic Ca and CaCl₂ increased the peach fruit phenolic compounds content and the total antioxidant activity, improving the fruit nutritional quality.

Throughout peach orchards in Greece, plant protection, fertilization and irrigation are often conducted empirically, negatively affecting energy use efficiency and greenhouse gas emissions (GHG emissions). The aim of this study was to apply alternative fertilization and irrigation practices in canning peach orchards to improve nutrient and irrigation water management and to assess yield, energy input–output and the carbon footprint of the alternative cultivation practices for three important clingstone cultivars of different ripening periods. Energy use analysis revealed that the cultivation practice with the highest energy use was almost always irrigation, followed by fertilization, plant protection, weed control and pruning. Electricity, fuels, fertilizers and machinery presented the highest energy requirements. Alternative fertilization, in combination with deficit irrigation (DI), was more energy efficient compared to farmers’ practices in all cultivars based on energy use efficiency, energy productivity and specific energy. Irrigation was the cultivation practice with the highest impact on GHG emissions due to electricity and, secondly, to fuel consumption. Alternative fertilization and DI decreased the intensity (kg CO₂eq kg⁻¹) of the emitted GHG compared to farmers’ practices. In conclusion, alternative fertilization and irrigation practices improved energy use efficiency and decreased the carbon footprint of the canning peach orchards by improving yield and decreasing fertilizer and irrigation water input.

Almonds are one of the most popular nuts, cultivated in countries with Mediterranean climates. In an almond orchard of the self-incompatible cultivar ‘Ferragnes’ in Greece, a tree with different morphological characteristics and signs of self-compatibility was observed. The aim of this study was to study the phenotype, investigate the self-compatibility trait, and elucidate the phylogenetic background of this tree, named ‘Mars’. Morphological traits and kernel and nut characteristics were measured in ‘Mars’, ‘Ferragnes’, ‘Tuono’, and ‘Lauranne’ cultivars. The self-compatibility trait of almonds is attributed to the S_f allele; thus, its existence was investigated in ‘Mars’ by PCR amplification. Moreover, the S-RNase genes of all the cultivars were sequenced. The genetic profile of ‘Mars’ was identified using eight SSR molecular markers and compared with the ‘Ferragnes’, ‘Ferraduel’, ‘Texas’, ‘Tuono’, and ‘Lauranne’ cultivars. The morphological traits suggest that ‘Mars’ is more similar to the ‘Ferragnes’ cultivar, while it bears the S_f allele. S-RNases sequencing revealed that ‘Mars’ has the genotype S₁S_f, and the SSR markers showed that it is differentiated genetic material, suggesting it is a cross between ‘Ferragnes’ and ‘Tuono’. Therefore, ‘Mars’ is evaluated as a self-compatible variety with interesting agronomic traits for use in new mono-cultivar almond plantations.

As consumer preferences tend toward safer, chemical residue-free, and nutritionally rich fruits, preharvest bagging has gained attention as a sustainable method for improving fruit quality and protecting produce from environmental and biological stressors and pesticide residues. This study assessed the impact of preharvest bagging using paper bags with inner aluminum coating on the physicochemical traits, storability, and browning susceptibility after cutting or bruising of ‘Afrata Volou’ quince (Cydonia oblonga Mill.) fruit grown in central Greece. Fruits were either bagged or left unbagged approximately 60 days before harvest, and evaluations were conducted at harvest and after three months of cold storage, plus two days of shelf-life. Fruit bagging reduced the quince’s flesh temperature on the tree crown. Bagging had minor effects on fruit and nutritional quality, except for more yellow skin and higher titratable acidity (TA). Also, at harvest, bagging did not significantly affect fruit flesh browning after cutting or bruising. After three months of storage, unbagged and bagged quince fruit developed more yellow skin color, without significant alterations in most quality characteristics and nutritional value, but increased total tannin content (TTC). After three months of storage, the quince flesh color determined immediately after cutting or bruising was brighter and more yellowish compared to that at harvest, due to continuation of fruit ripening, but it darkened faster with time after cutting or skin removal. Therefore, fruit bagging appears to be a sustainable practice for improving the aesthetic and some chemical quality characteristics of quince, particularly after storage, without negative impacts on other characteristics such as texture and phenolic content.

Open-source devices are nowadays used in a vast number of research fields like medicine, education, agriculture, and sports, among others. In this work, an open-source, portable, low-cost pH logger, appropriate for in situ measurements, was designed and developed to assist in experiments on agricultural produce manufacturing. Τhe device was calibrated manually using pH buffers for values of 4.01 and 7.01. Then, it was tested by manually measuring the pH from the juice of citrus fruits. A waterproof temperature sensor was added to the device for temperature compensation when measuring the pH. A formal method comparison process between the open-source device and a Hanna HI9024 Waterproof pH Meter was designed to assess their agreement. We derived indices of agreement and graphical assessment tools using mixed-effects models. The advantages and disadvantages of interpreting agreement through the proposed procedure are discussed. In our illustration, the indices reported mediocre agreement and the subsequent similarity analysis revealed a fixed bias of 0.22 pH units. After recalibration, agreement between the devices improved to excellent levels. The process can be followed in general to avoid misleading or over-simplistic results of studies reporting solely correlation coefficients for formal comparison purposes.

The impact of different maturity levels of peaches on fruit quality, metabolic pattern and transcriptomic alternation was studied. To achieve this, ‘Lemonato’ peaches were sampled at commercial harvest time and then were separated based on their peel ground color into immature (light green exocarp), semi-mature (partly yellow exocarp) and mature (entirely yellow exocarp). Data indicated that several key maturity parameters, such as color index, fruit firmness, chlorophyll content, dry matter, total phenol content and antioxidant activity were notably induced by the maturity transition. Consistent with this observation, increased levels of phenolic compounds, including catechin, epicatechin, procyanidin B1/B2/B4 and chlorogenic acid, were identified at the last maturity stage. Mature fruit was also characterized by an elevated abundance of various primary metabolites (e.g. sorbitol, arabinose, xylose) and decreased levels of main organic acids and putrescine. Genes predominantly associated with flavonoid biosynthesis, calcium signaling, cell wall integrity, auxin metabolism, and aquaporins and chloroplast function were remarkably affected by maturity. Several genes were also identified (e.g. EXORDIUM , PCC13-62 and SDI1 ), including transcription factors, such as IBH1, homeobox ATHB-13 and bHLH63 , undergoing major changes during fruit maturation. These results enhance understanding of on-tree metabolic and transcriptomic events that coordinate peach fruit maturation, helping to identify the optimal harvest time for best peach fruit quality. Clinical trial number Not applicable.