Trends and challenges on peach fruit production and postharvest

The X International Peach Symposium, held under the high patronage of the International Society for Horticultural Science, ISHS, allowed to know trends and challenges for the peach industry by mains specialists in different knowledge areas, based worldwide. The conveners, Dr. George Manganaris (2nd. picture), Department of Agricultural Sciences, Biotechnology and Food Science, Cyprus University of Technology, and Dr. Athanassios Molassiotis, Department of Horticulture and Viticulture, Aristotle University of Thessalonik, organized originally the X International Peach Symposium to be held in Naoussa, Greece. They explained ?Naoussa is one of the most emblematic and beautiful cities of Greece and the place where Aristotle, the greatest philosopher of antiquity taught the ideals of Platonic philosophy to the Alexander the Great. It is also the epicenter of peach fruit production in Greece with a leading position in the canning industry, worldwide.? Due the Covid-19 pandemia it was not possible to afford the original program, which included an attractive cultural and social program, beside an high quality scientific program.? The Symposium was held online, respecting the original data, 30 May 2022 to 3 June 2022, as a webinar named ?Current trends and challenges of peach fruit production?.? Follows a short text about the key findings discussed during the Symposium and attached an extended information about them both by Dr. Manganaris, arranged by Breeding, Quality attributes, Training systems, Cultivation practices, Disease management, and Pest management.At the end of the text, also the link to the videos of the Peach Webinars. ? BreedingThe advancement of genomic technologies coupled with the drastic reduction in sequencing costs have provided unprecedented opportunities to rapidly understand the linkage between genetics, environment and the phenotypes for peach crops. Nowadays, the breeding efficiency allows the selection of individuals with desirable trait profile during early stages and field evaluations are focused on those that have the desired combination of traits. Furthermore, the impact of somatic mutations in peach breeding was highlighted, while studies, involving layer-specific whole genome sequencing will assist to quantify and understand such mechanisms. In the case of Breeding of peaches for processing, the relatively lower value of the product necessitates greater production efficiencies including higher productivity over a longer productive life for the orchard, and lower costs, particularly for labor. The bulk handling, including mechanical harvest, transport and processing make cultivar development and testing more similar to nut crops such as almond. Cultivated almond and its wild relatives also offer novel and useful genetic solutions to current and emerging processing peach needs.? Quality attributesTo improve peach fruit quality the influence of preharvest factors on fruit quality development and metabolism must be clearly understood and accurately quantified. Traditional fruit quality and maturity assessment methods are destructive, labor intensive and are not friendly for field use and large-scale data acquisition. The development of novel non-destructive techniques using visual-near infrared radiation (Vis-NIR) to accurately estimate tree-fruit quality on-tree (dry matter content (DMC), soluble solids concentration (SSC)), can support growers and researchers on decisions regarding the proper harvest time, on the evaluation of cultural techniques, new cultivars, and rootstocks towards increasing orchard quality potential As metabolite & transcript databases become larger, we will have more chances to identify markers for peach quality improvement. Programs for quality improvement are necessary to increase peach consumption for healthy diets around the world. We should advance in the integration of knowledge from different groups involved in peach research, combining datasets collected by different groups and establishing standards for data collection and formatting. These data should be loaded in an open-shared platform.? Training systemsMoving from vigorous rootstocks in low density ?3D? orchards to medium vigor ones in high density ?2D? orchards improve air and light distribution in the canopy but it requires more attention to water supply and fertilization. Minimal winter and green pruning in intensive orchards with simple training systems seems to be the possible ?golden rule? for improving the protected fruit production. Green pruning boosts the control of shoot growth and leaf area while photo-selective nets can improve the environmental control against hailstorms, heavy rain and insects for sustainable high density 2D orchards. Reducing the cost of production is a need in all the producing countries because it is increasing cost and scarcity, but also the increasing difficulty to get the desired prices for growers. In peach the inputs represent around 70% of total cost of production and, among then the labour is the most important (45-50%). Intensification is essential to reduce the cost of training during the first years in 2D or planar canopies.Increasing restrictions or not availability of crop regulators makes necessary the use of size controlling rootstocks as in other fruit species.Early yields and efficiency in the use of inputs (labour, pesticides, fertilizers, water) is a contribution to environmental sustainability and profitable production value for growers. Future peach production need to be developed under the concept of ?sustainable intensification?, then genetics (variety/rootstock) plus technology of production will be the key for success.? Cultivation practicesArtificial intelligence and precision agriculture technologies are currently available for assessing tree nutritional status and implementing optimized fertilization. Fertilization rates should consider not only tree nutritional status the previous year and yield, but also variables such as tree age, ripening season, environmental conditions and climatic patterns, pruning intensity, and soil health and management at each orchard. Peach fruit thinning guarantee high quality fruit, but actually the fruit thinning is mainly performed by ?hand?, requires a high number of skilled labor in a short period of time and is extremely costly. In recent times the mechanical thinning was an alternative to the hand thinning although it has proven to require modification of the training system to be adapted to the ?mechanical thinning machine? and simultaneously an adaptation of the machines to the training system to obtain an appropriate result. The chemical thinning option should be the best and most cost-effective solution. Until now the lack of reliable chemicals thinners did not allow to transfer into practice the peach fruit chemical thinning. This will be made possible considering that new molecules have been released to affect flower differentiation and to control the amount of flowers the following year or to act as chemical fruitlet thinners (such as the formulate Accede, that will be release this year.? Disease managementRecent advances on peach-brown rot interactions includes the search for solutions to fight in a sustainable manner.There is a large diversity of cuticular compounds (phenolic esters of triterpenoids) and variability in contents among collections which is promising for breeding; the correlations between phenolic and triterpenoid compounds and infection traits observed along fruit development and within peach populations at maturity suggest some compounds may play a role in brown rot infection.One of the main outcomings from the field epidemiology data was the development of a prediction model for Monilinia spp. risk infection. This model was validated under semi-commercial conditions and the implementation of the model allowed to significantly reduce the number of fungicide treatments in the field. Furthermore, a wide range of environmental-friendly and effective alternative strategies to synthetic fungicides to control Monilinia spp. were developed, mainly focusing on heat treatments, including hot water, curing, radiofrequency and microwaves.Besides Monilinia fructicola, bacterial spot remains challenging to control due to lack of effective spray material and consumer demand for susceptible varieties. Tolerance to copper in Xanthomonas arboricola, the causal agent of bacterial spot, may pose additional challenges for growers in the future.? Pest managementFacilitated by global warming and changes in land use and copping practices (e.g. planting of early maturing cultivars), and intensified by global trading of fresh fruit and propagation plant materials and human mobility, biological invasions of plant pest constitute one of the main concerns of plant protection for the peach production worldwide. Out of the long list of major invasive pests for the peach production that includes beetles (e.g Aromia bungii), bugs (e.g. Halyomorpha halys) and moths (e.g. Thaumatotibia leucotreta) true fruit flies (Diptera: Tephritidae) stand out. Management of invasive fruit flies in peach producing areas should prioritize preventive measure and should address all invasion steps in a sound and cohesive approach. ? VIDEOS OF THE PEACH WEBINARS All recordings are available through the link:?https://www.youtube.com/channel/UC_mhiQXA5BL_9mjTmOrQlTQ/featured Day 1:?https://www.youtube.com/watch?v=IsCK84DVcqE Day 2:?https://www.youtube.com/watch?v=14iNS6TgUVg Day 3:?https://www.youtube.com/watch?v=wknmbj0QyRo Day 4:?https://www.youtube.com/watch?v=3w8PG3npp8k