Sergio Tombesi

• Agricultural sciences Ph.D.
• Professor (Associate) at Università Cattolica del Sacro Cuore

High-density olive groves, despite their interesting production potential, have several limitations, including their high fruit load and irrigation requirements. This study aimed to evaluate the effects of fruit load and deficit irrigation on oil yield, fruit quality, and olive chemical composition in a high-density olive grove (cv Sikitita). Our m...

Hazelnut (Corylus avellana) cultivation is increasing worldwide. A 3D model of its structure could improve the managerial techniques such as pruning. This study aims to analyse, over two successive years, hazelnut architectural development to implement a functional structural plant model. 104 one-year-old shoots of own-rooted hazelnut trees were se...

Relative growth rate (RGR) is a standardized measure of growth that accounts for the difference in initial organ size. RGR sets their sink strength potential that, in combination with dark respiration (Rd), determines the carbon need of organs. Total Rd is the sum of maintenance respiration (Rm) and growth respiration (Rg). The first provides energ...

Trunk shakers perform a forced vibration that should be set according to tree species and architecture to efficiently detach fruits. However, manufacturing companies produce designs that are poorly customisable according to different trees. This work presents a prototype that is configurable in amplitude and frequency of vibration, which has been d...

The application of vibration in the mechanical harvesting of fruit trees is a determining factor to achieve fruit detachment. The acceleration required to do so is experimentally determined in expensive tests using different machines and configurations. A simple, appropriate model that could predict the vibration response of plant matter might faci...

At springtime, the formation of stem somatic traits (stem elongation and leaf growth) and reproductive activity (flowering and fruit set) occur simultaneously. They are all competing carbon sinks, with an extremely high demand for carbohydrates. The shoot growth rate is strongly related to environmental temperature, which, according to climate chan...

Italian olive growing must aim at the transition to economically and environmentally sustainable management systems, linked to premium quality production and to a recognized and remunerated context of biodiversity conservation in compliance with the provisions of the European Union New Green Deal and United Nations Agenda 2030. To assist and facili...

Dark respiration (Rd) is a fundamental plant process used to gain biomass and maintain plant physiological activity. It accounts for the metabolization of a large share of the carbon fixed by photosynthesis. However, Rd during conditions of severe plant water stress is still poorly understood. The decrease in leaf transpiration increases temperatur...

In this study, grafted and own-rooted young hazelnut plants of three high-quality cultivars were cultivated in Central Italy to investigate possible differences in growth, fruit and flower production, and physiological processes encompassing water uptake, photosynthetic variables, and non-structural carbohydrates (NSC) allocation. Stable isotopes a...

Understanding the interaction between insects and microclimate can be essential in order to plan informed and efficient treatments against agricultural pests. Microclimatic factors such as humidity and temperature can influence the population dynamics of the invasive agricultural pest Halyomorpha halys, the brown marmorated stink bug. The aim of th...

Functional structural plant models of tree crops are useful tools that were introduced more than two decades ago. They can represent the growth and development of a plant through the in silico simulation of the 3D architecture in connection with physiological processes. In tree crops, physiological processes such as photosynthesis, carbon allocatio...

Climate change scenarios and the need of sustainable tools to reduce global warming impact on agriculture have led to the formulation of a large number of natural products or biostimulants that should increase plant resilience to abiotic stress. Ascophyllum nodosum (AN) extract is one of the most studied biostimulants to increase tolerance to droug...

Biostimulants have recently been used in sustainable agriculture systems to improve plant growth and resilience to biotic and abiotic stress. In this study, foliar (ANEfl) and soil (ANEsl) A. nodosum extract applications were studied to elucidate the impact of different delivery methods on grapevines physiology either under well-watered conditions...

In zone frequentemente soggette a stress multipli estivi e per la combinazione con vitigni particolarmente sensibili alla carenza idrica, viti innestate su M4 hanno dimostrato di poter mantenere uno stato idrico migliore, una migliore funzionalità della chioma e una maggior efficienza di uso dell’acqua rispetto a viti innestate su portinnesti tradi...

The foreseen increase in evaporative demand and reduction in rainfall occurrence are expected to stress the abiotic constrains of drought and salt concentration in soil. The intensification of abiotic stresses coupled with the progressive depletion in water pools is a major concern especially in viticulture, as most vineyards rely on water provided...

Early leaf removal (ELR) applied in the grapevine cluster zone at bloom or pre-bloom (PB) is a vineyard practice commonly utilized to reduce fruit disease and yield. In addition, the literature reports that ELR enhances fruit quality, however, little research has deciphered the potential factors regulating this response. In this work, the objective...

In many viticulture regions, multiple summer stresses are occurring with increased frequency and severity because of warming trends. Kaolin-based particle film technology is a technique that can mitigate the negative effects of intense and/or prolonged drought on grapevine physiology. Although a primary mechanism of action of kaolin is the increase...

A novel bud-forcing technique aimed at obtaining two crops (primary and forced) within the same season was tested on potted Pinot noir grapevines. Removing young, vegetative organs from primary shoots trimmed to six nodes in early summer allows dormant buds to break para-dormancy, leading to a delayed, second crop. Meanwhile, the primary crop is le...

M4 is a relatively new rootstock that was selected for increased resilience of vineyards across hot regions where meteorological drought is often coupled to water scarcity. However, M4 has thus far been tested only against water-stress sensitive rootstocks. Against this backdrop, the aim of the present work is to examine the water status and gas ex...

The aim of the study was to verify if a new kaolin formulation, which contains 100% aluminium silicate, can reduce the negative effects of high summer temperatures and heat stress on canopy physiological processes, yield and fruit quality in hazelnut (Corylus avellana L.). Kaolin was applied on young Tonda Giffoni plants three times in 2018 summer...

BACKGROUND In the present study a metabolomics‐based approach was used to discriminate among different hazelnut cultivars and to trace their geographical origins. Ultra‐high‐pressure liquid chromatography coupled to quadrupole‐time‐of‐flight mass spectrometry (UHPLC‐ESI/QTOF‐MS) was used to profile phenolic and sterolic compounds. RESULTS Compound...

The effect of arbuscular mycorrhizal (AM) on vegetative and reproductive cycle of young hazelnut plants, cv. Tonda Giffoni, under high temperature and low water availability was investigated. Hazelnut plants were inoculated with G. iranicum for two consecutive years in spring. G. iranicum improved the leaf physiological performances, preserved the...

BACKGROUND Recent studies report that Ascophyllum nodosum extracts, once applied on the canopy of different crops, deliver positive effects, increasing yield, inducing tolerance to biotic stress, and improving the quality of products. However, the mechanisms of action are still unclear. In this research, vines subjected to multiple foliar applicati...

Kaolin applications have been investigated in grapevines to understand cooling effects on leaves and clusters and the relative impact on gas exchange, leaf biochemistry, water use efficiency, glyco-metabolism and hormonal patterns. Several Almost all previous contributions have relied upon single-leaf measurements, leaving uncertainty on whole cano...

Severe prebloom leaf removal dramatically affects the source-sink balance in grapevines, leading to a reduction in fruit set. In this study, carried on for two consecutive years, the impact of defoliation at bloom was evaluated with the objective to assess the capacity of developing inflorescences to attract photosynthates from adjacent shoots subj...

In grapevines, basal leaf removal at bloom often induces a reduction of fruit set. The effect is related to a reduction in carbon availability for different plant organs competing for photosynthates. To understand and quantify carbon allocation among major sink organs following the early basal leaf removal, the effect of early basal defoliation was...

The aim of the study was to verify if vineyard kaolin application during the 2017 hot summer could reduce the negative effects of high temperatures and heat stress on canopy physiological processes, yield and fruit quality. The kaolin was applied once at the beginning of August, at 3% concentration, in a Pinot Noir vineyard. The application was per...

During the spring of 2016, one-year-old own-rooted and 3-year-old grafted vines of cv. Sangiovese were treated with MycoUp, a formulation based on a recently identified mycorrhizal fungus, Glomus iranicum var. tenuihypharum sp. nova. The results are showing an impact on the development of the root system of the two different vine groups. The treate...

In this preliminary study, ultra-high-pressure liquid chromatography (UHPLC) coupled to quadrupole-time-of-flight mass spectrometry (QTOF) metabolomics followed by multivariate statistics was applied to discriminate nine extra-virgin olive oil (EVOO) cultivars according to their phenolic and sterolic fingerprints. The same approach was then used to...

Stomatal conductance is regulated by many factors such as air vapour pressure deficit (D), which can be the pivotal one affecting leaf gas exchange in species particularly sensitive to D such as C. avellana. The aim of this work was to evaluate stomatal sensibility to D and to determine correlations with hydraulics characteristics of leaves in thre...

Corylus avellana is a hard-to-root species, thus hazelnut cultivar propagation by stem cuttings is considered difficult. The rooting of cuttings is influenced by many exogenous and endogenous factors such as hormones, cutting quality, and environmental conditions. In particular, rooting success of soft wood cuttings could be enhanced by the applica...

Water relations are among the major factors affecting shoot growth and plant vegetative vigor. In many tree crops, dwarfing rootstocks regulate scion vegetative vigor by reducing plant hydraulic conductance. In Prunus spp. reduced xylem vessel size leads to reduced hydraulic conductance, but reduction of annual xylem tissue growth could have simila...

Important processes such as plant respiration, repair of damaged photosystems and carbohydrate translocation occurs during night. The lack of photosyntate translocation can influence photosynthetic efficiency of the leaves in the subsequent day. Night temperature can play and important role influencing the carbohydrate translocation. The aim of the...

Early leaf removal significantly alters the source-sink balance within grapevine shoots, leading to a reduction in fruit set. However, no research has previously examined the conditions controlling this process in terms of carbon allocation among major sink organs following defoliation. In this study, the impact of defoliation at bloom on the distr...

Correlation analysis between the actual number of florets (y) and the florets counted on the photographs (x); the equation is reported in the text.

Relationship between the LA per shoot (y) and shoot length (x) used for estimation of total LA.

Linear regression between the number of flowers counted on clusters sampled from guard vines and the number of flowers counted on pictures of the same clusters, shot in field conditions right before their sampling. Pictures shooting and clusters sampling was performed at full bloom (15th June), before application of defoliation on experimental vine...

Hazel belongs to the genus Corylus, where we find as economic interest to European Hazel (C. avellana L). Recommended cultivars for Italy are Tonda di Giffoni, Tonda Gentile delle Langhe (TGL) and Tonda Romana (TR), because of their nut quality, productivity, vigor and type of growth. Hazelnut is commonly propagated vegetatively by rooted suckers,...

Frequency of extreme drought events are expected to increase due to climate change. Perennials are increasingly exposed to recurrent drought during their life span. The aim of the present work was to study the effect of recurrent droughts on the behavior of Vitis vinifera under water stress. Sangiovese and Montepulciano vines were exposed to severe...

Olive harvesting often requires high hand labour, considering that workers, with long poles or hand held devices, aid trunk shaker due to low harvesting efficiency. Currently, fruit detachment force (FDF) and fruit fresh weight were used to predict harvesting efficiency, although during harvesting process, fruit is subjected to bending and twisting...

Most modern and traditional grape-growing regions are facing challenging times due to the unpredictability of weather conditions and warming trends. Innovative and sustainable tools such as seaweed-based biostimulants may play a key-role in the development of environment-friendly viticultural strategies to improve yields, biotic/abiotic stress tole...

The present study compares the physiological and cropping response of the new fungi-resistant grapevine Accession 72–096 (‘Sangiovese’ x ‘Bianca’ hybrid) against a susceptible ‘Sangiovese’ clone which was either fully (FS-SG) or partially sprayed (PS-SG). Data logged on Accession 72–096 indicate that while two early season sprays were enough to avo...

Over decades, the concept of grape quality has evolved emphasizing its multidisciplinary nature and that the same "desired quality" might correspond to even strikingly different compositional patterns. The review takes a long journey throughout the multiple factors impinging on grape quality, not excluding also sections devoted to table grapes. It...

Climate warming is causing an advance of the latest spring frosts and a consequent decrease of spring freeze risk during flowering. Cultivation areas of early blooming tree crops, such as almond, could be shifted pole-ward as consequence of global warming. On the other hand, warming winters and springs can cause an advance of the flowering period....

Sangiovese vines mechanically spur-pruned during dormancy in February were subjected to immediate or delayed (post bud-burst) manual finishing to test the potential of a ‘double-pruning’ approach to delay fruit sugar accumulation and limit yield. The treatments were applied in 2014, 2015 and 2016 at BBCH-0 as standard hand finishing on dormant buds...

Trunk shakers are among the most widespread machines for mechanical harvesting in intensive olive orchards (300–500 trees ha⁻¹). Harvesting effectiveness is an important issue for this sort of machine because, due to the heterogeneity of the tree canopy structure, vibration transmission is uneven and some branches vibrate poorly. The aim of the pre...

Leaf removal is a grapevine canopy management technique widely used to modify the source–sink balance and/or microclimate around berry clusters to optimize fruit composition. In general, the removal of basal leaves before flowering reduces fruit set, hence achieving looser clusters, and improves grape composition since yield is generally curtailed...

Hazelnut crop yields are closely related to the number of flowers produced on a plant. The number of flowers borne by each plant is the product of the number of shoots and number of flowers borne on each shoot. Shoot flowering is correlated with shoot vigour. The aim of the present work was to test the hypothesis that pruning can be used in hazelnu...

Ricerca in corilicoltura: strategie innovative L e prime evidenze della coltivazio-ne del nocciolo in Italia risalgono ai secoli V-IV a.C. e riguardano ritrovamenti archeologici in Campania (AA.VV., 1983). Le testimonianze successive della diffusione della coltura in Lazio, Sicilia e Piemonte sono numero-se, ma è solo nel XX secolo che questa assum...

Effects of flowering, fruiting, and fruit drop on leaf area, leaf nitrogen, probability of spur survival and return bloom were studied in an 11 year-old highly productive almond orchard. Six different spur categories (spurs with no fruit, spurs with flowers removed at full bloom, spurs with fruit removed at 14 days after full bloom (DAFB), spurs wi...

L’esperienza derivante dalle ricerche degli ultimi decenni in Italia indica le varietà Tonda di Giffoni, Tonda Romana e Tonda Gentile delle Langhe come riferimento per la corilicoltura italiana in termini di produttività e qualità. Il loro impiego può essere esteso anche in aree non tradizionalmente corilicole, previa l’attenta valutazione della lo...

Almond tree yield is a function of the number of flowers on a tree and the percentage of flowers that set fruit. Almonds are borne on spurs (short proleptic shoots that can have both leaves and flowers). Almond tree spur dynamics research has documented that previous year spur leaf area is a predictive parameter for year-to-year spur survival, spur...

Background Grapevine (Vitis vinifera L.) is an economically important crop with a wide geographical distribution, reflecting its ability to grow successfully in a range of climates. However, many vineyards are located in regions with seasonal drought, and these are often predicted to be global climate change hotspots. Climate change affects the ent...

The influence of pruning date on yield control and ripening rate of spur-pruned Sangiovese grapevines was investigated over two years (2013 and 2014). Winter pruning was applied on 1 or 4 Feb (mid dormancy); 1 or 5 March (late dormancy); 2 or 7 April (bud swell); 2 or 7 May (flowers closely pressed together); and 1 or 6 June (40 to 50% of flower ca...

Tree vigour is one of the most important issues in super-high density olive orchards (~1600 tree/ha). Tree vigour could be limited by horticultural practices such as pruning and fertilization but such practices have a limited effect and increase growing costs. The aim of this work was to test a new technique based on the application of a constricti...

Since machine introduction in the early 1970s, much work has been expended to adapt pruners to vine trellis and physiological requirements, especially regarding the higher bud load their non-selective cuts leave compared to manual trimming. While units have successfully met the former requirement, efforts to meet the latter have been hampered by a...

Manipulating or shifting annual grapevine growing cycle to offset limitations imposed by global warming is a must today, and delayed winter pruning is a tool to achieve it. However, no information is available about its physiological background, especially in relation to modifications in canopy phenology, demography and seasonal carbon budget. Mech...

Functionality of training systems different in size, shape and geometry are primarily a function of their ability to intercept and distribute light effectively within the canopy. In peach, methodologies for a rapid and reliable assessment of such features are still lacking. In this study we propose a systemic approach that as unique data entry requ...

Testing of new rootstocks for drought tolerance targets traditionally rain-fed districts where supplemental irrigation is more frequently needed due to the pressures of global warming. A seasonal evaluation of gas exchange and water-use efficiency (WUE) of cv. Sangiovese grafted to the new drought-tolerant genotype M4 in a dry-down trial against th...

Accelerated berry sugar accumulation resulting in wines of excessive alcohol concentration, sub-optimal colour and atypical flavour has become increasingly frequent in warm growing districts, a trend induced by factors that include global warming. The application of a film-forming antitranspirant may be an effective way of reducing early sugar accu...

Adventitious root formation in plant cuttings is influenced by many endogenous and environmental factors. Leaf photosynthesis during rooting of leafy cuttings in hard to root species can contribute to supply carbohydrates to the intensive metabolic processes related to adventious root formation. Light intensity during rooting is artificially kept l...

Photosynthetic performances and energy dissipation mechanisms were evaluated on the anisohydric cv. Sangiovese and on the isohydric cv. Montepulciano (Vitis vinifera L.) under conditions of multiple summer stresses. Potted vines of both cultivars were maintained at 90% and 40% of maximum water availability from fruit-set to veraison. One week befor...

Water saving under drought stress is assured by stomatal closure driven by active (ABA-mediated) and/or passive (hydraulic-mediated) mechanisms. There is currently no comprehensive model nor any general consensus about the actual contribution and relative importance of each of the above factors in modulating stomatal closure in planta. In the prese...

Vigorous peach scion cultivars, growing on graft-compatible rootstocks, exhibit differing amounts of vegetative growth, depending on the rootstock used. Recent research on the physiology of peach size-controlling rootstocks has indicated that the primary factor, that limits the vegetative growth, appears to be the hydraulic conductance characterist...

Almond spurs are known to be the primary bearing unit in almond tree and are subject to alternate bearing. Fruits are a strong sink in bearing spurs and can influence spur leaf growth. At the same time the percent of flowers that set fruit on a spur (spur relative fruit set) could be influenced by the competition among multiple flowers/fruits borne...

Stem or trunk girdling is a technique used in physiological studies and in horticultural practice for interrupting carbon flow through the phloem to other parts of the plant without influencing water flow in the xylem. Trunk girdling in peaches is practiced primarily to stimulate fruit growth but it also tends to decrease shoot vigour for a period...

Canopy management is one of the most important factors influencing yield and economic life of high density hedgerow olive orchards. Currently, the canopy volume is set mainly on the basis of size of over-head harvesting machines; this is a limit for natural growth of trees which have to be pruned hard once the allotted canopy size is reached. Thus,...