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Unidad de excelencia María de Maeztu CEX2019-000940-M Solar radiation entering a high-wire tomato greenhouse is mostly intercepted by the top of the crop canopy, while the role of lower leaves diminishes with age, turning them into sink organs rather than sources. Accordingly, the defoliation of basal leaves is a widely applied agronomic practice in high-wire greenhouse cultivation management. However, the recent increase in the application of supplemental light emitting diode (LED) lighting for high-density tomato production may affect the role of basal leaves, promoting their source role for fruit development and growth. The present research aims to explore the application of supplementary LED lighting on Solanum lycopersicum cv. Siranzo in the Mediterranean area during the cold season in combination with two regimes of basal defoliation. The defoliation factors consisted of the early removal of the leaves (R) right under the developing truss before the fruit turning stage and a non-removal (NR) during the entire cultivation cycle. The lighting factors consisted of an artificial LED lighting treatment with red and blue diodes for 16 h d−1 (h 8-00) with an intensity of 180 µmol s−1 m−2 (RB) and a control cultivated under natural light only (CK). The results demonstrated a great effect of the supplemental LED light, which increased the total yield (+118%), favoring fruit setting (+46%) and faster ripening (+60%) regardless of defoliation regimes, although the increased energy prices hinder the economic viability of the technology. Concerning fruit quality, defoliation significantly reduced the soluble solid content, while it increased the acidity when combined with natural light.

BACKGROUND: Texture is important in the preferences of apple consumers. Of the pre-harvest factors affecting fruit quality and especially texture, altitude and subsequent climatic conditions are crucial, determining differences in the physiological mechanisms of fruit growth, ripening stage and chemical composition, as demonstrated by several studies. This work applies a detailed sensory-instrumental protocol developed in a previous paper to investigate the impact of altitude, time of harvest and their cross-effect on sensory characteristics of apple, with a focus on texture. RESULTS: Sensory differences were found in relation to altitude, although the profile results were mainly affected by the time of harvest. Fruit from lower altitude was described as juicier, crunchier and sweeter than samples from higher altitude, which were floury, sourer and more astringent. Texture performance, soluble solids content and titratable acidity corroborated this sensory description. Moreover, anatomical data showed that fruit from lower altitude had a larger volume, a higher number of cells and a higher percentage of intercellular spaces. CONCLUSION: We demonstrated that differences between fruit from various altitudes can be perceived through human senses, and that the proposed sensory–instrumental tool can be used to describe such differences. This study brings more understanding about the impact of altitude and time of harvest on apple sensory properties. This work could support apple producers, from semi-mountainous regions (Alps, Tyrol, etc.), in advertising and valorising their products with their specific characteristics in a more efficient manner. © 2017 Society of Chemical Industry.

To cope with increasing water scarcity, breeding programs targeting for more efficient crop water use are crucial. This requires comprehensive knowledge of plant responses to drought, including the regulation of water status (by stomatal closure) and water - use efficiency (the ratio of carbon gain to water use). These questions have been scarcely studied in fruit trees, yet are of major economic importance. A main limitation results from the lack of high throughput techniques to characterize the physiological responses of hundreds of trees in the field as required to perform genetic analyses. We screened the diversity of European apple tree responses to drought, by unique combination of hight hroughput and in planta measurements applied on two core - collections in Montpellier (France) and Bologna (Italy), respectively. A progressive soil water deficit was ensured and continuously monitored in both orchards, through summer irrigation withholding. In the whole collections (>250 varieties), a semi-empirical index (IPL index), computed from chlorophyll fluorescence measurements, was used as an indicator of leaf photosynthesis, whereas the variability of stomatal regulation and canopy structure was characterized by airborne imagery. The validity of high-throughput indices was assessed through fine measurements of water potential, stomatal conductance and photosynthesis on 6 varieties common to both collections. A large variability of IPL index was observed, with highly significant effects of the genotype and watering scenario (well-watered vs water stress). A genome wide association study (GWAS) was undertaken to identify the genomic regions controlling the variations detected. In parallel, the effect of interaction between Genotype and Environment (GxE) was dissected to highlight contrasted strategies of water use under drought across the varieties studied.

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Riassunto La ricerca ha lo scopo di valutare l’effetto della riduzione degli apporti irrigui sulle performance fisiologiche ed agronomiche della cultivar Abate Fetél innestata sui 4 portinnesti più comunemente utilizzati nella Valle del Po. La prova è stata effettuata presso l’azienda agricola dimostrativa “Fondazione per l’Agricoltura Fratelli Navarra” sita in Ferrara, Emilia Romagna, mettendo a confronto quattro differenti portinnesti e densità di impianto: MC, Sydo, Adams ed MH. Le 4 combinazioni sono state sottoposte ai seguenti 4 livelli di irrigazione decrescenti:100%, 50%, 25% RDI-IRRINET, test asciutto. L’irrigazione è stata gestita seguendo un bilancio idrico secondo il modello IRRINET fornito dal Consorzio per il Canale Emiliano Romagnolo (CER), che tiene conto del regime di Deficit di irrigazione controllato (RDI). Il bilancio idrico del modello IRRINET ha confermato la propria validità nella stima dell’umidità del terreno, avendo registrato una buona corrispondenza con i valori di umidità misurati dai sensori disposti nella prova. I dati produttivi medi del biennio, relativi alla fase di piena produzione, inoltre, hanno evidenziato che il cotogno C, abbinato a forme di allevamento e impianti superfitti (12.000 piante/ha), deprime la pezzatura in misura significativa rispetto agli altri portinnesti, con un conseguente calo di prodotto commerciale. Summary This three-year trial is carried out at the Demonstration Farm of the “Fondazione per l'Agricoltura Fratelli Navarra” located near Ferrara, Emilia-Romagna. On Abbé Fétel grafted on 4 of the most currently used rootstocks in the Po Valley (MC, Sydo, Adams and MH) contrasting irrigation volumes are assessed, in each phenological stage and scion/rootstock combination, to determine the minimum irrigation level at which plants are not exposed to damaging water stress conditions. The different volumes were determined as fractions of the IRRINET daily recommendation for Regulated Deficit Irrigation (RDI) in this orchard, and various agronomic parameters were determined. The IRRINET model proved suited to predict soil water content; decreasing irrigation volumes determined decreasing % of marketable yields, and diminishing fruit size, while total yields were not decreasing (for some rootstocks) between 100 and 50% IRRINET. MC performance was generally lower than for the other rootstocks, revealing the limits of its quite low vigour.

The effect of shading (i.e. reduction of sunlight availability) on fruit growth physiology has been widely studied in apple (Malus domestica Borkh.), but little knowledge exist about fruit growth responses to changes in the light spectrum. The aim of the present research was to study the effect of use of colored nets with differential sunlight transmission in the blue (B, 400-500 nm), red (R, 600-700 nm) and far-red (FR, 700-800 nm) spectra on apple fruit growth and physiological associated responses. Three year old ’Fuji’ apple trees were covered with 40% photo-selective blue and red shade nets, 40% neutral grey shade net, and 20% neutral white net as control. Red and blue net reduced in the same proportion (27%) the photosynthetically active radiation with respect to control. However, blue net increased by 30% and reduced by 10% the B:R and R:FR the light relations, respectively. Maximal fruit growth rate under blue and grey nets was 15-20% greater than control. Fruit weight under blue net was 17% greater than control, but no significant differences in fruit weight were found among red net and control. Leaf photosynthesis and total leaf area under blue net were 28% and 30% higher than control, respectively; with ensuing positive effect on tree net C assimilation rate and total dry matter production. Results suggest that shifting the B, R, and FR light composition with photo-selective nets could be a useful tool to manipulate the photosynthetic and morphogenetic process regulating the carbohydrate availability for apple fruit growth. El efecto del sombreado (i.e. reducción de la cantidad de luz solar) sobre la fisiología de crecimiento de fruto ha sido ampliamente estudiado en manzano (Malus domestica Borkh.), pero existe poco conocimiento sobre respuestas de crecimiento del fruto a cambios en el espectro de la luz. El objetivo de la presente investigación fue estudiar el efecto del uso de mallas de color con transmisión diferencial de la luz en el espectro azul (B, 400-500 nm), rojo (R, 600-700 nm) y rojo lejano (FR, 700-800 nm) sobre crecimiento de fruto y respuestas fisiológicas asociadas en manzano. Árboles de manzano ’Fuji’ de 3 años de edad fueron cubiertos con mallas foto-selectivas azul y roja al 40%, y neutras gris al 40% y blanca al 20% (control). Las mallas azul y roja redujeron en la misma proporción (27%) la radiación fotosintéticamente activa respecto al control. Sin embargo, la malla azul incrementó en 30% y redujo en 10% las relaciones de luz B:R y R:FR, respectivamente. La tasa máxima de crecimiento de fruto bajo las mallas azul y gris fue 1520% mayor que el control. El peso de fruto bajo la malla azul fue 17% mayor que el control, pero no se encontraron diferencias significativas de peso de fruto entre la malla roja y el control. La fotosíntesis de la hoja y área foliar total bajo la malla azul fueron 28% y 30% mas altas que el control, respectivamente; con un consiguiente efecto positivo sobre la asimilación neta de C por el árbol y producción de materia seca total. Los resultados sugieren que cambiar la composición de luz B, R, y FR a través de mallas foto-selectivas podría ser una herramienta útil para manipular los procesos fotosintéticos y morfo-genéticos que regulan la disponibilidad de carbohidratos para el crecimiento de fruto en manzano.

The effect of shading (i.e. reduction of sunlight availability) on fruit growth physiology has been widely studied in apple (Malus domestica Borkh.), but little knowledge exist about fruit growth responses to changes in the light spectrum. The aim of the present research was to study the effect of use of colored nets with differential sunlight transmission in the blue (B, 400-500 nm), red (R, 600-700 nm) and far-red (FR, 700-800 nm) spectra on apple fruit growth and physiological associated responses. Three year old ‘Fuji’ apple trees were covered with 40% photo-selective blue and red shade nets, 40% neutral grey shade net, and 20% neutral white net as control. Red and blue net reduced in the same proportion (27%) the photosynthetically active radiation with respect to control. However, blue net increased by 30% and reduced by 10% the B:R and R:FR the light relations, respectively. Maximal fruit growth rate under blue and grey nets was 15-20% greater than control. Fruit weight under blue net was 17% greater than control, but no significant differences in fruit weight were found among red net and control. Leaf photosynthesis and total leaf area under blue net were 28% and 30% higher than control, respectively; with ensuing positive effect on tree net C assimilation rate and total dry matter production. Results suggest that shifting the B, R, and FR light composition with photo-selective nets could be a useful tool to manipulate the photosynthetic and morphogenetic process regulating the carbohydrate availability for apple fruit growth.

Despite irrigation being one of the most powerful tools to increase yields and maintaining profitability in fruit production, most farm operations are not following sound irrigation management tools, although there are many available to them, even through the Internet. As societal pressure is on agriculture to reduce its use of the water resource, ecophysiological studies are elucidating the mechanisms underpinning the interplay between leaf, fruit and stem water relations, and how these affect fruit growth. Daily variations in water potentials of these organs are involved (in different manners for different species) in the process of fruit growth but more interestingly, the possibility arises of manipulating the gradients between these potentials that occur during the day, enhancing the fruit's capacity to attract dry matter and water, that are needed to grow, while saving water.

There has been very little literature on the spatial variability of fruit production in horticulture crops published to date. Most of the existing literature refers to data collected at picking time. Crop load data taken prior to hand thinning and prior to harvest were collected in 3 blocks of a commercial apple (Malus domestica Borkh.) orchard in the Po valley (Ferrara, Italy). The purpose of the survey was to characterize the within field variability of crop load, using spatial statistics, and assess the effectiveness of the hand-thinning treatment to eliminate this variability. Crop load estimations were taken at 156 sites pre and post hand-thinning over a defined distance (0.8 m) and the data used to model a variogram and associated spatial analysis. Variation in the spatial distribution of the fruit load prior to the hand-thinning was observed, indicating a possibility to spatially differentially manage the orchard. No spatial variation in fruit number was observed prior to harvest (post thinning), indicating that thinning had removed the previously observed spatial variation in crop load. However, the spatial variation observed prior to thinning may indicate that a differential crop load management strategy may be optimal for maximizing quality in the orchard.

Nel pesco, come in altre specie, la crescita di un frutto risulta dipendente dalla quantità di risorse a disposizione. Quando queste non sono limitanti, le sue caratteristiche genetiche ne definiscono la massima crescita potenziale. In frutteti commerciali i frutti si sviluppano in condizioni di competizione ed il raggiungimento di una buona qualità del prodotto alla raccolta può essere limitato proprio dalle risorse disponibili per ogni singolo frutto. In questa prova, 5 diversi carichi di frutti sono stati impostati, per due anni consecutivi, su 20 piante di nettarina ‘Stark RedGold’. Per ogni pianta, la crescita diametrale dei frutti è stata seguita durante la stagione, mentre alla raccolta sono stati determinati produttività e peso medio dei frutti. Nel secondo anno, l’andamento giornaliero di intercettazione luminosa e di assimilazione per intera chioma sono state determinate su due piante di riferimento appartenenti rispettivamente ai trattamenti con più basso e più alto carico di frutti. Inoltre, l’intercettazione luminosa totale di ogni pianta in prova è stata determinata in corrispondenza del mezzogiorno solare. I dati di intercettazione e di assimilazione netta durante la giornata sono risultati linearmente correlati (R2=0.70), confermando come la quantità di carbonio potenzialmente fissato da un albero sia direttamente proporzionale alla quantità di luce che esso è in grado di intercettare. Inoltre, l’energia disponibile per ogni frutto, calcolata dal rapporto tra l’intercettazione totale dell’albero ed il suo numero di frutti, ha mostrato una relazione curvilinea positiva con il peso medio del frutto alla raccolta. Tale relazione diventa saturante a partire da 70-100 mol di fotoni frutto-1 s-1 . Questo intervallo di valori può quindi essere considerato una soglia al di sotto della quale l’accrescimento dei frutti è limitato dagli assimilati disponibili (source limited); mentre al di sopra di questa, il frutto è limitato dalle sue potenzialità genetiche (sink limited).

The relative contributions of xylem, phloem and transpiration to fruit growth and the daily patterns of their flows have been determined in peach during the two stages of rapid diameter increase by precise and continuous monitoring of fruit diameter variations. Xylem, phloem and transpiration contributions to growth were quantified by comparing the diurnal patterns of diameter change of fruits which were subsequently girdled and detached. Xylem supports 70% and phloem 30% of peach growth , while transpiration represents about 60% of daily total inflows. These figures and their diurnal patterns were comparable among years, stages and cultivars. The xylem was functional both at stage I and III, while fruit transpiration was high and strictly dependent on environmental conditions, causing periods of fruit shrinkage. Phloem imports were correlated to fruit shrinkage and appear to facilitate subsequent fruit enlargement. Peach displays a growth mechanism which can be explained on the basis of passive unloading of photoassimilates from the phloem. A pivotal role is played by the large amount of water flowing from the tree to the fruit and from the fruit to the atmosphere.

The relative contributions of xylem, phloem and transpiration to fruit growth and the daily patterns of their flows have been determined in peach during the two stages of rapid diameter increase by precise and continuous monitoring of fruit diameter variations. Xylem, phloem and transpiration contributions to growth were quantified by comparing the diurnal patterns of diameter change of fruits which were subsequently girdled and detached. Xylem supports 70% and phloem 30% of peach growth , while transpiration represents about 60% of daily total inflows. These figures and their diurnal patterns were comparable among years, stages and cultivars. The xylem was functional both at stage I and III, while fruit transpiration was high and strictly dependent on environmental conditions, causing periods of fruit shrinkage. Phloem imports were correlated to fruit shrinkage and appear to facilitate subsequent fruit enlargement. Peach displays a growth mechanism which can be explained on the basis of passive unloading of photoassimilates from the phloem. A pivotal role is played by the large amount of water flowing from the tree to the fruit and from the fruit to the atmosphere.

Net photosynthesis, at the base of plant productivity, increases with irradiance till a saturating point. All the extra absorbed energy may be considered excessive and can emphasize the photoprotective and photoinactivation mechanisms with a consequent decrease of plant dry matter accumulation. Several areas in which peach is commonly grown the excessive light is often associate with water limitation that can in turn exacerbate the loss due to photoinhibition increase and net photosynthesis reduction. In this study the ameliorative consequences of light reduction of about 40% trough a neutral shading net were pointed out. Light reduction, associate with temperature mitigation did not affect leaf net photosynthesis but it reduced water consumption and the amount of inactive photosynthetic complexes to be repaired at expense of dry matter accumulation. Under the shading net the entity of the photoprotective mechanisms decreased since leaves were less exposed to light excess. The consequence of this favourable state was probably the increase of dry matter accumulation, including fruit production.

La produttività degli alberi da frutto è linearmente legata alla quantità di luce intercettata; tuttavia tale relazione diviene meno stretta quando il livello di luce intercettata supera il 50% della radiazione disponibile. In questo lavoro vengono presentati i risultati di studi riguardanti la gestione della radiazione incidente da parte di piante di pesco, attraverso misure di intercettazione luminosa e scambio gassoso su chiome intere, combinate con rilievi di scambio gassoso e fluorescenza della clorofilla a livello di singola foglia. La prova è stata condotta su alberi appartenenti ad un frutteto sperimentale denominato “Pescheto Asimmetrico”, dove diverse combinazioni di orientamento dei filari ed inclinazione delle chiome hanno permesso la sussistenza di tre differenti profili radiativi (C, E, O) nelle medesime condizioni di campo. I livelli di fotosintesi netta (NCU) e traspirazione (TRWP) della chioma misurati sulle piante di controllo (C) sono risultati simili a quelli della tesi O, sebbene quest’ultima abbia intercettato la quantità più alta di luce, soprattutto al mattino. Gli alberi sottoposti ad alta irradianza al pomeriggio (E) hanno mostrato i valori di NCU e TRWP più alti, mantenendo un efficienza d’uso dell’ acqua (WUE) simile alle rimanenti tesi poste a confronto. Nei peschi della tesi O il fotodanno è stato più alto che in C e E, rispettivamente del 29% e 8%. L’analisi della ripartizione dell’energia assorbita ha evidenziato che la dissipazione termica (non photochemical quenching, NPQ) è risultata il meccanismo fotoprotettivo principale per la dissipazione degli eccessi luminosi, anche se alle radiazioni medio-basse sembrerebbe limitata dalla bassa concentrazione di H+ nel lumen dei tilaciodi. I trasporti elettronici alternativi (NC) hanno mostrato una maggiore efficienza fotoprotettiva a livelli luminosi medio-bassi facilitando, inoltre, l’instaurarsi di un pH ottimale per la piena attivazione del NPQ. I risultati ottenuti suggeriscono che in molti casi, specie nelle zone con alti livelli luminosi e bassa disponibilità idrica, la radiazione luminosa è eccessiva e può causare limitazioni termiche e stomatiche in aggiunta all’aumento del fotodanno, la cui riparazione richiede energia in forma di assimilati sottratti all’accumulo di sostanza secca ed alla produttività.

L’analisi spaziale applicata ad appezzamenti frutticoli è un'innovazione tecnologica della frutticoltura di precisione che ha il principale scopo di monitorare le informazioni che il sistema frutteto può restituire in ogni momento della stagione colturale al fine di meglio programmare gli interventi e ridurre i costi. Essa sfrutta la sinergia di tecniche di analisi geostatistiche e di rilievo puntuale dei dati che consentono di implementare strategie di gestione a livello di singolo appezzamento. Le possibilità applicative sono svariate, tra cui l’opportunità di guidare e valutare in tempo reale l’effetto di singole pratiche colturali come il diradamento dei frutti, oppure l'ottimizzazione della gestione del frutteto nel suo insieme. Questo articolo descrive alcuni dei parametri e delle tecniche utilizzate nell’analisi del dato e propone un esempio applicativo in campo melicolo per la gestione del diradamento.

Photoselective nets were used to examine apple shoot physiology during dormancy and budbreak. Two trials were conducted: one in the field and one in controlled conditions. In the first, three colored nets (red, blue, and white, shading 20%) covered sections of single trees, leaving an empty portion as control, from December to April. The white net increased canopy air temperature compared with the blue one. Differences were found in carbohydrate seasonal patterns; however, it appeared that soil temperature had higher impacts on sugar movement in the trees. No differences were found in bud phenology. In the second trial, cuttings were placed in boxes constructed with the same-colored nets and monitored from the end of February to April. Results showed differences in phenology and carbohydrate translocation. The white box hastened bloom and its cuttings had higher amounts of carbohydrates at the end of the trial. On the contrary, the blue box delayed bloom while resources were still being consumed and its cuttings had the lowest amounts of reserves at the end of the trial. These results add new insights on apple physiology under different light spectra and commercial applications should not be excluded for improving crop management.

Irrigation with secondary treated wastewater (STW) as a support to traditional irrigation management is becoming a necessary alternative to addressing issues of water shortage and fertilizer saving. The application of STW on young potted plants of Prunus persica (L.); cv: Big Top, grafted on GF 677, was studied outdoors on two consecutive seasons, during which three different irrigation treatments were compared: 1) irrigation with STW; 2) irrigation with tap water with the addition of mineral fertilizer (TW + MF) and 3) irrigation with tap water (TW). To assess the effects of the different irrigation treatments, tree nutritional status, shoot growth, Stem Cross Sectional Area (SCSA), Trunk Cross Sectional Area (TCSA), leaf gas exchanges, plant water status, fruit growth, fruit yield and quality were monitored during both seasons. Tree nutritional status, vegetative growth, TCSA, cumulative plant photosynthesis, fruit growth and yield were positively influenced by STW irrigation, compared to TW. TW + MF trees showed the highest vegetative growth and vegetative/reproductive ratio. This induced a rise in their water use and a consequent decrease in stem water potential, indicating the onset of water stress conditions. Results indicated that there was no negative effect of STW application on any of the monitored parameters. STW partially improved the plant physiological, nutritional and productive performances due to its intrinsic fertilizing effect. These results encourage further studies on the possibilities to directly use STW as an alternative source for irrigating and fertigating fruit crops even in open field conditions.

The objective of this 2-year study (2017, 2019) was to evaluate the influence of photoselective nets on apple fruit growth, focusing on the initial fruit growth stages of “Pink Lady”. Trees were subjected to four photoselective nets (Blue, Red, White and Yellow) and a standard black one (serving as Control), resulting in 5 light environments (LE), all shading at 20%. From 20 to 90 DAFB, 32 fruit and extension shoots, for each LE, were measured for a total of 11 times during the season. For each LE, fruit gauges were also installed to monitor fruit daily growth parameters, from 50 to 90 DAFB. At harvest, all fruit from each light environment were weighed and quality parameters were measured on 40 fruit per treatment. For each year, correlations were made to test the influence of LEs on final fruit weight and quality, and the impact that extension shoot growth had on fruit growth. In both years, white and control nets led to the production of fruits with higher weight compared to the other treatments (blue, red and yellow nets). In 2019, LEs did not appear to influence the relationship between shoot and fruit growth, probably due to the higher crop load and the massive pruning carried out the previous year. The higher vegetative outburst in this year might have unbalanced resources towards the shoots, than towards the fruit. Results show how weather and orchard management heavily influenced the trees responses. Yet, the consistent findings of final fruit weight, for both years, indicate that different wavelengths influence fruit and shoot behavior, even at early phenological stages. Hence, growers searching for bigger fruit should refer to white and black nets. Further studies approaching this technology can help improve apple production management and knowledge of the use of photoselective nets.

Capitolo di libro, sprovvisto di abstract. Dal sito dell'editore: By adopting precise management techniques, growers can reduce the environmental impact of fruit growing, without sacrificing quality and yields, while maintaining income. This chapter discusses how improvements in sustainable peach production can be achieved by an interaction among quite varied disciplines. The chapter describes the importance of vascular flows to peach fruit growth and focuses on the significance of photosynthesis as the engine of productivity in peach production. The chapter considers the adoption of precision fruit growing, and provides a case study. Finally, the chapter looks ahead to future research trends in this area.

Leaf photosynthetic performance of a new red-skinned inter-specific hybrid pear variety called ‘PremP009’ (PIQA® BOO®) is presently unknown and therefore was compared to the Asian pear variety ‘Hosui’. The seasonal growth patterns and the final dry matter accumulation of all tree components were also investigated for both genotypes in their first year of growth after grafting. Leaf gas exchange and tree growth comparisons were assessed using an innovative grafted plant system, which involved a bi-axis tree with the presence of combinations of identical or mixed (one of each genotype) ‘PremP009’ and ‘Hosui’ scion genotypes grafted onto a single clonal rootstock (‘Buerre Hardy’ BA29). This experimental grafted plant system allowed a technique for comparing leaf photosynthesis of two scion genotypes on the same root system, thereby avoiding between-plant differences in plant water relations. ‘PremP009’ had higher leaf photosynthesis and higher leaf mass compared with ‘Hosui.’ However, by the end of the first year of growth, primary shoots of ‘PremP009’ were shorter with fewer nodes, corresponding to less dry weight gain in primary shoot leaves and stems. This vegetative behavior of ‘PremP009’ is likely a response to the smaller individual leaf area in the early season affecting light capture that greatly limits dry matter accumulation of young trees. HIGHLIGHTS - The bi-axis grafting technique never showed before in a scientific paper presents a strategic systemfor a comparative study of red/green leaf photosynthetic performance and related dry matter partitioning.

The cultivation of Actinidia deliciosa requires high amounts of water and innovative approaches for optimizing its irrigation scheduling are needed. This paper tests the possibility to improve the kiwi vine physiological performances by changing the timing of water supply during the day. Two irrigation treatments were applied in a 'Hayward' commercial orchard, both providing 100% of crop evapotranspiration (ETc) but differing for the time of the day when irrigation was applied: early in the morning (M) or at midday/early afternoon (A). The daily patterns of soil water content, stem, fruit-bearing branch, leaf and fruit water potentials, sap flow along the branch, leaf gas exchanges, fruit growth, phloem, xylem and transpiration flows to/from the fruit were monitored at different times during the season: 6, 9, 11 and 18 weeks after full bloom (WAFB). In most dates A irrigation increased trunk, stem and leaf water potentials, as well as leaf gas exchanges, during the afternoon, i.e., when the highest air vapor pressure deficits (VPDs) were recorded. As fruit pressure potential was unaffected by the treatments, fruit from "A" irrigated vines took advantage of a higher stem-to-fruit water potential gradient. In response to this, at 11 WAFB, when the highest VPDs were recorded, "A" fruit experienced a higher xylem flow during the afternoon. Fruit growth was slightly improved at this time of the day but did not show any significant difference between treatments on a cumulative daily basis, probably due to the amount of water supplied (100% ETc). This work shows how the hour of irrigation can affect the vine physiological performances. Although further investigation is needed, supplying water in the afternoon, when environmental conditions are more stressing, has the potential of improving kiwifruit vine water status, leaf gas exchanges, and xylem flows to the fruit, and this may provide a new approach at increasing water use efficiency in this crop. (C) 2015 Elsevier B.V. All rights reserved.

L'agricoltura richiede innovazioni per incrementare le rese produttive in termini quantitativi e qualitativi, ma anche per aumentare l'efficienza nella gestione delle risorse. E' necessario ridurre l'impatto ambientale ed i costi di produzione, in un contesto di cambiamenti climatici e di globalizzazione dei mercati. Il libro illustra le tecnologie e le strategie gestionali dell'agricoltura di precisione applicate alle produzioni vegetali, quale insostituibile supporto per affrontare queste sfide, adattando la gestione agronomica alla variabilità nello spazio e nel tempo dei sistemi colturali e del suolo. Viene fornito un quadro aggiornato dei metodi per rilevare, analizzare e gestire la variabilità spaziale e temporale, sfruttando le tecnologie esistenti: dal telerilevamento ai sistemi di mappatura delle rese, dai droni alle applicazioni a rateo variabile.

In drought-stressed apple, leaf area decrease and stem growth cessation increase are key determinants of drought avoidance. Both the genotype and its possible phenotypic plasticity contribute to the variability of responses. Under soil water restriction, plant growth is impaired by the indirect negative impact on plant carbon balance of stomata closure and hydraulic failure. The relative contributions of these two phenomena have been scarcely explored in trees under different drought-stress intensities, and even less work is published which accounts for genetic variability and phenotypic plasticity. Working on 21 apple genotypes from the same progeny, we assessed the effects of two consecutive periods of soil drought, moderate and severe, on growth and functional patterns of leaf and stem. Leaf area decreased while temporary stem growth cessation increased under drought with strong variations depending on the genotype. These results suggested that both reduction of transpiring leaf area and leaf organogenesis are key determinants for drought avoidance in the apple. Results also confirmed the pivotal role of stomatal conductance (g s) in maintaining percent loss of conductivity of the stem xylem (PLC) under values for runaway embolism (ca. 14 % under severe drought). The sorting of genotypes according to their morphological response to drought showed that genotypes with high reduction of growth were characterized by similar g s but lower PLC than genotypes with medium and low reduction of growth. This suggests that for a given level of stomatal closure the drought-related reduction of leaf area could also limit the progression of cavitation in stem xylem. As a whole, the variability of morphological responses of apple genotypes to contrasted drought conditions indicated that both genetic variability and phenotypic plasticity are involved in the range of iso-anisohydry documented for this species.

L'agricoltura richiede innovazioni per incrementare le rese produttive in termini quantitativi e qualitativi, ma anche per aumentare l'efficienza nella gestione delle risorse. E' necessario ridurre l'impatto ambientale ed i costi di produzione, in un contesto di cambiamenti climatici e di globalizzazione dei mercati. Il libro illustra le tecnologie e le strategie gestionali dell'agricoltura di precisione applicate alle produzioni vegetali, quale insostituibile supporto per affrontare queste sfide, adattando la gestione agronomica alla variabilità nello spazio e nel tempo dei sistemi colturali e del suolo. Viene fornito un quadro aggiornato dei metodi per rilevare, analizzare e gestire la variabilità spaziale e temporale, sfruttando le tecnologie esistenti: dal telerilevamento ai sistemi di mappatura delle rese, dai droni alle applicazioni a rateo variabile.

The detection of leaf functionality is of pivotal importance for plant scientists from both theoretical and practical point of view. Leaves are the sources of dry matter and food, and they sequester CO2 as well. Under the perspective of climate change and primary resource scarcity (i.e. water, fertilizers and soil), assessing leaf photo-assimilation in a rapid but comprehensive way can be helpful for understanding plant behavior under different environmental conditions and for managing the agricultural practices properly. Several approaches have been proposed for this goal, however, some of them resulted very efficient but little reliable. On the other hand, the high reliability and exhaustive information of some models used for estimating net photosynthesis are at the expense of time and ease of measurement. The present study employs a multivariate statistical approach to assess a model aiming at estimating leaf photo-assimilation performance, using few and easy-to-measure variables. The model, parameterized for apple and pear and subjected to internal and external cross validation, involves chlorophyll fluorescence, carboxylative activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCo), air and leaf temperature. Results prove that this is a fair-predictive model allowing reliable variable assessment. The dependent variable, called IPL index, was found strongly and linearly correlated to net photosynthesis. IPL and the model behind it seem to be (1) reliable, (2) easy and fast to measure and (3) usable in vivo and in the field for such cases where high amount of data is required (e.g. precision agriculture and phenotyping studies).