1,721,119 research outputs found
Assessment of the seasonal pattern of burr and nut growth in a chestnut ‘Marrone-type’ cultivar
Full text linkSeasonal patterns of burr and nut growth were measured in sweet chestnut trees (C. sativa
Mill.) of the cultivar ‘Marrone di Castel del Rio’. Burr and nut growth expressed as diameter, fresh and
dry weight, and dry matter were assessed from mid of June to mid of October. Results evidenced that burr mainly grows in the initial period of the season, while the nut had a rapid growth in the last part of
the season (i.e., beginning of September). Dry matter of burrs started decreasing when its accumulation
in the nuts was increasing. Burrs with the highest number of nuts (three), experienced a limited nut
growth compared to burrs with two or one nuts per burr, but only at the beginning of nut filling phase.
Lateral nut evidenced a higher growth in weight (fresh and dry) in the first part of the season with occasionally
reduced dry matter compared to central nuts. The burr diameter had a strong positive relationship
with the internal nut diameter and with the total nut weight
Precision Management of Fruit Trees
Full text linkThe aim of the Special Issue “Precision Management of Fruit Trees” was to collect new insights to support the adoption of advanced, efficient, and sustainable management techniques in the fruit production sector. Indeed, this is an opportunity offered by the technological innovations adopted using new-generation sensors and implemented through precise management operations. This Special Issue contains 11 scientific articles contributing to our knowledge on the precision management of fruit trees, indicating the high activity of this sector and possibly leading to the application of new techniques/protocols to overcome global and rapidly changing environmental issues.
Scalisi et al. [1], in their study, aimed to (i) determine the reliability of a portable Bluetooth colour meter for fruit colour measurements; (ii) characterise the changes in quantitative skin colour attributes in a nectarine cultivar in response to time from harvest; and (iii) determine the influence of row orientation and training system on nectarine skin colour. Overall, the device proved reliable for fruit colour detection. The results of this study highlight the potential of one of the measured parameters as a quantitative index to monitor ripening prior to harvest in nectarines.
Remote sensing techniques based on images acquired from unmanned aerial vehicles (UAVs) could represent an effective tool to speed up the data acquisition process in phenotyping trials and, consequently, to reduce the time and cost of the field work. Caruso et al. [2] confirmed the ability of a UAV equipped with RGB-NIR cameras to highlight differences in geometrical and spectral canopy characteristics between eight olive cultivars planted at different planting distances in a hedgerow olive orchard.
Tree densities have increased greatly in olive orchards over the last few decades. Ladux et al. [3], in their study, found that the leaf area index (LAI) of neighbouring trees modifies the light quality environment prior to a tree being directly shaded, as well as the morphological responses of olive cultivars to changes in light quality. The results suggested that cultivar differences in response to light quality may be relevant for understanding adaptation to dense orchards and identifying cultivars best suited to them.
Saha et al. [4] found that monitoring plant vegetative growth can provide the basis for precise crop management. In this study, a 2D light detection and ranging (LiDAR) laser scanner, mounted on a linear conveyor, was used to acquire multi-temporal, three-dimensional (3D) data from strawberry plants. The results contributed to building up an approach for estimating plant geometrical features, particularly strawberry canopy volume profile based on LiDAR point cloud for tracking plant growth.
Carella et al. [5] studied the physiological and productive behaviour of different olive cultivars grown under a high-density hedgerow system and compared their fruiting and branch architecture features to determine the possibility to use ‘Calatina’ olive trees for intensive plantings, as a local alternative to the international reference ‘Arbequina’. The study indicated that ‘Calatina’ is more efficient in terms of yield and harvesting than ‘Arbequina’. This qualifies ‘Calatina’ as a superior, yield-efficient olive cultivar suitable for intensive hedgerow plantings to be harvested with straddle or side-by-side trunk shaker machines.
Sirgedaitė-Šėžienė et al. [6] used ‘Rubin’ apple trees grafted on dwarfing P60 rootstocks to determine the impact of canopy training treatments as a stress factor on metabolic response to obtain key information on how to improve physiological behaviour and the management of growth and development of apple trees. The results indicated that all applied canopy training treatments significantly increased the total phenol and total starch contents in apple tree leaves.
Scalisi et al. [7] in their work aimed to derive a new fruit skin colour attribute—namely, a Colour Development Index (CDI), ranging from 0 to 1, that intuitively increases as fruit becomes redder—to assess colour development in peach and nectarine fruit skin. The study found that the CDI can serve as a standardised and objective skin colour index for peaches and nectarines.
Čirjak et al. [8] summarize the automatic methods (image analysis systems, smart traps, sensors, decision support systems, etc.) used to monitor the major pest in apple production (Cydia pomonella L.) and other important apple pests and fruit flies to improve sustainable pest management under frequently changing climatic conditions.
Pisciotta et al. [9] released a review underlying the opportunities offered by the recently developed table-grape soil-less cultivation systems; this is an up-to-date examination of the latest experimental and applied findings of the sector’s research activities. A special emphasis is given to the evolution of the applied technical solutions, varietal choice, and environmental conditions for the aims of table-grape soil-less cultivation.
Borgogno-Mondino et al. [10] evaluated a promising alternative offered by Copernicus Sentinel 2 data (S2) to midday stem water potential for monitoring the water status of pomegranate plants and for addressing irrigation management. Despite limited ground observations, the results showed the promising capability of spectral indices (NDVI, NDRE, and NDWI) and S2 bands in estimating Ψstem readings.
Boini et al. [11], in their study, used shading nets to lower irrigation requirements and make apple growing more sustainable. The encouraging results showed a comparable yield and fruit quality saving 50% of irrigation water under a classic anti-hail system compared to the control treatment
Precision Management of Fruit Trees
No full textHorticulturae is an international, peer-reviewed, open access journal published monthly online by MDP
Orchard floor management affects tree functionality, productivity and water consumption of a late ripening peach orchard under semi-arid conditions
Full text linkSemi-arid conditions are favorable for the cultivation of late ripening peach cultivars; however, seasonal water scarcity and reduction in soil biological fertility, heightened by improper soil management, are jeopardizing this important sector. In the present two-year study, four soil managements were compared on a late ripening peach orchard: (i) completely tilled (control); (ii) mulched with reusable reflective plastic film; (iii) mulching with a Leguminosae cover-crop flattened after peach fruit set; (iv) completely tilled, supplying the water volumes of the plastic mulched treatment, supposed to be lower than the control. Comparison was performed for soil features, water use, tree functionality, fruit growth, fruit quality, yield and water productivity. Even receiving about 50% of the regular irrigation, reusable reflective mulching reduced water loss and soil carbon over mineralization, not affecting (sometimes increasing) net carbon assimilation, yield, and fruit size and increasing water productivity. The flattening technique should be refined in the last part of the season as in hot and dry areas with clay soils and low organic matter, soil cracking increased water evaporation predisposing the orchard at water stress. The development and implementation of appropriate soil management strategies could be pivotal for making peach production economically and environmentally sustainable
Apple responses to fruit sunburn in Italy
No full textSunburn is a physiological disorder attributed to high solar radiation and air temperatures. With climate change, this phenomenon will tend to expand to new areas, as the Mediterranean basin. The effects of 2 irrigation restitutions (100 and 70% of evapotranspiration) and 2 training systems (2D and 3D) were evaluated and related to plant water status, in two commercial apple orchards (both Gala varieties) in Italy, during summer 2021. Aluminum foils were applied to a number of fruit, for each treatment, and their temperature was monitored, along with that of control fruit (no aluminum foil), in the last 25 days before harvest. Sunburn occurred only where aluminum foil was applied, where the generally higher temperatures might have been caused by higher reflected irradiance. The results showed that the training system was highly influencing fruit temperature (p 0.0003), rather than deficit irrigation. A 2D-shaped tree will intercept regular quantities of solar radiation, hence fruit will adapt to higher light environments all along the season; in fact, only 1 fruit experienced sunburn. On the contrary, the 3D-shaped trees, having a more irregular canopy, produced 4 sunburned fruit. Assumptions can be made that prolonged exposure of fruit to higher irradiances, since early in the season, and consequently air temperatures, induced higher protection mechanisms against sunburn. An interesting corelation between stem water potential and control fruit temperature, revealed a strong negative relationship (p 0.006). Less stressed plants appeared to have less warm fruit. Suggestions arise that plant water status may play an important role, thus certain training systems that maintain lower water potentials, like a fruiting wall canopy, might help prevent sunburn damage. As fruit were damaged only due to the application of aluminum foils, one could conclude that solar radiation and air temperature levels were insufficient to cause sunburn in the trial
Apple russeting: the contribution of surface conductance in the early fruit growth development stages
No full textBiophysical fruit growth depends on a balance among the vascular and transpiration flows which enter/exit the fruit via phloem, xylem, and through the epidermis. There is a lack of information about how russet could influence fruit growth in apples by affecting these mechanisms. Two apple cultivars “Renetta Grigia di Torriana” (RGT) and “Golden Delicious” (GD) were monitored in their first stage of development determining fruit surface conductance (gc), as well as fruit growth parameters as absolute growth rate (AGR) and relative growth rate (RGR). The gc and growth behaviors of the two cultivars were compared to outline if there was a different fruit development pattern, assuming RGT has a more spread russet on its skin while GD is russet-free. The fruit gc was significantly higher in RGT compared to GD, after the manifestation of russeting on the skin surface while daily AGR and RGR trends were relatively similar between the cultivars. Thus, the fruit growth pattern in the initial stage of development suggests that the presence of russet does not affect daily fruit quantitative growth, but it does influence the within-day pattern. Fruit with higher gc have higher transpiration and xylematic fluxes thus inducing in the diurnal growth pattern a greater fruit shrinkage during the day followed by a higher recovery enlargement at night. This suggests a cultivar-dependent contribution of the vascular fluxes within the day that may be a cause-effect of russet development. Besides, this knowledge can provide hints on how to optimize resource inputs to the orchard shifting from a species-base to a cultivar-base water/environment requirement
POSSIBLE ROLE OF MANNITOL AS AN OXYGEN RADICAL SCAVENGER IN OLIVE
No full textAlong with mannose and sucrose, olive produces large amounts of mannitol in
photosynthesizing leaves. Leaf mannitol shows large variation among olive genotypes
and Sicilian cultivars with different leaf mannitol content were used in our trials to see
whether mannitol may function as an additional non-enzymatic system to protect cells
from oxygen radicals and photosystem damage. In one experiment, entire shoots of
‘Passulunara’, ‘Castriciana’, ‘Nocellara del Belice’, and ‘Moresca’ olive trees were
taken to a greenhouse, and mature leaves were treated with paraquat solution, which
generates oxygen radicals in presence of light. After 48 hours leaves were sampled,
photographed and percent of necrosis was quantified by digital image analysis.
Mannitol content was determined in control non-treated leaves positioned in the same
node as the paraquat-treated ones. The same experiment was repeated using fieldgrown
trees under full sun light. In both cases, a significant inverse relation was found
between leaf necrosis and mannitol content suggesting that mannitol may provide
some scavenging action on paraquat-generated oxygen radicals. In another experiment,
leaf gas exchange and chlorophyll fluorescence were measured on field-grown
‘Castriciana’ (higher mannitol) and ‘Nocellara del Belice’ (lower mannitol) trees in the
morning, at noon, and in the afternoon to quantify partitioning of absorbed energy
among net photosynthesis (JCO2), photoprotection by heat dissipation (non-photochemical
quenching, JNPQ) and by alternative electron transport and photorespiration
(JNC), formation of reactive oxygen species (ROS) and heat re-emission inactive
photosystem (PSII). ‘Nocellara’ reported higher JCO2 and JNC than ‘Castriciana’,
whereas JNPQ was similar in the two cultivars. Despite a greater amount of energy for
ROS formation, ‘Castriciana’ yielded a smaller percentage of inactive photosystems
compared to ‘Nocellara’. Also in this case mannitol may act as an additional oxygen
radical scavenger and explain the differences in photosystem inactivation between the
two olive cultivars
Apoplasmic and simplasmic phloem unloading mechanisms: Do they co-exist in Angeleno plums under demanding environmental conditions?
Full text linkBiophysical fruit growth depends on a balance among the vascular and transpiration flows entering/exiting the fruit via phloem, xylem and through the epidermis. There is no information on vascular flows of Japanese plums, a species characterized by high-sugar content of its fruit at harvest. Vascular flows of Angeleno plums were monitored by fruit gauges during late fruit development, under the dry environment of the Goulburn Valley, Victoria, Australia. Phloem, xylem flows and skin transpiratory losses were determined, as well as diurnal leaf, stem and fruit pressure potentials. Fruit seasonal development, skin conductance and dry matter accumulation were also monitored. Fruit grew following a double-sigmoid pattern, but fruit size increased only 3.1 g over the last 3 weeks of development. Fruit grew very little in the morning, primarily due to phloem inflows (0.05 g fruit −1 hr −1 ), while water left the fruit via the xylem. Negligible skin transpiration was recorded for vapour pressure deficit (VPD) values below 3 kPa. This growth pattern, in the absence of skin transpiration, suggests apoplastic phloem unloading. However, at VPD values over 3 kPa (e.g. from early afternoon to a peak around 18:00 h), transpiratory losses through the skin (up to 0.25 g fruit −1 hr −1 ) caused fruit to shrink, leading to enhanced phloem and xylem inflows (ca. 0.15 g fruit −1 hr −1 ), a scenario that would correspond to symplastic phloem unloading. Over 24 h the fruit showed a slightly negative total growth, consistent with fruit growth measured in situ during the season at weekly intervals. A few fruit species are known to alter their phloem unloading mechanism, switching from symplastic to apoplastic during the season. Our data support the coexistence in Japanese plum of different phloem unloading strategies within the same day
Sviluppo di un software per la mappatura della fioritura in frutteto a partire da immagini aeree
No full textIl carico fiorale di un frutteto dipende da molteplici fattori ed è uno dei primi indicatori produttivi.
La variabilità in fioritura di un impianto frutticolo rende infatti possibile la contemporanea presenza di
piante sia cariche che scariche di fiori, anche in prossimità tra loro (specialmente per cultivar ad alto
rischio di alternanza di produzione). Per queste ragioni è necessario sviluppare tecnologie capaci di
quantificare e mappare il numero di infiorescenze per pianta nel più breve tempo possibile al fine di utilizzare
questa informazione in un contesto di frutticoltura di precisione per le stime produttive ed il diradamento
a rateo variabile.
L’obiettivo del presente lavoro è stato quello di sviluppare una soluzione tecnologica capace di fornire
in tempi brevi e in modo completamente automatico una mappa di fioritura e informazioni utili per
attuare la giusta pratica di diradamento. La tecnologia alla base è un drone con buona precisione GNSS
e una telecamera RGB ad alta risoluzione (21 MP), al quale viene affiancato il software di analisi sviluppato
in questa ricerca. Quest’ultimo è in grado, mediante l’analisi delle immagini aeree, di restituire
sia una mappa di fioritura a livello di singola pianta che informazioni aggiuntive per la creazione di una
mappa di prescrizione, in un tempo di circa 12 min ha-1. L’attendibilità della stima del numero dei
corimbi per pianta è stata valutata manualmente contando il numero di infiorescenze su 100 piante.
Nella fase di sviluppo tecnologico, oltre alla veridicità della quantificazione dei fiori (r = 0.87 – 0.92) e
alla capacità di geolocalizzare e mappare il carico fiorale in tempi brevi, si è cercato anche di dare la
capacità all’algoritmo del software di adattarsi a diverse forme di allevamento: a parete (2D) e in volume
compatto (3D). Quest’ultima implementazione ha lo scopo di permettere l’uso della tecnologia in
quei contesti frutticoli caratterizzati da piccole superfici ed eterogeneità sia nelle specie che nelle forme
di allevamento.
Il componente principalmente innovativo del programma Python è il sistema di georeferenziazione
diretta delle immagini aeree, che, rispetto a metodi tradizionali di mosaicizzazione, è in grado di fornire
sostanziali riduzioni nei tempi d’analisi (140s vs 6h). Il sistema ha un errore medio nel localizzare la
pianta sul filare di circa 1m.
Il principale vantaggio di questa applicazione software è nei tempi di raccolta e analisi dati, in
quanto, per svolgere l’attività manualmente vengono impiegate circa 2 ore ha-1 per il solo campionamento
di 10-15 piante e 10 minuti per l’attività di mappatura. Differentemente, svolgendo l’intero processo
completamente in modo automatico, il conteggio viene effettuato su larghe estensioni e l’intero
processo di mappatura a livello di pianta impiega 12 min ha-1
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