Early Bigi Research Articles

Orchard Net Covers Improve Resistance to Cherry Cracking Disorder.

Orchard net cover improves plant physiology, yield and fruit quality, pest and disease control, and anticipates fruit ripening. Moreover, this crop technology has been used to reduce natural cherry cracking (NCC). This is a serious physiological disorder that cracks the epidermis, the hypodermis, and the storage parenchyma layers of the fruit due to rainfall events near the harvest and it is related to low fruit osmotic potential and/or high fruit water permeability. This work aims to study the effect of orchard net cover on sweet cherry trees, cv. Early Bigi, in two harvesting years (2019 and 2021). The NCC, the induced cracking index (CI), and the cracking type incidence were determined. In addition, epicuticular and intra-cuticular wax content, biometric and physicochemical parameters were also evaluated. Net cover reduced the natural cracking index by 40%. High fruit weight values were observed in covered trees comparing to the control ones, with increases of 45% and 13%, in 2019 and 2021, respectively. A positive correlation was observed between CI and total soluble solids and a negative correlation between CI and wax content. Therefore, with forecasts of worsening heavy precipitation events near harvest, protecting cherry trees with nets will increase resistance to fruit cracking.

Innovative edible coatings for postharvest storage of sweet cherries

Sweet cherry is among the most appreciated fruits by consumers, due to its organoleptic and health-promoting properties. However, it is a fruit with reduced shelf life, which limits its availability on the market. Several strategies to improve shelf life of fruits are available, including the use of plant-based edible coatings. This work aims to study the postharvest effect of aqueous (A) and hydroethanolic (H) extracts of medicinal and aromatic plants (Mentha piperita L. (MP), Satureja montana L. (SM) and Thymus vulgaris L. (TV)), Aloe vera (Al), and chitosan (Qh) coatings on physical and quality parameters of cv. Early Bigi. Sweet cherries were stored at 2°C for 14 days (cold storage), then kept at 20°C for more three days to assess shelf life (+ 3 SL). All treatments reduced weight (average of 10%) and firmness (average of 0.9 Nmm-1) losses mainly at the end of cold storage + 3 SL, when compared to control samples (12% and 0.7 Nmm-1). The ripening index showed a delay (average of 20 and 14%, respectively to cold storage and cold storage + 3 SL) in its increase when using aqueous extracts of Satureja montana L. (SMA) and Thymus vulgaris L. (TVA) coatings. Coatings improved the overall antioxidant activity of sweet cherries, without negative effects on the content of bioactive compounds and on the sensory profile of fruits. SMA and TVA coatings present overall positive results, that might indicate that their use could be a safe, natural, effective, beneficial and innovative approach to preserve sweet cherry quality in postharvest storage.

Defining key parameters and predictive markers of ‘Early Bigi’ cherry consumer satisfaction by means of differential storage scenarios

To induce differences in sensorial characteristics, ‘Early Bigi’ cherries were exposed to various storage scenarios, including modified atmosphere packaging, 1-methylcyclopropene and methyl jasmonate treatments. Three classes of consumer acceptance (high, medium, and low) were defined and related to changes in standard quality, flavour perception and volatile organic compounds (VOCs) emissions. Consumer satisfaction in ‘Early Bigi’ cherries strongly depended on the acidity levels of the fruit and how the storage scenario modulated this parameter. Multivariate data analysis also revealed a clear relationship between acidity, VOCs emissions and flavour perception that determined fruit acceptance. In this cultivar, flavour perception and consumer satisfaction were also linked to specific volatile compounds. At harvest and during the first 15 d of cold storage, consumer satisfaction was found to mainly depend on high levels of ethyl butanoate, (Z)-3-hexen-1-ol and benzaldehyde and on the other side on low levels of ethyl acetate and ethanol, which were probably perceived as off-flavours or unpleasant compounds. Consumer satisfaction was also related to low levels of 2-methylbutyl butanoate, (Z)-2-hexenyl acetate, linalool and 3-methyl-2-butanol. It is, therefore, possible to envisage the use of these specific volatile compounds as markers for consumer satisfaction in ‘Early Bigi’ cherries and perhaps also in other cherry cultivars.

Rootstock Affects the Fruit Quality of 'Early Bigi' Sweet Cherries.

The cherry rootstock influences the performance of the scion cultivar. It has an effect on cherry fruit quality, tree growth, yield and yield efficiency and floral and foliar nutrition. In this work, the influence of Saint Lucie 64 and Maxma 60 rootstocks on the fruit quality traits of cv. Early Bigi was evaluated. For this, several parameters, namely fruit weight (FW) and size (FS), soluble solids content (SSC), pH, titratable acidity (TA), flesh firmness (FF), epidermis rupture force (ERF), color and sensory profile, were assessed. Results showed that the fruits from trees on Saint Lucie 64 presented higher FF and ERF values and, consequently, better texture. On the other hand, fruits from trees on Maxma 60 showed sweeter cherries (higher SSC). Moreover, these trees presented the darkest cherries (lower values of L*, a*, b*, C* and hue°) and the highest SSC. Therefore, although the trees on Saint Lucie 64 produced firmer cherries, it was those with the Maxma 60 rootstock that produced sweeter and darker fruits. In conclusion, both scion–rootstock combinations proved to be good options for the region of Resende.

Genotype- and tissue-specific metabolic networks and hub genes involved in water-induced distinct sweet cherry fruit cracking phenotypes

Sweet cherry fruit cracking is a complex physiological disorder that causes significant economic losses. Despite many years of research there is a lack of understanding of the mechanisms involved in cracking. Here, skin and flesh tissue from the cracking susceptible 'Early Bigi’ and the cracking tolerant ‘Regina’ cultivars were sampled prior and just after water dipping treatment to identify water-affected metabolic networks that putatively involved in fruit cracking. Primary metabolites, most strongly those involved in sugars and amino acid metabolism, such as glucose and asparagine, shifted in 'Early Bigi’ compared with ‘Regina’ tissues following water exposure. Comparisons between cultivars, tissues and dipping points identified significant differentially expressed genes. Particularly, genes related to abscisic acid, ethylene biosynthesis, pectin metabolism, expansins and aquaporins were altered in water-exposed tissues. To further characterize the role of these genes in cracking, their single nucleotide variants of the coding regions was studied in another eight sweet cherry cultivars, which differ in their sensitivity to cracking, revealing a strong link mainly between pectin metabolism-related genes and cracking-phenotypes. Integrated metabolomic and transcriptomic profiling uncovered genotypic- and tissue-specific metabolic pathways, including tricarboxylic acid cycle, cell enlargement, lipid and ethanol biosynthesis, and plant defense that putatively are involved in fruit cracking. Based on these results, a model which describes the skin and flesh metabolic reprogramming during water-induced fruit cracking in the susceptible 'Early Bigi’ cultivar is presented. Τhis study can help to explore novel candidate genes and metabolic pathways for cracking tolerance in sweet cherry.

Phenolic Profile and Bioactive Potential of Stems and Seed Kernels of Sweet Cherry Fruit.

Every year, large quantities of stems and pits are generated during sweet cherry processing, without any substantial use. Although stems are widely recognized by traditional medicine, detailed and feasible information about their bioactive composition or biological value is still scarce, as well as the characterization of kernels. Therefore, we conducted a study in which bioactivity potential of extracts from stems and kernels of four sweet cherry cultivars (Early Bigi (grown under net cover (C) and without net cover (NC)), Burlat, Lapins, and Van) were examined. The assays included antioxidant (by 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic) acid (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and β-carotene-linoleic acid bleaching assays), and antibacterial activities against important Gram negative and Gram positive bacterial human isolates. Profile and individual phenolic composition of each extract were determined by High-performance liquid chromatography (HPLC) analysis. Extracts from stems of cv. Lapins and kernels of Early Bigi NC presented high levels of total phenolics, flavonoids, ortho-diphenols and saponins. Excepting for cv. Early Bigi NC, major phenolic compounds identified in stems and kernels were sakuranetin and catechin, respectively. In cv. Early Bigi NC the most abundant compounds were ellagic acid for stems and protocatechuic acid for kernels. In all extracts, antioxidant activities showed a positive correlation with the increments in phenolic compounds. Antimicrobial activity assays showed that only stem’s extracts were capable of inhibiting the growth of Gram positive isolates. This new data is intended to provide new possibilities of valorization of these by-products and their valuable properties.

Cracking in Sweet Cherry Cultivars Early Bigi and Lapins: Correlation with Quality Attributes.

Fruit cracking is one of the main concerns in sweet cherry production and is caused by a heavy rainfall before and during the harvest. This physiological disorder leads to severe economic losses, which can be more or less effective depending on the cracked region of the fruit: in the cheeks (side cracks), in the stylar scar region, or in the stem cavity region. Sweet cherry cracking can be affected by several factors such as cultivar, growing conditions, rootstock, fruit size, flesh osmotic potential, cuticular characteristics of the skin, and stage of fruit development. In this sense, the objective of this work was to evaluate the cracking incidence in two sweet cherry cultivars (Early Bigi and Lapins grafted on “Saint Lucie 64” rootstock) and correlate the cracking index with other quality parameters. Fruits were harvested on 2 May (cv. Early Bigi) and on 27 May (cv. Lapins) 2019 at their commercial ripening stage. In the field, the total yield and the trunk cross-sectional area were determined for each tree in order to calculate the yield efficiency. In the laboratory, the cracking index was determined in 150 fruits without visual defects. In addition, fruit size and weight, wax content, flesh firmness, epidermis rupture force, total soluble solids, pH, titratable acidity, and maturity index of 30 fruits were also evaluated. In general, all the analyzed quality parameters were influenced by the cultivar, being that cv. Lapins presented larger, heavier, firmer, and sweeter fruits, with more acidity and higher maturation index. However, cv. Lapins also presented higher cracking index, which was positively correlated with all the parameters above-mentioned and negatively correlated with the wax content. In fact, cv. Early Bigi presented a high wax content and simultaneously a low cracking index. The stylar scar region cracks were the most prevalent in both cultivars. These results allowed us to conclude that, in the North Portugal region, the Lapins cherries presented better quality attributes than the Early Bigi cherries. However, the latter are still very valuable to the region due to its early ripening. Additionally, it was also possible to conclude that bigger, firmer, more mature, and with lower wax content cherries were more sensitive to cracking than the smaller fruits, soft-fleshed, less mature, and with higher wax content.

Sweet cherry cultivar testing in Slovenia

Vegetative growth, productivity and fruit quality of eleven sweet cherry cultivars (‘Early Bigi’, ‘Summertime’, ‘Sweet Early’, ‘Merchant’, ‘Vigred’, ‘Grace Star’, ‘Techlovan’, ‘Black Star’, ‘Staccato’ with ‘Biggareau Burlat’ [‘Burlat’] and ‘Kordia’ as standards) were evaluated. Trees on ‘Gisela 5’ rootstock were planted in spring 2008 in Bilje, Slovenia (Europe). The productivity of the cultivars, which ripen from the 1st to 7th week of the harvest season, was assessed for 6 production years. Tree growth after eight years of investigation was most vigorous in ‘Grace Star’ and ‘Black Star’ and weakest in ‘Summertime’. Cumulative yield and yield efficiency were significantly highest in ‘Grace Star’ and ‘Black Star’ (midseason cultivars) and lowest in the very late ‘Staccato’. The productivity of early cultivars was reduced in some years due to unfavourable weather conditions in the period before or during ripening. Reduced yields of late cultivars were primarily due to damage caused by Drosophila suzukii (Matsumura). ‘Sweet Early’ was more productive than ‘Burlat’. ‘Burlat’ had the lowest average fruit weight. The cultivars will be discussed in relation to the less favourable conditions for sweet cherry production in Slovenia due to climatic change, new pests and the suitability of rootstock ‘Gisela 5’.

Life ZERO RESIDUES: influence of the ripening degree on the odour composition of ‘Early Bigi’ cherries: study of their aroma potential as ingredient for the juice industry

Life ZERO RESIDUES: influence of the ripening degree on the odour composition of ‘Early Bigi’ cherries: study of their aroma potential as ingredient for the juice industry

New Training Systems for High-density Planting of Sweet Cherry

We assessed the vegetative growth and fruit production behavior of different sweet cherry cultivars grown using multiple new ultra-high-density planting (HDP) and training systems. An experimental orchard established in 2007 in the Ferrara province of Italy was used for this trial. The sweet cherry cultivars under evaluation were ‘Giorgia’ and ‘Grace Star®’ grafted on Gisela® 6; and ‘Black Star®’, ‘Early Bigi®’, ‘Early Star®’, ‘Ferrovia’, ‘Grace Star®’, ‘Kordia’, ‘Regina’, ‘Summit’, ‘Sweet Early®’, and ‘Sylvia’ grafted on Gisela® 5 rootstock. Each cultivar–rootstock combination was trained to spindle, V-system, or Super Spindle Axis (SSA). Planting densities ranged from 1905 trees/ha for spindle with Gisela® 6 to 5714 trees/ha for V-system and SSA with Gisela® 5. Vegetative growth, yield productivity, and fruit quality were evaluated. Among the three systems grafted on Gisela® 5, trees trained to the spindle system had the highest trunk cross-sectional area (26.2 cm2), followed by V-system (21.8 cm2) and SSA (20.2 cm2). Seven years after planting, ‘Ferrovia’ had the highest cumulative yield per hectare among cultivars on Gisela® 5, especially with V-system (50.5 t·ha–1) and SSA (52.2 t·ha–1) training systems. For cultivars on Gisela® 6, ‘Giorgia’ on had the highest cumulative yield per hectare after 7 years, but ‘Grace Star®’ on had higher production (≈14.0 t·ha–1 with V-system and SSA and 12.8 t·ha–1 with spindle) than ‘Giorgia’ in 2013.

HIGH DENSITY PLANTING FOR SWEET CHERRY ORCHARDS

While a number of training systems are suitable for increasing sweet cherry planting density, the V and vertical axis systems are perhaps best suited to the task. New ideas regarding tree shape include short trees grown using dwarfing rootstocks like the Gisela® series. Research now needs to discover ways to improve tree efficiency under dwarfing or semi-dwarfing rootstocks. We report two ongoing cherry training system trials. The first trial, now in year 3, compares the vertical axis, spindle and V training systems, the dwarfing rootstocks Gisela® 5 and Gisela® 6 in planting densities of 1,905 and 5,714 trees ha-1, and the cultivars (11) Early Bigi, Sweet Early, Early Star, Giorgia, Grace Star, Black Star, Summit, Sylvia, Ferrovia, Kordia and Regina. The second trial involves trees trained to vertical axis with ‘Kordia’ and ‘Ferrovia’ at ultra-high densities of 5,000 (4.0 x 0.5 m) and 6,666 (3.0 x 0.5 m) trees ha-1 in two orchards, both at year 6. Cumulative yield of ‘Ferrovia’ in the second trial at year 6 was 46.6 t ha-1. Cherry quality was very high: 88.8% of the fruit at the density of 5,000 trees ha-1 and 89.8% at 6,666 trees ha-1 were over 28 mm in diameter.