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

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.

Exogenous Application of Glycine Betaine on Sweet Cherry Tree (Prunus avium L.): Effects on Tree Physiology and Leaf Properties

Biostimulants, such as glycine betaine (GB), are a sustainable way to boost productivity and quality in fruit crops, even in adverse environment conditions. Sweet cherry (Prunus avium L.) is an important crop, which is very sensitive to abiotic stress. Known primarily for its fruits, its leaves are also rich in bioactive substances, which, however, still have no commercial value. There are no studies about the effects of GB exogenous application on biochemical parameters of sweet cherry leaves and few studies about effects in sweet cherry tree physiology. This study was conducted in a Portuguese sweet cherry commercial orchard. Lapins sweet cherry trees were treated with a commercial product based on GB, at two different concentrations (0.25% and 0.40%). The applications were performed at three different phenological stages, according to the BBCH (Biologische Bundesanstalt, Bundessortenamt und Chemische Industrie) scale: 77, 81 and 86 BBCH. Both GB treatments improved leaf water status, photosynthetic pigments, soluble solids content, total phenolic contents, and antioxidant activity, resulting in better leaf water status regulation, greater photosynthetic capacity, and higher antioxidant activity. These results shows that GB can benefit sweet cherry tree physiology and provide new opportunities for sweet cherry leaves valorisation.

An Early Calcium Loading during Cherry Tree Dormancy Improves Fruit Quality Features at Harvest

The possible role of an early calcium application via sprays (0.25, 0.5 and 1M CaCl2) on dormant buds to improve sweet cherry (cv. Ferrovia) fruit quality at harvest was investigated. Fruit quality characteristics were also investigated in response to the age of spurs, the ripening stage, and their interactions. Results indicate that calcium enters the dormant flower buds and the phloem but not to the dormant vegetative buds. At harvest, the levels of Zn, Mn, and Cu were declined in fruits by increasing CaCl2 doses of sprays. Fruit respiratory activity was higher and on–tree fruit cracking was lower in red-colour (unripe) cherries as well as in fruit that was produced by 2-year-old short spurs or by Ca-treated buds. Differences in the sweet cherry skin metabolic profiles were identified. Fruit produced from Ca-exposed spurs exhibited lower levels of ribose and other cell-wall-related sugars and higher sucrose, maltose, and quininic acid levels. Nutrient shift was increased in red cherries, while anthocyanins were boosted in the black ones. PCA analysis was performed between the high dose of calcium spray and a control for mineral element content and cherry quality traits. This study illustrates that the high dose of calcium application during bud dormancy can effectively improve sweet cherry fruit characteristics, in terms of calcium content, cracking incidence, and fruit set. Overall, the present study contributes to a better understanding of the impact of calcium nutrition in fruit crops, which will provide references for alternative nutrient management and quality control in sweet cherry production.

Preliminary Insights in Sensory Profile of Sweet Cherries

Sweet cherry (Prunus avium L.) is a fruit appreciated by consumers for its well-known physical and sensory characteristics and its health benefits. Being an extremely perishable fruit, it is important to know the unique attributes of the cultivars to develop cultivation or postharvest strategies that can enhance their quality. This study aimed to understand the influence of physicochemical characteristics of two sweet cherry cultivars, Burlat and Van, on the food quality perception. Several parameters (weight, dimensions, soluble solids content (SSC), pH, titratable acidity (TA), colour, and texture) were measured and correlated with sensory data. Results showed that cv. Van presented heavier and firmer fruits with high sugar content. In turn, cv. Burlat showed higher pH, lower TA, and presented redder and brightest fruits. The principal component analysis revealed an evident separation between cultivars. Van cherries stood out for their sensory parameters and were classified as more acidic, bitter, and astringent, and presented a firmer texture. Contrarily, Burlat cherries were distinguished as being more flavourful, succulent, sweeter, and more uniform in terms of visual and colour parameters. The results of the sensory analysis suggested that perceived quality does not always depend on and/or recognize the quality parameters inherent to the physicochemical characteristics of each cultivar.