We have evaluated eight varieties of strawberry, seven short-day and one day-neutral, for two years with two sampling dates and two repetitions by date. The fruits were collected and evaluated at the ripe stage. Contents of sucrose, glucose, fructose, ºBrix, citric acid, ascorbic acid and malic acid in the fruit were measured. The data were analyzed using principal component analysis (PCA) and Pearson correlations. The PCA groups most of the variability in the first component (62.2%). This component shows a positive relationship between the Brix degrees, sugars and acids (higher values of this component indicate increased Brix degrees, and the contents of sugars and acids). The second component collects 20.74% of the variability, which is mainly related to differences in the sugars/acids ratio. The plotting of the factor barycenter over the two principal components of PCA analysis shows that second harvest date has a higher content of sugars, organic acids and ºBrix. With regard to varieties representation over PCA, the good quality variety "Primoris" is characterized by a high sugar content and a balanced total sugars/acids ratio. Moreover, the variety of day-neutral "Nieva" shows the lowest values of sugars, acids, ºBrix and total sugars/acids ratio. Featured correlations exist between ascorbic acid content and glucose and fructose content (R² = 0.82 and 0.81, respectively). The ºBrix shows a relative correlation with the total sugars content (R² = 0.74). In conclusion, the genotype has large effect in the content of sugars and organic acids. Therefore, the high content of sugars and acids and a balanced relationship between them could be used as a quality trait for the selection of strawberry varieties. On the other hand, ºBrix is relative good measure of the total sugar content.

In the last few years organoleptic and nutritional traits have become the major breeding targets in most strawberry breeding programs all over the world. Furthermore, the joint improvement of the nutritional value and the sensory key parameters of strawberry might increase the consumption rate of this fruit, which in turn will have a positive effect on consumer's health and a positive economic impact on the producing areas. New cultivars and strawberry selections bred in Huelva (Southwestern Spain) have been characterized in relation to their organoleptic and nutritional properties. Key metabolites associated to the strawberry flavor (sucrose, fructose, glucose, malic and citric acid and 20 main volatile compounds) as well as specific phytochemicals (nine phenolic compounds plus vitamin C) with relevant antioxidant capacities have been analyzed by high resolution gas chromatography coupled to mass spectrometry (HRGC-MS) and high performance liquid chromatography (HPLC). Data were analyzed using principal component analysis (PCA) and Pearson correlations to discriminate those strawberry selections that, besides good agronomic performances, produce fruits with high contents of key flavor components and health-promoting phytochemicals. PCA clearly distinguish selections A10-48-3 and A7-32-10 as having significantly different metabolic profiles and displaying the highest contents of sugars, organic acids, ethyl esters, mesifurane, terpineol, quercetin and vitamin C.

No abstract

Strawberry fruit has a short post-harvest shelf life because it is very perishable and susceptible to several pathogens that quickly reduce the quality of the fruit. A large part of Huelva's strawberry production is exported, so the shelf life of the fruit is one of the main factors that determines the quality of the fruit when it reaches its destination. The aim of this work was to explore the relationship between postharvest shelf life and the agronomic and quality traits in different strawberry genotypes during several seasons.For this, the postharvest shelf life, early and total yield, soluble solids content, fruit firmness and the content of sugars and organic acids were quantified during four consecutive seasons (2016-2019). First, the relationships of the shelf life with the other variables were explored through a principal components analysis. Subsequently, the variables that showed a stronger association with the shelf life were analyzed in more detail by correlation and linear regression analysis.The principal components analysis showed a positive relationship of the shelf life with the acid content and with fruit firmness measured with dynamometer and subjectively. Specifically, the correlation between the shelf life and firmness (measure with a penetrometer and subjectively) and the total acid was 0.59, 0.48 and 0.53, respectively. In conclusion, the variables of firmness and acid content can be useful to select genotypes in a strawberry breeding program with an increased shelf life.

No abstract