The Effect of Climatic Parameters on Strawberry Production in a Small Walk-In Greenhouse

Variability in strawberry tunnels impacts fruit quality and limits melatonin effects

BACKGROUND

Fluctuations in environmental conditions within fields and crop plant performance can greatly affect production and quality standards. These factors are particularly relevant for producers, who require sustained optimal production to profit from small margins. Fluctuations might be exacerbated at the end of the crop season, where neither of the aforementioned factors are optimal. In the present integrated study, we assess strawberries' nutritional quality and the impact of harvest timing, tunnel conditions and inter-individual variability in a Mediterranean production tunnel divided into blocks, where two harvests were performed 3 weeks apart. In addition, the effects of sprayed melatonin at the end of productive season were also evaluated.

RESULTS

End-season harvesting negatively impacted fruit hydration, antioxidant capacity and ripening-related hormones in strawberry fruits. Additionally, tunnel distribution influenced fruit nutritional quality, with light radiation being the main variable factor disturbing antioxidant contents. Nutrients exhibited high inter-individual plant variability, accounting for 20% variation, and were strongly correlated with fruit hydration and ripening-related phytohormones. Finally, melatonin applications affected neither fruit production, nor nutritional parameters, for which the effects were masked by the intrinsic strawberry variability. Overall, the results underline the limitations of this type of application for field implementation.

CONCLUSION

Fruit quality variation in strawberry fields is explained by environmental and inter-individual variability. Likewise, the implementation of regulatory molecules such as melatonin in field applications relies on crop homogeneity and might have limited applicability in heterogeneous productive systems. Consequently, identifying and reducing microclimate variability in productive fields is paramount for advancing agricultural practices to uphold unwavering standards on fruit quality. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

On the Assessment of Strawberries' Shelf-Life and Quality, Based on Image Analysis, Physicochemical Methods, and Chemometrics

The aim of the present study was to evaluate Marisol strawberries' (Fragaria × ananassa) physicochemical quality and shelf-life during storage, using an integrated analytical approach. More specifically, the research aimed to assess the strawberries' color, texture, and nutritional quality, over an 11-day storage period, employing physicochemical analyses, spectrophotometric assays, Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) spectroscopy, image analysis, and statistical tools. The results revealed significant changes in the outer surface texture and color characteristics, indicating spoilage progression. Physicochemical parameters such as water activity, moisture content, soluble solids, titratable acidity, and ascorbic acid content exhibited significant alterations, influencing the taste profile and freshness perception. Antioxidant and antiradical activities showed fluctuations, suggesting a potential decrease in phenolic content during storage. Moreover, the ATR-FTIR spectra findings confirmed the results regarding the moisture content, soluble solids, and total phenolic content. The integration of physicochemical and image analysis-derived features through a principal component analysis (PCA) enabled the accurate classification of samples based on storage days. Regression analysis, using these features, successfully predicted the storage day with high accuracy. Overall, this integrated analytical approach provided valuable information on the estimation of Marisol strawberries' shelf-life and the prediction of their quality deterioration, contributing to better fruit management and the minimization of discards.

Quantifying Chilling Injury on the Photosynthesis System of Strawberries: Insights from Photosynthetic Fluorescence Characteristics and Hyperspectral Inversion

Chilling injury can adversely affect strawberry bud differentiation, pollen vitality, fruit yield, and quality. Photosynthesis is a fundamental process that sustains plant life. However, different strawberry varieties exhibit varying levels of cold adaptability. Quantitatively evaluating the physiological activity of the photosynthetic system under low-temperature chilling injury remains a challenge. In this study, we investigated the effects of different levels of chilling stress on twenty photosynthetic fluorescence parameters in strawberry plants, using short-day strawberry variety "Toyonoka" and day-neutral variety "Selva" as representatives. Three dynamic chilling treatment levels (20/10 °C, 15/5 °C, and 10/0 °C) and three durations (3 days, 6 days, and 9 days) were applied to each variety. WUE, LCP, Y(II), qN, SIFO2-B and rSIFO2-B were selected as crucial indicators of strawberry photosynthetic physiological activity. Subsequently, we constructed a comprehensive score to assess the strawberry photosynthetic system under chilling injury and established a hyperspectral inversion model for stress quantification. The results indicate that the short-day strawberry "Toyonoka" exhibited a recovery effect under continuous 20/10 °C treatment, while the day-neutral variety "Selva" experienced progressively worsening stress levels across all temperature groups, with stress severity higher than that in "Toyonoka". The BPNN model for the comprehensive assessment of the strawberry photosynthetic system under chilling injury showed optimal performance. It achieved a stress level prediction accuracy of 71.25% in 80 validation samples, with an R2 of 0.682 when fitted to actual results. This study provides scientific insights for the application of canopy remote sensing diagnostics of strawberry photosynthetic physiological chilling injury in practical agricultural production.

Bioactive Ingredients with Health-Promoting Properties of Strawberry Fruit (Fragaria x ananassa Duchesne)

Strawberries (Fragaria x ananassa Duchesne) belong to the berry group and are characterized primarily by delightful sensory properties. Due to their chemical composition, these fruits are a rich source of bioactive compounds that can modify the metabolic and physiological functions of the body. The aim of this work is to present the current state of research on bioactive ingredients found in these fruits in the context of their health-promoting properties. The paper presents compiled and reviewed data on the content of polyphenolic compounds, organic acids, and vitamins, especially vitamin C, in strawberries. The content of these compounds is influenced by many different factors that are discussed in the paper. It also draws attention to the presence of oxalates and allergenic compounds, which are classified as anti-nutritional compounds of strawberries.

Prunus lusitanica L. Fruits: A Promising Underexploited Source of Nutrients with Potential Economic Value

In recent times, less-known fruit species have increasingly attracted worldwide attention and their health benefits are at the forefront. The fruits of plants from the genus Prunus are good sources of nutrients due to their economic, agronomic, and healthy values. However, Prunus lusitanica L., commonly known as Portuguese laurel cherry is considered an endangered species. Thus, the present work aimed to monitor the nutritional components of P. lusitanica fruits grown in three locations in northern Portugal for four consecutive years (2016-2019), using AOAC (Association of Official Analytical Chemists), spectrophotometric, and chromatographic analysis. The results evidenced the abundance of phytonutrients in P. lusitanica, such as proteins, fat, carbohydrates, soluble sugars, dietary fibre, amino acids, and minerals. It was also highlighted that the variation of nutritional components was relatively linked to the year factor, being especially relevant in the frame of the current changing climate, among others. These findings suggest that P. lusitanica L. deserves to be conserved and planted because of its food and nutraceutical applications. However, more detailed information on this rare plant species, such as phytophysiology, phytochemistry, bioactivity, pharmacology, etc., is certainly required for the design and development of appropriate uses and valorization alternatives for this species.

Survey on technical management of strawberries in Morocco and evaluation of their post-harvest microbial load

The climatic conditions of the growing regions influence the fruit's microbiological quality and their tolerance to post-harvest pathogens. The present work aims to identify the prevalence of bacterial and fungal strains of strawberries (Fragaria × ananassa) in the Gharb and Loukkos regions of Morocco. Thus, to establish a correlation between the microbial load and the climatic conditions of the two targeted regions. The bacteriological analyses were studied according to the International Organization for Standardization (ISO) methodologies. Regarding the mycological study, fungal species determination was performed using identification keys. Yeast species determination was done using genus analysis, assimilation, and fermentation tests. Emberger bioclimatic quotients (Q2) were calculated for the Gharb and Loukkos regions and bioclimatic stages were determined. Salmonella spp. was not detected in the studied samples. However, Listeria monocytogenes and Escherichia coli were isolated from the Gharb samples. Sulfite-reducing clostridia spores were found in two Gharb samples versus one Loukkos sample. Coagulase-positive staphylococci were negative in all samples analyzed. Loukkos and Gharb regions were contaminated by Bacillus cereus with percentages of occurrence of 5.2 and 7.8%, respectively. The fungi found in strawberries from both regions were Aspergillus niger, Botrytis cinerea, Fusarium spp., Penicillium spp., Rhizopus spp., and Alternaria alternata with a significant predominance in the Loukkos samples. Indeed, a marked presence is noted for Candida sake and Rhodotorula glutinis in strawberries from Loukkos. Gharb is located on the semi-arid stage, while Loukkos is located on the sub-humid stage. Climatic conditions have a strong influence on plant microbial load, which explains the prevalence of bacteria in strawberries from Gharb and the prevalence of fungi in strawberries from Loukkos.

Effect of Temperature on Soluble Solids Content in Strawberry in Queensland, Australia

Warmer conditions under climate change will alter plant, flower and fruit development in strawberry (Fragaria × ananassa Duch.). Most of the studies examining the relationship between soluble solids content (SSC) and temperature have been conducted in areas with a temperate or Mediterranean climate. I investigated the link between SSC and temperature in Queensland, Australia. Potted plants of ‘Festival’, ‘Fortuna’, ‘Brilliance’, ‘Beauty’ and ‘Red Rhapsody’ were planted on 19 April 2021 and information collected on productivity, SSC and titratable acidity (TA) from 14 July to 6 October. Additional data were collected on the concentrations of the main soluble sugars in the fruit from 4 August to 6 October. Nights were 2 to 4 °C warmer than the long-term average conditions from 1965 to 1990. Marketable yield was lower in ‘Beauty’ and higher in the other cultivars. Fruit were smaller in ‘Festival’, ‘Fortuna’ and ‘Beauty’ and larger in ‘Brilliance’ and ‘Red Rhapsody’. Mean (±SE or standard error) SSC pooled across the cultivars was 7.6 ± 0.05%, and mean TA was 0.59 ± 0.005%. Fructose (30.2 ± 0.2 mg/g FW) and glucose (27.1 ± 0.3 mg/g FW) were the main sugars in the fruit, with lower concentrations of sucrose (0.05 ± 0.02 mg/g FW) and maltose (less than 1 mg/g FW). The mean concentration of all the sugars was 57.4 ± 0.5 mg/g FW. Soluble solids content decreased from 8.6 to 6.8% as the average daily mean temperature in the eight days before harvest increased from 14.5 to 19.5 °C (p < 0.001, R2 = 0.72). These results are consistent with similar studies in Florida and suggest that higher temperatures in the future will decrease fruit quality in subtropical locations.