A meta-analysis to assess the relationships between the application of different biostimulants, weight, diameter, and sugar content in citrus fruits

Abstract

The objective of the present study was to determine the statistical relationships among fruit weight, diameter, and sugar content, as well as to evaluate the significance of biostimulant treatments in affecting these parameters.The data were gathered from the author's prior B.Sc. thesis, which involved testing seven distinct biostimulants on many citrus cultivars during the 2023–2024 season, is expanded upon in this M.Sc. study. Citrus fruit quality is influenced by intricate relationships between hormone balance, nutrient uptake, and sugar transport mechanisms, according to prior research. Biostimulants, including humic acids, seaweed extracts, and amino acid formulations, have been shown to improve these physiological processes in a variety of environmental settings. Multivariate linear regression, Pearson correlation, and Principal Component Analysis (PCA) were used to analyze the data. A revised dataset that represented 50% of the original sample was produced by including those fruits for which sugar content measurements were available. PC1, PC2, and PC3 accounted for 68.25%, 29.25%, and 2.48% of the total variance, respectively, according to the PCA. Fruit weight and diameter were the main factors related with PC1, while sugar content had a significant impact on PC2. Weight and diameter had a strong positive link, but sugar levels had a negative correlation, according to correlation analysis. The observed patterns were validated using regression models that showed statistically significant fits (p < 0.05) (R2 = 0.72 for weight, 0.59 for diameter, and 0.65 for sugar). While Trainer yielded moderate advantages, Stim82 consistently increased fruit size and decreased sugar concentration among all treatments. Nova had higher sugar levels, demonstrating the clear variations between the varieties. These results highlight the significance of product design and harvest time in citrus quality improvement, confirming the inherent trade-off between fruit growth and sweetness.