Investigation of the morpho-biochemical composition of fruits of new Armenian tomato breeding lines

Background: Tomato breeding plays a crucial role in meeting the demands of the healthy food market and ensuring food security. Modern agricultural approaches focus on improving the qualitative and functional characteristics of fruits. Additionally, the development of new genotypes adapted to local growing conditions and enriched with biologically active compounds is a key priority in agricultural science. Such plants serve as valuable genetic material for the creation of domestic hybrids, reducing dependence on imported varieties. Objective: To evaluate the morphological and biochemical characteristics of new Armenian tomato breeding lines – R-Bf-04, R-St-13, R-Zd-02, R-Gr-12, and R-At-23 – under protected cultivation conditions, with the aim of identifying promising genotypes for inclusion in hybridization breeding programs. Methods: The research was conducted from 2022–2025 under winter-spring vegetation conditions in a greenhouse. The morphological traits of the breeding lines were assessed in accordance with international descriptors. Biochemical parameters of the fruits, including total sugar, phenolic compound, ascorbic acid, carotenoid, and lycopene content, were determined using spectrophotometric methods. Statistical data analysis was performed using analysis of variance (ANOVA) at a significance level of p ≤ 0.05, as well as Pearson correlation analysis. Results: The morphological and biochemical evaluation of the tomato breeding lines revealed a wide variability in the studied traits. Fruit weight ranged from 182.3-255.2g, reflecting differences in morphological type and yield potential. Ascorbic acid and total phenolic content varied from 19.64-22.76mg/% and from 32.4-48.4mg GAE/100g, respectively, indicating diversity in antioxidant activity among the lines. Total carotenoids ranged from 2.56-4.82mg/100g, while lycopene content ranged from 2.36-4.44mg/100g, with lycopene accounting for up to 92% of the total carotenoids. Significant differences were observed in organoleptic parameters, including sugar content, titratable acidity, and sugar–acid ratio, all of which influence fruit flavor quality. Correlation analysis revealed strong positive relationships among sugar content, dry matter, carotenoids, phenolic compounds, and ascorbic acid (vitamin C). The most balanced quality parameters were demonstrated by the R-Bf-04 and R-At-23 lines, along with the control variety, Zvartnots, underscoring their high value for further breeding aimed at improving fruit quality. Novelty: For the first time, a comprehensive morphological and biochemical characterization of new Armenian tomato breeding lines grown under protected cultivation was conducted. The obtained data reveal a wide range of genetically determined variability in key fruit quality traits. Several lines were identified as having significant potential for inclusion in breeding programs aimed at improving organoleptic properties and enhancing the content of biologically active compounds. Conclusion: The conducted evaluation revealed a significant genetic potential of the tomato breeding lines, each exhibiting a unique combination of valuable traits that contribute to improved fruit quality. These lines may serve as promising donors in hybridization programs aimed at developing tomatoes with enhanced functional value and the ability to successfully compete with imported hybrids. Keywords: tomato, breeding lines, morphological traits, biochemical composition, ascorbic acid, phenolic compounds, carotenoids, lycopene, organoleptic qualities, sugars