Fruit quality and yield-related traits of intraspecific recombinant inbred lines developed for novel fruit color of tomato (Solanum lycopesicum L.)

The current study was designed with the aim of: i) developing a recombinant inbred line (RIL) population for novel fruit color, and ii) phenotyping RILs for agronomic and fruit quality traits. The population was initiated from a cross between pink- and orange-fruited tomato (Solanum lycopersicum L.) genotypes. Parents were selected in order to diversify tomato color and to introduce resistance against Tomato mosaic virus (ToMV). Ninety-three F6 RILs and five F₆ lines from single plant selection along with parental lines were used in a phenotyping trial. Morphological and agronomic traits were assessed by 30 qualitative and quantitative tomato descriptors. The following fruit quality traits were characterized at the full maturity stage: exterior fruit color, fruit firmness, soluble solids content (SSC), ascorbic acid content, total polyphenols (TP), and antioxidant activity (AA). Four main colors were observed in the RILs: orange, pink and red as well as a novel orange-pink color. CIELab parameters of fruit exocarps exhibited significant changes among the groups pre-defined based on visual color assessment. The most notable differences were observed in the a* component (green to red) where pink and red fruits had higher values than fruits with orange and orange-pink colors. In contrast, the L* (white to black) and b* (blue to yellow) components in the orange and orange-pink fruits were higher than those in the pink and red fruits. The higher chroma in the groups with orange and orange-pink fruit, indicating more purity of the color, may indicate high consumer acceptance. According to hue angle (color tone), the orange-pink color is closer to orange than to pink. Besides the external fruit color, variation in traits, such as inflorescence type, fruit shape and weight, productivity, fruit firmness, SSC, ascorbic acid content, TP and AA were also observed to aid in the selection of elite breeding lines with orange-pink fruit.