Traditional Sweet Peppers as Resources for Internal Fruit Quality: Evidence from Experimental F1 Hybrids Across Two Organic Growing Environments

Traditional sweet pepper germplasm represents a valuable source of variation in fruit quality traits for hybrid breeding and sustainable production. Although hybridization has mainly exploited heterosis for yield and related traits, its effect on fruit quality remains underexplored. In this single-year study, traditional Spanish genotypes and their hybrids, derived from crosses with modern virus-resistance donor lines, were evaluated in two organic environments in southeastern Spain: open-field conditions in Valencia and greenhouse conditions in Murcia. Sugars, vitamin C and flavonoids were determined by HPLC, while red and yellow-orange carotenoids were assessed spectrophotometrically. Genotype × environment responses, heterosis, principal component analysis and trait correlations were also evaluated. Genotype explained substantial variation in sugars, vitamin C and carotenoids, whereas environment was the main factor for flavonoids. Significant G × E interactions were detected for all traits. Sugars and vitamin C differed less between the two environments, while flavonoids and carotenoids tended to reach higher levels in the open-field trial. Positive mid-parent heterosis was more frequent than best-parent heterosis, highlighting P10 × P5 in sugars (26%, open-field), P6 × P10 in vitamin C (33%, greenhouse), P9 × P10 in flavonoids (82%, open-field) and P10 × P2 in carotenoids (87%, open-field). These results identified promising traditional genotypes and hybrids with high internal fruit quality under the tested conditions, although multi-year confirmation is needed.