ABSTRACT. The effects of the fruit ripening mutant gene alcobaça (alc) and color development mutants, old gold-crimson (og^c) and high pigment (hp), on yield and post-harvest quality of tomato fruits were investigated. Five tomato hybrids were obtained by crossing near isogenic lines with Flora-Dade background [Flora-Dade (alc⁺/alc⁺ og^c+/og^c+ hp⁺/hp⁺), TOM-559 (alc/alc og^c+/og^c+ hp⁺/hp⁺), TOM-591 (alc/alc og^c/og^c hp⁺/hp⁺), TOM-593 (alc/alc og^c+/og^c+ hp/hp), and TOM-589 (alc/alc og^c/og^c hp/hp)] with the pollen parent line Mospomorist (alc⁺/alc⁺ og^c+/og^c+ hp⁺/hp⁺). Hybrid fruit was harvested at the breaker stage and stored on shelves at 15^oC and 60% relative humidity for 16 days, and then evaluated for firmness, development of red color, and carotenoid contents. The different genotypic combinations at the loci alc, og^c and hp had no effect on fruit yield. The alc⁺/alc hybrid genotype significantly increased fruit firmness and significantly delayed the development of red color in maturing fruit. Simultaneous usage of og^c+/og^c and hp⁺/hp promoted an increase in the red color and lycopene content of alc⁺/alc hybrids, but did not have any additional effect on fruit firmness.

Key words: Beta-carotene, Fruit firmness, Lycopene, Lycopersicon esculentum, Plant breeding, Ripening mutants