Germinação de sementes de tomateiro em diferentes temperaturas: Variabilidade fenotípica e heterose

Abstract

Exploitation of the existing genetic variability in tomato germplasm via breeding strategies is one alternative to improve the germination under adverse environmental conditions and to provide seeds with better quality and performance. The rate and percentage of germination of tomato seeds are influenced by several genetic and environmental factors. Temperature is one of the major factors capable of influencing tomato seed germination parameters. In the present work, the female and male inbred lines of four fresh-market tomato hybrids (San Vito, Duradoro, Finestra, and Fontana) as well as the reciprocal (maternal line x paternal line and paternal line x maternal line) F1 crosses were evaluated for seed quality traits and germination ability at different temperatures. The seed traits were evaluated using five tests: mass of 1000 seeds; germination at 15°C, 25°C, and 35°C; first count at 15°C, 25°C and 35°C, accelerated aging, and seedling emergence. Higher temperatures (35°C) decreased the germination in all evaluated accessions. Significant effects of the inbred lines on performance of the hybrids were observed for germination at different temperatures as indicated by the analysis of the reciprocal crosses. Maternal (female) effects were observed for some traits in the hybrids San Vito and Fontana. Male effects were observed for the hybrid Finestra. Heterotic effects were observed for some traits in the hybrids San Vito and Finestra.