Tomato second cycle hybrids differ fron their parents at three levels of genetic variation

LIBERATTI, D.R.; RODRIGUEZ, G.R.; ZORZOLI, R; PRATTA, G.R.

International Journal of Plant Breeding

Global Sciences Books

Lugar: Tokyo; Año: 2013 p. 1 - 6

1752-3478

Second Cycle Hybrids (SCHs) are produced by intercrossing Recombinant Inbred Lines (RILs) derived from the F2 generation of two homozygous parents. Three tomato (Solanum lycopersicum) SCHs were obtained by crossing six RILs derived from an interspecific cross S. lycopersicum x S. pimpinellifolium. The objective was to characterize these SCHs and their parental RILs at different levels of genetic variation to understand the genetic causes underlying outperforming of these new genetic combinations. Fruit quality traits, pericarp polypeptide profiles at four ripening stages and AFLP were assessed. The degree of genetic determination and the degree of dominance were calculated for phenotypic traits, and the molecular polymorphism was evaluated for polypeptide and AFLP profiles. SCHs contributed with extreme values for some fruit quality traits, for which non additive gene actions were prevalent. Molecular differences were higher for polypeptide than for AFLP profiles, de novo bands being relevant to explain the increase in SCHs polymorphism. Cluster analysis showed different association among SCHs and RILs according to the level of genetic variation under study, providing a first advance for understanding the biological basis underlying the SCHs outperforming.