Molecular genetics of quantitative traits in tomato diallel crosses

Resumo

The purpose of this research was to evaluate molecular markers and some quantitative fruit traits,  in a complete diallel cross without reciprocals, among five tomato recombinant inbred lines and their hybrids. Amplified fragment length polymorphism  (AFLP) and pericarp polypeptide profiles were obtained in four stages of fruit maturity of 15  genotypes. Among other traits, fruit weight, titratable acidity, pH, shelf life, and firmness were evaluated. The percentages of polymorphism for molecular markers and for the genetic variability for quantitative characters were calculated in the recombinant lines, hybrids and total genotypes. Cluster analyses were done for each level of genetic variation. The percentage of polymorphism varied between 34 and 54% for AFLP, and between 40 and 78% for polypeptide profiles. Higher polymorphism was observed in the group of hybrids. The genetic variability was 100% for titratable acidity and 34% for firmness, and the highest values were found in the parents. The genetic similarity varied among genotypes according to the level of genetic variation; however, the clustering consistency of some recombinant lines and their hybrids was conserved, which evidenced associations among molecular and phenotypic data.