Resumen de New Stable QTLs for Berry Firmness in Table Grapes
José Correa, Maribel Mamani, Claudia Muñoz Espinoza, Mauricio González Agüero, Bruno Defilippi B., Reinaldo Campos Vargas, Manuel Pinto, Patricio Hinrichsen R.
Berry firmness is one of the most important quality traits in table grape production and, consequently, a key aspect for table grape breeding programs. To identify the genes determining the berry firmness in grapes, a progeny of Ruby Seedless × Sultanina (n = 137) was evaluated during three consecutive seasons. Results showed that even though the heritability was ~90%, season had an important effect on this trait. Quantitative trait loci (QTL) analysis and genetic mapping showed that the determinants for this trait are distributed in linkage groups 8 and 18. This is the first time that a stable QTL for berry firmness across seasons has been identified on linkage group 8. This QTL is mainly given by a male allelic and additive effect. Together, these two QTLs explained ~27.6% of the phenotypic variance, with confidence intervals of up to 10 cM. Among the tens of genes found in these two QTLs, we highlight a cation/calcium exchanger, a xylosyltransferase, a probable cellulose synthase, and a putative invertase. This study shows that berry firmness has a clear genetic basis. These results could also be used for the development of markers to assist table grape breeding.
