Proceedings of the XLVI Italian Society of Agricultural Genetics - SIGA Annual Congress

Giardini Naxos, Italy - 18/21 September, 2002

ISBN 88-900622-3-1

Poster Abstract - 4.52

GENETIC MAPPING AND DETECTION OF QTLs FOR DISEASE RESISTANCE AND BERRY FLAVOUR IN GRAPE

SEVINI F.*, MARINO R.*, ZULINI L.**, MOSER S.***, GRANDO M.S.*

*) Lab. of Molecular Genetics

**) Plant Protection Unit

***) Chemistry of Food and Beverages Unit

Istituto Agrario di San Michele all’Adige, Via Mach 1, 38010 San Michele a/A, Trento, Italy

Vitis, linkage map, QTL, downy mildew, berry flavour

The development of genetic linkage maps provides a direct method for selecting desirable genes by their linkage to easily detectable molecular markers and the use of these maps for quantitative trait loci (QTL) analysis is a powerful approach for studying the inheritance of complex traits. These molecular techniques allow to overcome some biological limitation for breeding of Vitis spp. introducing traits of interest in a wide variety of populations by marker assisted selection (MAS).

For these purposes, a mapping population of one hundred seedlings derived from an interspecific cross between the aromatic grapevine Moscato bianco and an accession of Vitis riparia , tolerant to major fungus diseases, was developed to detect QTL for resistance to downy mildew (Plasmopara viticola ) and for fruit quality. Parental linkage maps contain 400 AFLPs generated by 50 selective amplifications and about 110 VMC SSRs that allowed identification of homologous linkage groups and maps integration. In addition, the segregation of new markers deriving from grape EST sequences related to defence in plants are now being evaluated in the whole progeny.

QTL analysis for downy mildew resistance traits is in progress, based on segregation data of individual responses following natural and artificial infection with Plasmopara viticola sporangia. Cuttings of the seedling population are also rated for sporulation, chlorosis and necrosis after artificial inoculation in greenhouse controlled conditions.

Berry composition from a subset of progeny individuals are now analysing by GC to identify secondary metabolites involved in Muscat flavour. These aromatic compounds will be than quantified at grape harvest for further segregation analysis.