Plant Genome III Conference

QUANTITATIVE TRAIT LOCI CONTROLLING RESISTANCE TO SEVERAL PEST AND DISEASES IN PEACH (PRUNUS PERSICA) AND IN A RELATED SPECIES, PRUNUS DAIDIANA.

1. INRA, Station de Recherches Fruitieres, Centre de Bordeaux, BP 81, 33883 Villenave d'Ornon cedex, France.
2. INRA, Station de Recherches Fruitieres Mediterraneennes, Centre d'Avignon, Domaine de Saint Paul, 84140 Montfavet, France.

A hybrid population, issued from a cross between two heterozygous Prunus, i.e., P. persica (variety Summergrand) and a related species, P. davidiana (clone 1908), was used as a source of resistance and analyzed for resistance to the following pathogens and pest ; Sphaerotheca pannosa, Taphrina deformans and Myzus persicae. This population, consisting of 78 plants, was also analyzed using isoenzyme and RAPD techniques. For isoenzyme analysis, 3 systems were used: amylase, alcohol dehydrogenase and malate dehydrogenase. For RAPD analysis, 500 primers from Operon were tested. Linkage groups were established using the Mapmaker software. Two maps were built: one for heterozygous loci in P. persica and one for heterozygous loci in P. davidiana. Heterozygous loci in both parents were included in both maps and used as bridges between them. For QTL detection, Mapmaker/QTL software was used. The genetic linkage map of P. persica consisted of 5 linkage groups containing 20 RAPD markers covering 82 cM. The genetic linkage map of P. davidiana consisted of 8 linkage groups containing 82 RAPD markers and the amylase. This map covers 800 cM, which is approximatively the presume size of the genome. Regarding resistance to Sphaerotheca pannosa, Tophrina deformans and Myzus persicae, several QTLs were found for each.