Plant & Animal Genome V Conference
Town & Country Hotel, San Diego, CA, January 12-16, 1997.
PAG-V: P220 - MAPPING QTL CONTROLLING RAPESEED RESISTANCE TO <i>Leptosphaeria maculans</i>
P220
MAPPING QTL CONTROLLING RAPESEED RESISTANCE TO Leptosphaeria maculans
PILET, MARIE-LAURE, Régine Delourme, Nathalie Foisset, Michel Renard
INRA, Station d'Amélioration des Plantes, BP 29, 35653 Le Rheu Cedex, FRANCE
Blackleg of crucifers, caused by Leptosphaeria maculans (asexual stage : Phoma lingam), is one of the most important disease of rapeseed (Brassica napus). Genetics of intraspecific resistance was investigated using molecular markers. Genomic regions controlling blackleg resistance at the adult plant stage were mapped using one haploid population (DH) of 171 lines, derived from the cross Darmor-bzh X Yudal. The rapeseed genetic map used includes 286 DNA markers on 19 linkage groups (Foisset et al., 1996, T.A.G., in press). The resistance of the DH lines to L. maculans was evaluated in field tests in 1995 and 1996. Plants were contaminated from infected plant stubbles from the previous year scattered in the field. The putative resistance QTL (Quantitative Trait Loci) were mapped using 'Interval mapping'. Blackleg notations at the adult stage in 1995 and 1996 allow the detection of 10 genomic regions with additive effects : among these, 5 QTL are common to the two years. Several year specific QTL are also detected (3 in 1995 and 2 in 1996). The total genotypic variation accounted for by additive QTL amounts to 52% in 1995 and 51% in 1996.