IDENTIFICATION OF QUANTITATIVE TRAIT LOCI CONTRIBUTING TO FUSARIUM-WILT RESISTANCE ON AN AFLP LINKAGE MAP OF FLAX (LINUM-USITATISSIMUM)

An AFLP genetic linkage map of flax (Linum usitatissimum) was used to identify two quantitative trait loci (QTLs) on independent linkage gro ups with a major effect on resistance to Fusarium wilt, a serious dise ase caused by the soil pathogen Fusarium oxysporum (lini). The linkage map was constructed using a mapping population from doubled-haploid ( DH) lines. The DH lines were derived from the haploid component of Fz haploid-diploid twin seed originating from a cross between a polyembry onic, low-linolenic-acid genotype (CRZY8/RA91) and the Australian cult ivar 'Glenelg'. The AFLP technique was employed to generate 213 marker loci covering approximately 1400 cM of the flax genome (n = 15) with an average spacing of 10 cM and comprising 18 linkage groups. Sixty AF LP markers (28%) deviated significantly (P < 0.05) from the expected s egregation ratio. The map incorporated RFLP markers tightly linked to flax rust (Melamspora lini) resistance genes and markers detected by d isease resistance gene-like sequences. The study illustrates the poten tial of the AFLP technique as a robust and rapid method to generate mo derately saturated linkage maps, thereby allowing the molecular analys is of traits, such as resistance to Fusarium wilt, that show oligogeni c patterns of inheritance.