SPECIFIC MOLECULAR MARKER OF THE GENES-CONTROLLING LINOLENIC ACID CONTENT IN RAPESEED

in rapeseed, which is an agronomically important oilseed, variation in the linolenic acid content of the oil has been obtained through chemi cal mutagenesis treatment. Conventional breeding of this quantitative trait, however requires specific molecular markers. By means of bioche mical experiments, Rie have established that the induced variation in linolenic acid content is associated with the fad3 gene encoding the m icrosomal Delta(15) desaturase. Using a pair of primers specific to th is gene and a doubled haploid progeny derived from a row linolenic x h igh linolenic acid F-1 hybrid, we have identified a polymorphism of th e fad3 alleles between the low- and the high-linolenic acid genotypes. The structure exon/intron of the fad3 DNA sequence seems to be very s imilar to that of the Arabidopsis fad3 gene. The choice of the primer pair allows specific amplification of one of tile two rapeseed fad3 ge nes. The value and contribution of specific markers to conventional pl ant breeding is discussed.