RAPD and SCAR markers linked to the sex expression locus M in asparagus

Abstract

Bulk segregant analysis (BSA), random amplified polymorphic DNA (RAPD) and sequence characterized amplified region (SCAR) methods were used to map molecular markers to the sex locus M of asparagus. Two parents, A19 (male, Mm) and MW25 (female, mm), and 63 progeny were used for the study. Two DNA bulks, one male and one female, were made by pooling equal amounts of DNA from 10 randomly selected progeny of each sex type. A total of 760 arbitrary decamer oligonucleotide primers were used for RAPD analysis. Primer OPC15 produced two RAPD markers, OPC15-98 and OPC15-30, both of which were linked to the M locus at a distance of 1.6 cM. Subsequently, amplified RAPD fragment OPC15-98 was cloned and sequenced. The sequence was then used to design flanking 24-mer oligonucleotide SCAR primers SCC15-1 and SCC15-2. Both of these SCAR primers amplified a single 980 bp fragment; the same size as the cloned RAPD fragment. However, the SCAR marker was dominant as was the original OPC15-98 band from which it was derived. These RAPD and SCAR markers could be used for scoring male and female progeny in the mapping population, but were not found to be applicable to other asparagus germplasm studied.