Plant Genome III Conference Plant Genome III Conference
Crown rust, caused by Puccinia coronata, is the most important fungal disease of cultivated oat. The primary strategy for combatting crown rust involves the use of resistant lines. The near-isogenic hexaploid oat line (NIL) D526 containing a gene which confers resistance to P. coronata race 345 was examined to identify molecular markers linked to the resistance gene. Randomly amplified polymorphic DNA (RAPD) and RFLP analyses were employed to identify molecular markers. Five hundred forty-seven RAPD primers were used to compare two DNA pools; each pool contained DNA from 10 BCIF3 plants identified as either homozygous resistant(resistant pool) or homozygous susceptible (susceptible pool) to P. coronata race 345. Five primers detected polymorphic bands which preliminary analysis indicated to be linked to resistance. Previous work has identified an RFLP clone (CDO1502) which detected a polymorphism tightly linked to the resistance gene (0.4 cM). A hexaploid oat map and maps of other Gramineae species were examined, and 12 RFLP clones linked to CDO1502 were identified. These clones were used to probe the resistant (D526) and susceptible (Lang) parental lines; 9 probes detected polymorphisms between the two parents, and preliminary analysis suggested that at least three of these probes detected polymorphic bands tightly linked to the resistance gene. Results of further analysis of both RAPD and RFLP markers on a BCIF2 population of hexaploid oat line D526 consisting of 424 individuals segregating for crown rust resistance will be presented.