Approximately 105 bands were obtained for each primer pair,
of which two to 25 markers were polymorphic between CO39
and Tadukan. A polymorphism of 17% was detected from 64
AFLP primer pairs used in the parental survey between CO39
and Tadukan. Interestingly, three AFLP markers (AF1: Eaca/M-ctt;
AF2: E-aca/M-cat and AF3: E-acc/M-cac2) were
found to co-segregate with the resistance gene in the F2
population from CO39 and Tadukan. Moreover, all three
markers were also found to cluster in the vicinity of this gene
with a map distance of 0.0 cM (Fig. 1). The co-segregating
AFLP bands were cloned directly from the denaturing
polyacrylamide gels with one round of PCR amplification.
However, multiple clones were obtained per marker band,
which is known to restrict the utility of the AFLP markers in
mapping and map-based cloning experiments (Shan et al.
1999, Cozijnsen et al. 2000). The three AFLP markers were
inseparable from the Pi38 gene with a map distance of 0.0 cM,
and two SSLP markers (RM206 and RM2) were linked to the
gene with distances of 4.0 cM and 16.0 cM, respectively
(Fig. 1).