R. Ford et al., Genetics of resistance to ascochyta blight (Ascochyta lentis) of lentil and the identification of closely linked RAPD markers, THEOR A GEN, 98(1), 1999, pp. 93-98
Foliar resistance to Ascochyta lentis is controlled at a single major locus
by a dominant gene (AbR(1)) in the lentil accession ILL5588 (cv 'Northfiel
d'). Flanking RAPD markers that are closely linked to the resistance locus
in coupling phase were identified by bulked segregant analysis. Out of 261
decanucleotide primers screened 7 produced a polymorphic marker that segreg
ated with the resistance locus, and all markers were found to exist within
a single linkage group. Five of the seven RAPD markers were within 30 cM of
the resistance locus. Log likelihood analysis for detecting QTL associated
with the foliar resistance revealed that a single narrow peak accounted fo
r almost 90% of the variance of resistance between the bulks. Preliminary m
apping in an Fg population revealed that the closest flanking markers were
approximately 6 and 14 centiMorgans (cM) away from the resistance locus. Th
ese markers should be useful for the discrimination of resistant germplasm
through marker-assisted selection in future breeding programmes and represe
nt the first essential step towards the map-based cloning of this resistanc
e gene.