Abstract:
Landraces and wild relatives of wheat are rich repositories of new rust resistance genes. Landraces
are preferred over wild relatives for the absence of deleterious effects associated with large alien
segments.A common wheat landrace, AUS 27969 (ex Portugal), from the Watkins Collection was
resistant under field conditions and produced seedling infection type (IT) 2C against the widely
virulent Australian Puccinia striiformis f. sp. tritici (Pst) pathotype 134 E16 A+ Yr17+ Yr27+.
AUS 27969 was crossed with the susceptible genotype Avocet S (AvS) and the distribution of F3
lines conformed to monogenic segregation [40 non-segregating resistant (NSR), 93 segregating
(Seg), and 37 non-segregating susceptible (NSS); χ2 = 1.61, P2d.f. >0.05] when tested with the same
pathotype at the seedling stage. The population is currently being selfed to F6. DNA from NSR
and NSS lines will be sent for high throughput analysis to identify the genomic region carrying the
resistance gene. Resistance-linked SNPs will be mapped on the F6 RIL population. The resistance
gene will be backcrossed into modern Australian wheat backgrounds.
