The hard red spring wheat cultivar AC Domain and the Canada Prairie Sp
ring wheat AC Taber have recently been licensed and released in wester
n Canada and are resistant to leaf rust caused by Puccinia recondita f
. sp. tritici. To determine the genetic basis of this resistance, the
two cultivars were crossed with the leaf rust susceptible wheat Thatch
er (Tc), and F-1 plants were backcrossed to Thatcher. F-2 families fro
m Tc2/AC Domain and AC Taber/Tc*2 were tested with isolates of P. rec
ondita f. sp. tritici as seedlings in the greenhouse and as adults in
the field rust nursery. Segregation of BC1F2 families indicated that A
C Domain had seedling resistance genes Lr10 and Lr16, and the adult pl
ant gene Lr34. AC Domain was also hypothesized to have the adult plant
gene Lr12 based on infection types with I! recondita f. sp. tritici i
solates that differed for virulence to Lr12. The effective field leaf
rust resistance of AC Domain was conditioned by Lr16 and Lr34. Segrega
tion of BC1F2 families and infection types of BC1F3-derived BC1F4 plan
ts indicated that AC Taber had Lr14a for seedling resistance, the adul
t plant gene Lr13, plus an additional uncharacterized adult plant resi
stance gene currently designated as LrTb.