A Combination of Three Genomic Regions Conditions High Level of Adult Plant Stripe Rust Resistance in Australian Wheat Cultivar Sentinel.

A seedling susceptible Australian common wheat cultivar Sentinel showed resistance to stripe rust under field conditions. A Sentinel/Nyabing3 (Nyb3)-derived recombinant inbred line (RIL) population was phenotyped. A DArTseq marker-based linkage map of the Sentinel/Nyb3 RIL population was used to determine the chromosomal location of the adult plant stripe rust resistance possessed by Sentinel. Three consistent quantitative trait loci (QTL); QYr.sun-1BL , QYr.sun-2AS and QYr.sun-3BS were detected, and they on an average explained 18%, 15.6% and 10.6% of the variation in stripe rust response, respectively. All three QTL were contributed by Sentinel. QYr.sun-1B corresponded to the previously characterized gene Yr29 . Sentinel expressed resistance at the four-leaf stage at 21 ± 2 °C in the greenhouse. Monogenic segregation among the RIL population was observed when screened at the four-leaf stage at 21 ± 2 °C in the greenhouse, and the underlying resistance locus was temporarily named YrSen . QYr.sun-3BS peaked on YrSen . QYr.sun-2AS was mendelized by generating and phenotyping a mongenically sgregating F 6 RIL population, and it was temporarily designated YrSen2 . RILs carrying Yr29 , YrSen and YrSen2 in combination exhibited responses like the parent Sentinel. Based on a comparison of the genomic locations and resistance expression with stripe rust resistance genes previously located in their respective chromosomes, QYr.sun-2AS ( YrSen2 ) and QYr.sun-3BS ( YrSen ) were concluded to represent new loci.