Characterisation of Triticum vavilovii-derived stripe rust resistance using genetic, cytogenetic and molecular analyses and its marker-assisted selection.

Stripe rust resistance was identified in Triticum vavilovii( T. vaviloviiAus22498)-derived Russian wheat aphid (RWA)-resistant germplasm. Inheritance studies indicated monogenic control of resistance. The resistance gene was tentatively designated as Yrvav and was located on chromosome 1B by monosomic analysis. A close association (1.5+/-0.9% recombination) of Yrvav with a T. vavilovii-derived gliadin allele ( Gli-B1vav) placed it in chromosome arm 1BS. Yrvavwas allelic with Yr10. Tests with Yr10 avirulent and virulent pathotypes showed that Yrvav and Yr10 possess identical pathogenic specificity. Yrvav and Yr10 showed close genetic associations with alternate alleles at the Xpsp3000(microsatellite marker), Gli-B1 and Rg1 loci. Based on these observations Yrvav was named as Yr10vav. The close association between Xpsp3000 and Gli-B1 was also confirmed. The Yr10vav-linked Xpsp3000 allele (285 bp) was not present in 65 Australian cultivars, whereas seven Australian wheats lacking Yr10 carried the same Xpsp3000 allele (260 bp) as Yr10carrying wheat cultivar Moro. Xpsp3000 and/or Gli-B1 could be used in marker-assisted selection for pyramiding Yr10vavor Yr10 with other stripe rust resistance genes. Yr10vav was inherited independently of the T. vavilovii-derived RWA resistance.