Evaluation of marker-assisted selection for the stripe rust resistance geneYr15, introgressed from wild emmer wheat.
Stripe rust disease is caused by the fungusPuccinia striiformisf. sp.triticiand severely threatens wheat worldwide, repeatedly breaking resistance conferred by resistance genes and evolving more aggressive strains. Wild emmer wheat,Triticum dicoccoides, is an important source for novel stripe rust resistance (Yr) genes.Yr15, a major gene located on chromosome 1BS ofT. dicoccoides, was previously reported to confer resistance to a broad spectrum of stripe rust isolates, at both seedling and adult plant stages. Introgressions ofYr15into cultivatedT. aestivumbread wheat andT. durumpasta wheat that began in the 1980s are widely used. In the present study, we aimed to validate SSR markers from theYr15region as efficient tools for marker-assisted selection (MAS) for introgression ofYr15into wheat and to compare the outcome of gene introgression by MAS and by conventional phenotypic selection. Our findings establish the validity of MAS for introgression ofYr15into wheat. We show that the size of the introgressed segment, defined by flanking markers, varies for both phenotypic selection and MAS. The genetic distance of the MAS marker fromYr15and the number of backcross steps were the main factors affecting the length of the introgressed donor segments. MarkersXbarc8andXgwm493, which are the nearest flanking markers studied, were consistent and polymorphic in all 34 introgressions reported here and are therefore the most recommended markers for the introgression ofYr15into wheat cultivars. Introgression directed by markers, rather than by phenotype, will facilitate simultaneous selection for multiple stripe rust resistant genes and will help to avoid escapees during the selection process.
Plant Genomics and Disease Resistance Laboratory, Department of Evolutionary and Environmental Biology, Institute of Evolution, Faculty of Natural Sciences, University of Haifa, Haifa, Israel.
Elitsur
E
Yaniv
Plant Genomics and Disease Resistance Laboratory, Department of Evolutionary and Environmental Biology, Institute of Evolution, Faculty of Natural Sciences, University of Haifa, Haifa, Israel.
Dina
D
Raats
Plant Genomics and Disease Resistance Laboratory, Department of Evolutionary and Environmental Biology, Institute of Evolution, Faculty of Natural Sciences, University of Haifa, Haifa, Israel.
Yefim
Y
Ronin
Plant Genomics and Disease Resistance Laboratory, Department of Evolutionary and Environmental Biology, Institute of Evolution, Faculty of Natural Sciences, University of Haifa, Haifa, Israel.
Abraham B
AB
Korol
Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel.
Adriana
A
Grama
Department of Plant and Food Sciences, University of Sydney, Sydney, Australia.
Harbans
H
Bariana
Department of Plant Sciences, University of California, Davis, CA, USA.
Jorge
J
Dubcovsky
LUKE/BI Plant Genomics Lab, Institute of Biotechnology, Viikki Biocenter, University of Helsinki, P.O. Box 65, Helsinki, Finland.
Alan H
AH
Schulman
Linkage drag; Marker-assisted selection (MAS); Puccinia striiformis f. sp. tritici; Simple sequence repeats (SSRs); Triticum aestivum; Triticum dicoccoides; Triticum durum