Work package 2
Development of molecular markers for selection of FHB resistance at the genetic level by QTL mapping of segregating populations as well as high resolution mapping and selective genotyping of resistant germplasm
Objective:
Conventional plant breeding utilizes the phenotypic selection of superior plants or plant families. Novel technologies allow to select directly on the DNA level. We aim to identify user friendly DNA markers, preferably co-dominant PCR assays, which tag the genomic regions of wheat coding for major genes (QTLs) conferring resistance to FHB. We will develop molecular markers for at least three diverse resistance sources: from Asia (Sumei3), South-America (Frontana) and Europe (Arina). The availability of DNA markers would open the way for marker assisted selection for FHB resistance in early generations. Marker assisted back-crossing will then be feasible and will allow rapid introduction of exotic resistance genes into adapted European germplasm. We will furthermore evaluate genetic diversity, as revealed by DNA markers, among resistant wheat stocks. Such information will help the breeders to combine complementary and new sources of resistance against FHB.
Description
of work:
Genomic regions conferring resistance to FHB will be characterized in
diverse wheat sources by means of several complementary molecular marker
approaches.
Quantitative trait loci (QTL) influencing FHB resistance will be detected
by evaluation of segregating populations for FHB resistance in replicated
field trials (link to WP1). Genotypic evaluation will be performed by RFLP,
AFLP, SSR and other markers. Markers for candidate genes will be integrated
upon availability (link to WP3). Markers with linkage to FHB resistance traits
will be identified by QTL analysis.
In one segregating population two QTL for FHBR were already identified on
chromosomes 3BS and 5AS respectively. Second generation mapping populations
will be created segregating for single QTL and the promising chromosomal
segments saturated with DNA markers, as in ST1.
Wheat germplasm from diverse sources (up to 100 lines) will be evaluated for FHBR (see WP1) and screened for genetic diversity using DNA polymorphisms. We will focus on SSR markers, with linkage to known QTL regions and determine allelic variation for promising candidate resistance genes (link to WP3).