Adult plant and seedling resistance to powdery mildew in a Triticum aestivum × Triticum militinae hybrid line

Abstract

In the progeny of a cross between the common wheat cultivar Tähti and Triticum militinae, a member of the timopheevii group of tetraploid wheats, several hybrid lines were selected that are characterized by improved seedling and adult plant resistance (APR) to powdery mildew. An F2 single-seed descendant mapping population segregating for seedling resistance and APR to powdery mildew was analysed for the identification of quantitative trait loci (QTL). The main QTL responsible for APR was detected on the long arm of chromosome 4A tightly linked to the Xgwm160 locus on a T. militinae translocation explaining up to 54% of phenotypic variance. The same translocation influenced seedling resistance to powdery mildew upon inoculation of plants with a synthetic population of Blumeria graminis DC. f. sp. tritici, and explained 28-33% of the phenotypic variance.

Estimation of genetic parameters and prediction of breeding values for apple fruit-quality traits using pedigreed plant material in Europe

“…On chromosome 4B, a QTL was detected at the top of our linkage group and could correspond to one of the QTL detected on chromosome 4B by Börner et al (2002). On chromosome 5A, a QTL was detected in the second interval of the first linkage group, and could correspond to one of the QTL detected in Triticum militinae by Jakobson et al (2006). On chromosome 5B, a QTL was detected near marker Xgwm499 and could be similar to the QTL detected in Triticum militinae by Jakobson et al (2006).…”

“…On chromosome 5A, a QTL was detected in the second interval of the first linkage group, and could correspond to one of the QTL detected in Triticum militinae by Jakobson et al (2006). On chromosome 5B, a QTL was detected near marker Xgwm499 and could be similar to the QTL detected in Triticum militinae by Jakobson et al (2006). On chromosome 7A, as discussed previously, one of the QTL detected in the RIL population could correspond to the QTL detected near the marker Xgwm344 in the F 2:3 mapping population by Chantret et al (2001).…”

“…During the past 10 years, several studies on the genetic control of APR to powdery mildew were carried out in several wheat lines, including the Swiss cultivar Forno , the US' cultivar Massey and its derivatives (Liu et al 2001;Tucker et al 2006), the spring variety Opata 85 and the synthetic wheat W7984 (Börner et al 2002), the French breeder lines RE714 (Chantret et al 2001;Mingeot et al 2002) and RE9001 (Bougot et al 2006), the Japanese cultivar Fukuho-komugi (Liang et al 2006), a T. militinae introgression line (Jakobson et al 2006) and the CYMMIT cultivar Saar (Lillemo et al 2008). In these studies, 3-18 QTL were identified, among which between one and three were consistent across environments.…”

Fine mapping, phenotypic characterization and validation of non-race-specific resistance to powdery mildew in a wheat–Triticum militinae introgression line

“…In our previous study, we described APR to powdery mildew transferred into bread wheat from T. militinae (Jakobson et al 2006). The resistant introgression line 8.1 derived from a cross between T. aestivum and T. militinae exhibited effective APR in field tests and showed full resistance to a mix of B. graminis test isolates (races) at the seedling stage.…”

“…In addition to the QPm.tut-4A QTL, minor QTLs for seedling resistance and/or APR were located on chromosomes 1A, 2A, 5A, 1B and 5B on a suggestive level (LOD \1.0-1.5) (Jakobson et al 2006). As qualitative resistance genes Pm3, Pm4 and Pm16 were mapped in the regions of suggestive minor QTL on chromosomes 1A, 2A and 5B, respectively (Huang and Röder 2004;Chen et al 2005), the observed seedling resistance might have been a result of pyramidizing of a set of race-specific Pm genes in the line 8.1, with each of the QTL being responsible for resistance to a subset of Bgt isolates in the tested artificial mix.…”