QTug.sau-3B is a major quantitative trait locus for wheat hexaploidization.
Bottom Line: Meiotic nonreduction resulting in unreduced gametes is thought to be the predominant mechanism underlying allopolyploid formation in plants.Comparative genome analysis indicated that this QTL was close to Ttam-3B, a collinear homolog of tam in wheat.Although the relationship between QTug.sau-3B and Ttam requires further study, high frequencies of unreduced gametes may be related to reduced expression of Ttam in wheat.
Affiliation: Triticeae Research Institute, Sichuan Agricultural University at Chengdu, Wenjiang, Sichuan 611130, People's Republic of China.Show MeSH
Mentions: To further investigate the genetic basis of the high capacity of hexaploidization in LDN, haploid (triploid) population SynH1 (LDN/AS313//AS60) and its corresponding doubled haploid (hexaploid) population SynDH1 were used for QTL mapping (Figure 1). The molecular map constructed by the two populations should be the same, although the ploidy of the populations was different. The molecular data for the 113 SynDH1 lines were used to construct a linkage map containing 588 molecular markers that had been assigned to the 14 A-genome and B-genome chromosomes, covering a total genetic distance of 2,048.79 cM, with a mean distance of 3.48 cM between adjacent markers (Zhang et al. 2012). The selfed seed set rates of the SynH1 plants were used as phenotypic data for QTL analysis. The seed set rates on the triploid hybrid plants varied from 0.07 to 0.72, with an average of 0.33 (Figure 6A). QTL analysis detected a major QTL for selfed seed level on chromosome 3B, between markers Xgwm285 and Xcfp1012, with a logarithm of odds (LOD) score of 10.0 (Figure 6B). No segregation distortion was detected for the two markers with a genetic distance of 1 cM (Table S2; Figure 6B). Both markers are located in deletion bin 3BS5-0.07-0.33 (Paux et al. 2008). This QTL explained 29.8% of the phenotypic variance. The allele from LDN showed a positively additive effect and was responsible for the high frequency of genome doubling in hybrids. Besides this major QTL, we detected a weaker QTL between Xgwm526 and wPt-7175 on 2A chromosome with a LOD score of 3.4 and explained 8.7% of the phenotypic variance. However, the two markers covered a long genetic distance of 46.33 cM. We did not further analyze this QTL.
Affiliation: Triticeae Research Institute, Sichuan Agricultural University at Chengdu, Wenjiang, Sichuan 611130, People's Republic of China.