Genetic map of Triticum turgidumbased on a hexaploid wheat population without genetic recombination for D genome

Li Zhang,Ming Hao,Bo Zhang,Ya-Xi Liu,Chun-Ji Liu,Jiang-Tao Luo,Huai-Gang Zhang,Bao-Long Liu,You-Liang Zheng,Deng-Cai Liu,Zhong-Wei Yuan,Ze-Hong Yan,Lian-Quan Zhang

doi:10.1186/1471-2156-13-69

Abstract

BackgroundA synthetic doubled-haploid hexaploid wheat population, SynDH1, derived from the spontaneous chromosome doubling of triploid F1 hybrid plants obtained from the cross of hybrids Triticum turgidum ssp. durum line Langdon (LDN) and ssp. turgidum line AS313, with Aegilops tauschii ssp. tauschii accession AS60, was previously constructed. SynDH1 is a tetraploidization-hexaploid doubled haploid (DH) population because it contains recombinant A and B chromosomes from two different T. turgidum genotypes, while all the D chromosomes from Ae. tauschii are homogenous across the whole population. This paper reports the construction of a genetic map using this population.ResultsOf the 606 markers used to assemble the genetic map, 588 (97%) were assigned to linkage groups. These included 513 Diversity Arrays Technology (DArT) markers, 72 simple sequence repeat (SSR), one insertion site-based polymorphism (ISBP), and two high-molecular-weight glutenin subunit (HMW-GS) markers. These markers were assigned to the 14 chromosomes, covering 2048.79 cM, with a mean distance of 3.48 cM between adjacent markers. This map showed good coverage of the A and B genome chromosomes, apart from 3A, 5A, 6A, and 4B. Compared with previously reported maps, most shared markers showed highly consistent orders. This map was successfully used to identify five quantitative trait loci (QTL), including two for spikelet number on chromosomes 7A and 5B, two for spike length on 7A and 3B, and one for 1000-grain weight on 4B. However, differences in crossability QTL between the two T. turgidum parents may explain the segregation distortion regions on chromosomes 1A, 3B, and 6B.ConclusionsA genetic map of T. turgidum including 588 markers was constructed using a synthetic doubled haploid (SynDH) hexaploid wheat population. Five QTLs for three agronomic traits were identified from this population. However, more markers are needed to increase the density and resolution of this map in the future study.

Highlights

A synthetic doubled-haploid hexaploid wheat population, SynDH1, derived from the spontaneous chromosome doubling of triploid F1 hybrid plants obtained from the cross of hybrids Triticum turgidum ssp. durum line Langdon (LDN) and ssp. turgidum line AS313, with Aegilops tauschii ssp. tauschii accession AS60, was previously constructed
The objectives of this study were to (i) develop a genetic map of the A and B genomes based on DArT (Diversity Arrays Technology), simple sequence repeat (SSR), insertion site-based polymorphism (ISBP), and highmolecular-weight glutenin subunit (HMW-GS) markers using a tetraploidization-hexaploid synthetic doubled haploid (SynDH) population, (ii) assess the extent of segregation distortion, (iii) evaluate the quality of linkage maps constructed using this strategy by comparing with previously reported maps, and (iv) identify quantitative trait locus (QTL) in this population
Construction of genetic map and QTL analysis this SynDH population was derived from the cross of three parents (LDN/AS313//AS60), all of the D chromosomes came from the single genotype AS60

Summary

Introduction

A synthetic doubled-haploid hexaploid wheat population, SynDH1, derived from the spontaneous chromosome doubling of triploid F1 hybrid plants obtained from the cross of hybrids Triticum turgidum ssp. durum line Langdon (LDN) and ssp. turgidum line AS313, with Aegilops tauschii ssp. tauschii accession AS60, was previously constructed. SynDH1 is a tetraploidization-hexaploid doubled haploid (DH) population because it contains recombinant A and B chromosomes from two different T. turgidum genotypes, while all the D chromosomes from Ae. tauschii are homogenous across the whole population. This paper reports the construction of a genetic map using this population. Many important crops such as bread wheat, durum wheat, cotton, oat, coffee, and tobacco are allopolyploids. They originated from the merger of two or more distinct but related genomes, by interspecific hybridization and genome doubling. Genetic populations with the same ploidy level as a given crop are needed to analyze ancestral genes for crop improvement; their construction is labor-intensive and timeconsuming

Objectives

Methods

Results

Discussion

Conclusion