title: Wheat Landrace Genome Diversity.
abstract: Understanding the genomic complexity of bread wheat (Triticum aestivumL.) is a cornerstone in the quest to unravel the processes of domestication and the following adaptation of domesticated wheat to a wide variety of environments across the globe. Additionally, it is of importance for future improvement of the crop, particularly in the light of climate change. Focusing on the adaptation after domestication, a nested association mapping (NAM) panel of 60 segregating biparental populations was developed, mainly involving landrace accessions from the core set of the Watkins hexaploid wheat collection optimized for genetic diversity. A modern spring elite variety, "Paragon," was used as common reference parent. Genetic maps were constructed following identical rules to make them comparable. In total, 1611 linkage groups were identified, based on recombination from an estimated 126,300 crossover events over the whole NAM panel. A consensus map, named landrace consensus map (LRC), was constructed and contained 2498 genetic loci. These newly developed genetics tools were used to investigate the rules underlying genome fluidity or rigidity,e.g., by comparing marker distances and marker orders. In general, marker order was highly correlated, which provides support for strong synteny between bread wheat accessions. However, many exceptional cases of incongruent linkage groups and increased marker distances were also found. Segregation distortion was detected for many markers, sometimes as hot spots present in different populations. Furthermore, evidence for translocations in at least 36 of the maps was found. These translocations fell, in general, into many different translocation classes, but a few translocation classes were found in several accessions, the most frequent one being the well-known T5B:7B translocation. Loci involved in recombination rate, which is an interesting trait for plant breeding, were identified by QTL analyses using the crossover counts as a trait. In total, 114 significant QTL were detected, nearly half of them with increasing effect from the nonreference parents.
authors.affiliation: Crop Genetics, John Innes Centre, Norwich NR4 7UH, UK luzie.wingen@jic.ac.uk.
authors.forename: Luzie U
authors.identifier: 0000-0002-4682-4764
authors.initials: LU
authors.lastname: Wingen
authors.affiliation: Crop Genetics, John Innes Centre, Norwich NR4 7UH, UK.
authors.forename: Claire
authors.initials: C
authors.lastname: West
authors.affiliation: Crop Genetics, John Innes Centre, Norwich NR4 7UH, UK.
authors.forename: Michelle
authors.initials: M
authors.lastname: Leverington-Waite
authors.affiliation: Crop Genetics, John Innes Centre, Norwich NR4 7UH, UK.
authors.forename: Sarah
authors.initials: S
authors.lastname: Collier
authors.affiliation: Crop Genetics, John Innes Centre, Norwich NR4 7UH, UK.
authors.forename: Simon
authors.initials: S
authors.lastname: Orford
authors.affiliation: Crop Genetics, John Innes Centre, Norwich NR4 7UH, UK.
authors.forename: Richard
authors.initials: R
authors.lastname: Goram
authors.affiliation: Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, UK.
authors.forename: Cai-Yun
authors.initials: CY
authors.lastname: Yang
authors.affiliation: Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, UK.
authors.forename: Julie
authors.initials: J
authors.lastname: King
authors.affiliation: Life Sciences, University of Bristol, BS8 1TQ, UK.
authors.forename: Alexandra M
authors.initials: AM
authors.lastname: Allen
authors.affiliation: Life Sciences, University of Bristol, BS8 1TQ, UK.
authors.forename: Amanda
authors.initials: A
authors.lastname: Burridge
authors.affiliation: Life Sciences, University of Bristol, BS8 1TQ, UK.
authors.forename: Keith J
authors.initials: KJ
authors.lastname: Edwards
authors.affiliation: Crop Genetics, John Innes Centre, Norwich NR4 7UH, UK.
authors.forename: Simon
authors.initials: S
authors.lastname: Griffiths
mesh_terms: D019143:Evolution, Molecular; D008040:Genetic Linkage; D018745:Genome, Plant; D011110:Polymorphism, Genetic; D040641:Quantitative Trait Loci; D014908:Triticum / Q000235:genetics*
keywords: map distance; marker order; nested association mapping; recombination QTL; segregation distortion; translocation