Molecular Mapping of Non-Brittle Rachis Genes btr1 and btr2 using STS Markers in Barley

Abstract

Brittle rachis is an important trait to study the domestication process in barley. Ancient farmers preferred to have non-brittle barley for cultivation, and domesticated barley lost the brittle rachis after a process of human selection. In this study, partial linkage maps in the region of non-brittle rachis genes btr1 and btr2 were constructed using two wild × cultivar F₂ populations. STS markers derived from AFLP markers e09m25-08, e30m07-09 and e50m21-01, which showed no recombination with the btr1 and btr2 loci in recombinant inbred lines (RILs), showed recombination with the btr1 and btr2 loci in the two F₂ populations. Though there were few differences in map distances, orders of the markers were highly conserved. OUH602 (wild) × Kanto Nakate Gold (cultivar) was suitable for highresolution mapping of the btr1 locus due to unambiguous phenotypes in segregating F₂ plants.