The search for QTL in barley (Hordeum vulgare L.) using a new mapping population

Ninety-nine different lines of the Doubled-Haploid F2 winter barley population W766 ('Angora' x 'W704/137') were genetically fingerprinted using AFLP, microsatellite, morphological and resistance markers. A preliminary map consisting of seven linkage groups is presented. The map contains a highly distorted region on the long arm of chromosome 3H reflecting preselection of the genotypes for resistance against barley mild mosaic virus. QTL analysis of morphological and phenological traits yielded 99 significant QTL, with most traits (66.3%) being represented by a single QTL. The distribution of significant QTL over the chromosomes was very uneven, the bulk being placed on the long arm of chromosome 3H and no QTL being found on chromosome 4H. This possibly points to the presence of a strong pleiotropic gene on 3H or of a group of related genes that mask weaker effects that were found on other linkage groups as subsignificant QTL. Using two examples of detected QTL (for tillering and grain number), it is shown how the findings of the QTL analysis could be incorporated into an existing morphological simulation model of barley using simple statistical methods.