Adaptation to environment in diploid barley: from quantitatively inherited traits, to QTLs and genes ?

In the last few decades Quantitative Trait Loci (QTL) mapping represented a breakthrough for the study of quantitatively inherited traits. Since then, substantial parts of phenotypic variation for crucial traits in crops have been found as explained by a limited to medium number of loci. Among the most important traits studied by QTL mapping, adaptation to the environment was dissected in its main genetic components. One of the species where the highest significant advances in understanding the genetic architecture of environmental adaptation have been made is the diploid barley in the tribe of Triticeae. An overview will be presented about discovery of genetic bases of such quantitative traits in barley, like regulation of flowering time and tolerance to abiotic stresses, till the identification of several candidate genes. Open questions remain about the past, present and expected future success in molecular breeding for QTL marker- and genomic-assisted selection. By reviewing such aspects, examples about QTL sensitivities to environmental variables will be done. Other questions remain about the biological interpretation of quantitative traits in the "omic" era, in particular for the adaptation to the environment. An overview of recent results in this field will be done, with examples about impact of copy number variation (CNV) on phenotype.