Describing and Mapping ROOT Mutants in Barley

The interest in producing and exploiting mutant collections has recently increased due to the availability of new genomics-assisted approaches which can help in streamlining forward genetics studies. Surprisingly, no comprehensive compendium or collection of root mutants is available for the Triticeae. In this context, we are performing a forward-genetics screening of a barley mutagenized population  which was produced in the genetic background of the cultivar ‘Morex’ (Talamè et al. 2008, PBJ 6:477-485), aiming to identify root morphology mutants. We have already analyzed >3,000 M5 mutant families at the seedling stage and several tens of root mutants have been identified and grouped into three categories: root growth rate/length (77%), root morphology (15%) and root hairs (8%). Mendelian inheritance was checked for randomly chosen mutants by outcrossing the mutants to a different cultivar. Pleiotropic effects of root mutants on shoot traits were apparently low although additional tests are undergoing. Three mutants were genetically mapped by means of a SNP array (Illumina 9K)-based bulk-segregant analysis and are being further analyzed by NGS-based approaches. Final objective of this work is to develop analytical protocols enabling to make our mutant population a generally useful resource for forward functional genomics in barley.