Barley is among the oldest domesticated crops, tolerant to various abiotic stresses. During domestication, the genetic diversity and adaptability of barley consistently decreased due to the limited number of genotypes included in the selection, therefore, increasing the genetic diversity is one of the priorities of breeding. Many modern varieties were created using spontaneous or induced mutants, which are important not only from a practical but also from a forward genetics point of view enabling the localisation of genes and determining their functions. The yield of cereals is directly related to the structure of reproductive systems, so the identification of genes involved in their development is relevant for targeted improvement of yield. Among the barley mutants, at least three groups of non-allelic tweaky-type mutants of independent origin are known, all possessing disturbed spike development and an unstable number of floral organs. During the doctoral project, the F3 mapping populations of non-allelic tweaky and missing kernel and tweaky N18 mutants will be created and used for mapping of mutant loci using whole genome sequencing. Validation, functions and potential targets of regulation of the localized candidate genes will be determined by comparison of the transcriptome profiles of CRISPR-cas9-induced knock-outs in the WT plants.