Assessment of molecular markers and marker-assisted selection for drought tolerance in barley (Hordeum vulgare L.)
Akmaral Baidyussen, Gulmira Khassanova, Maral Utebayev, Satyvaldy Jatayev, Rystay Kushanova, Sholpan Khalbayeva, Aigul Amangeldiyeva, Raushan Yerzhebayeva, Kulpash Bulatova, Carly Schramm, Peter Anderson, Colin L. D. Jenkins, Kathleen L. Soole, Yuri Shavrukov
Abstract
The present status in the field of molecular markers and Marker-assisted selection (MAS), using the example of drought tolerance in barley, has been updated in this review. The accuracy of selected QTLs, candidate genes and suggested markers was assessed in the barley genome cv. Morex. Six common strategies are described for molecular marker development, candidate gene identification and verification, and their possible application in MAS to improve grain yield and yield components in barley under drought stress. These strategies are based on the following statements: (1) Molecular markers designated as genomic ‘tags’, and their ‘prediction’ is strongly dependent on their distance, on genetic or physical maps, from a candidate gene; (2) plants react differently under favourable and stressful conditions or depending on their stage of development; (3) each candidate gene must be verified by confirming their expression in the relevant conditions, e.g. drought; (4) the molecular marker identified must be validated for MAS for tolerance to drought stress and improved grain yield; (5) the small number of molecular markers realized for MAS in breeding, from the huge amount of studies targeting candidate genes, can be explained by the complex nature of drought stress, and multiple stress-responsive genes in each barley genotype that are expressed differentially depending on many factors.