Introgression Of Mutant Alleles In Barley

The IAEA has a mandate of “Atoms for Peace” and this involves the development of useful mutants for plant breeding to safeguard food security. Mutants are commonly induced in contemporary materials for target traits (yield, quality, disease resistance, tolerance to abiotic stresses, etc.). Desired mutants may be detected using high-throughput phenotyping and genotyping. Mutation breeding has been successful in producing 3218 officially released mutant varieties in 224 species (http://mvgs.iaea.org/). Future strategies involve utilization of the vast array of existing mutants and rapid introgression methods to place desired alleles in elite breeding materials. In barley (Hordeum vulgare) over 1,000 mutant genes have been catalogued and over 800 have been backcrossed into one common parent, the Bowman backcross-derived lines (BBLs). The BBLs are utilized in studying the effects of mutant alleles and have huge potential for crop improvement. BBLs with specific genes or gene combinations can be crossed with contemporary breeding lines from a target environment/Member State and the progeny backcrossed repeatedly to the recipient lines. By using small pots, continuous lighting and embryo culture, 3–4 generations can be obtained per year. In two years BC6 lines may be achieved. However, lines carrying more than 90% of the genetic background from the recurrent parent and the mutant allele(s) of interest can be selected earlier. This pre-breeding strategy facilitates the transfer of desired mutant alleles into the breeding programmes of Member States. An example of on-going work is the fodder barley trait mutants Kap1 (hooded, awnless) and rob1 (orange lemma, low lignin).