Mapping genes for callus growth and shoot regeneration in barley (Hordeum vulgare L.)

The quantitative trait loci (QTLs) controlling callus growth and subsequent shoot regeneration were identified by 222 markers in doubled haploid (DH) lines derived from the cross between Steptoe x Morex in barley (Hordeum vulgare L.). The DH lines showed a wide and continuous variation in these two tissue culture traits, and the transgressive segregation was observed for the shoot regeneration rate among the DH lines. The interval mapping analysis revealed that callus growth and shoot regeneration ability were controlled by multiple genes and the position of individual genes was different each other. Morex contributed two QTLs for callus growth tentatively named Qcg 1 and Qcg 2. Steptoe contributed three QTLs for shoot regeneration named Qsr 1, Qsr 2, and Qsr 3, while Morex contributed a QTL for shoot regeneration named Qsr 4. In the multiple genie model, two QTLs for callus growth and four QTLs for shoot regeneration accounted for 47.8 % and 49.8 % of the total variation in the population, respectively. These findings indicated that lines with high regeneration ability could be selected by pyramiding the multiple genes controlling high regeneration ability.