Genetic Mapping of Gibberellic Acid-sensitive Genes for Semi-dwarfism in Durum Wheat

Semi-dwarf varieties in wheat associated with gibberellic acid (GA(3))-insensitive height reducing genes have led to significant increases in yield but often fall below this potential because of poor seedling emergence after deep showing. Alternative semi-dwarf genes may have the potential to reduce plant height without compromising early plant growth. In durum wheat, bulk segregant analysis was used to screen microsatellite markers linked with the GA(3)-sensitive genes Rht14 in cv. Castelporziano, Rht16 in cv. Edmore M1 and Rht18 in cv. Icaro. Molecular marker Xbarc3-6A for Rht14, Rht16 and Rht18 showed significant polymorphic differences among DNA bulks for height classes. The genes Rht14, Rht16 and Rht18 were linked with Xbarc3 (11.7-28.0 cM) on the short arm of chromosome 6A and they appear to be allelic. Semi-dwarf genes on chromosome 6AS may potentially be used in breeding for improved establishment.