High genetic diversity of Spanish common wheats as judged from gliadin alleles

Gliadin alleles were identified in 100 common wheat cultivars registered an d/or grown in Spain during the last 40 years. A very high level of genetic polymorphism was found: in total, 103 allelic variants including one nuli-a llele were found at the six major Gli loci in the Spanish wheats studied. A n average genetic diversity for these six loci was found to be higher (H = 0.844) than in any group of wheat cultivars studied previously. Spanish whe ats bred in Spain demonstrated even higher genetic diversity (H = 0.868), p robably because of the occurrence in this group of some landraces (local va rieties) assumed to be strongly differentiated to fit local environments. T he high level of genetic diversity of wheats grown in Spain was maintained by the introduction of distantly related wheat germplasm from different sou rces, especially from Italy and CIMMYT. A slight decrease of genetic divers ity in recently registered cultivars might be caused by the excessive intro duction of French wheats. Thirteen new alleles found in Spanish wheats were catalogued, including Gli-D2w which encodes the first Gli-D2-controlled ga mma-gliadin to be found.