THE BARLEY GENOME AND ITS RELATIONSHIP WITH THE WHEAT GENOMES - A SURVEY WITH AN INTERNATIONALLY AGREED RECOMMENDATION FOR BARLEY CHROMOSOME NOMENCLATURE

The paper reviews recent literature on the cytology, cytogenetics, mol ecular cytogenetics, and gene structure of barley, and on the relation ship of the barley and wheat genomes. The. information collected demon strates largely similar genetic contents and collinearity of gene loci in the seven chromosomes of barley and in those of other members of t he Triticeae. The high level of synteny indicates that the whole group can be considered as a single gene pool. On this basis, the 7th Inter national Barley Genetics Symposium recommended that (i) the currently used designations of the barley chromosomes (the BURNHAM and HAGBERG s ystem) should become secondary to the use of the Triticeae system; i.e ., each of the seven barley chromosomes is designated by a numeral bet ween 1 and 7 according to its homoeologous relationship with the chrom osomes of the wheat genomes followed by the genomic symbol H, e.g., 2H ; (ii) the genomes of Hordeum vulgare and H. bulbosum are symbolized w ith the letter H; and (iii) the arms of the barley chromosomes are des ignated by the capital letters S and L (cf. SINGH and TSUCHIYA 1982b). Further, it was recommended that the barley genome present in the bar ley cultivar 'Betzes' should become the reference genome in the Tritic eae.