YIELD REACTIONS AND RATES OF ORIGIN OF CHROMOSOME REARRANGEMENTS AND GENE MUTATIONS IN BARLEY

ENETIC changes in diploid barley, induced by the application of G various mutagens (EHRENBERG et al., 1959(EHRENBERG et al., , 1961;;GUSTAFSSON, 1963 GUSTAFSSON, , 1965)), comprise structural chromosome rearrangements, gene mutations and extranuclear mutations.The viability reactions (including productivity and competitive ability) have been continually studied for mutations of various kinds, ranging from lethal gene mutations to fully productive mutants, under different modes of cultivation, in the homozygous and heterozygous state.Some 15 years ago work was started testing the productivity of homozygous translocations (NYBOM, 1954(NYBOM, , 1956;; GUSTAFSSON and TEDIN, 1954).In recent years these tests have been intensified and extended to cover also honiozygous chromosome inversions.Phytotron studies of induced mutants have recently been undertaken.Some results will be published shortly.A problem of special importance in this connection deals with the relative rates of origin of various genetic changes, especially of those possessing an unchanged or increased productivity. YIELDING ABILITY OF CHROMOSOME TRANSLOCATIONS AND INVERSIONSOnly data from 1964 and 1965 will be briefly discussed here.The translocation and inversion materials of these two years comprise the following series of testing: