RECENT BARLEY MUTANTS AND THEIR LINKAGES II. GENETIC DATA FOR FURTHER MUTANTS

Introduction In this report data are presented from linltage studies of a group of mutants and genetic stoclts assembled at the University of Alberta. Some of the results have been described briefly in prelinlinary reports (Wallter, Kasha and Miller, 1958; Wallter and i\/liller, 1958). Others are from a continuation of the study of eight mutants reported in the first article of this series (Kasha and Wallter, 1960). T h e remainder are from studies to attempt a further delineation of the l inl ta~e ~ r o u p on chromosome 6. a. S ~nce these studies are part of a larger project \vl~ose prin~ary objective is the production of ~nultiple recombinants, it has not usually been possible to carry out the additional studies that would be necessary to establish the location of the mutant genes on the linltage maps. This information will be sought during the course of further recombination of the mutant and recessive rnarlter alleles within each of the linltage groups. The characters described are those for which indications of linltage were e~lcountered in these studies. T h e descriptions and independence data for a further group that has not yet sh0u.n linltage have been reserved for future reports. Methods Crosses were verforined after hand-emasculation and. to eliminate the DOSsibilitv of accidenial selfinp. F , ~ l a n t s were checlted for tl;e presence of d o k n U' 1 ant genes received from the pollen parents. Variegated ndtants were used as pollen parents of crosses, to avoid the possibility of cytoplasn~ic transmission of variegation through the egg. The progenies of individual FI plants f rom crosses involving mutants maintainable only through heterozygotes (malesterile-10) were grown in separate plots, and only those segregating for the mutant character xvere classified for linltage analysis. T h e F,'s were field-planted with a modified V-belt seeder, designed by J. Fitzsin~mons, Parkland Farm, University of Alberta, that gave a regular spacing of sinple lternels but did not ~ e r m i t ' t h e detection of permination failures. u. U Progenies segregating for c111ord~l1~11 mutants were classified at both the seedling and the heading stage and the mutant plants were marked with colored tags for identification at harvest. Those progenies segregating for n~orphological foliaee characters and for s ~ i l t e characters not ex~ressed in all tillers were also U 1 I classified in the field. durinp harvest. For the analvsis of other svilte characters. u i I a single spilte was removed from each F2 plant. These spiltes were stored in inanilla bags, a separate bag for each field-classified phenotype, and were later classified for the spilte characters in the laboratory. Both F,'s and F,'s were checlted carefullv for ovule sterilitv and those F2 vrbpenies in which it occurred i J 1 U were field-classified for sterility after examining several spiltes per plant. T h e partition of i' described by Mather (1951) for obtaining the x2 value for linltage (x,,'), and the product-moment method of determining the percent-