THE EFFECT OF SELECTION FOR PROTEIN AND ISOZYME LOCI ON QUANTITATIVE TRAITS IN A DOUBLED HAPLOID POPULATION OF BARLEY

Doubled haploid families extracted from the Ft hybrid of the spring barley cross (Dissa × Sabarlis) by the Hordeum bulbosum technique were scored for the segregation of alleles at isozyme loci. Isozyme and protein loci on all seven pairs of barley chromosomes were examined and five out of the seven pairs of barley chromosomes (21, 31, 41, 61 and 71) were shown to possess polymorphic isozyme and protein loci. The systems tested did not deviate significantly from the expected 1:1 ratio and esterase loci on chromosome 3 were mapped intra-chromosomally. The relationship between marker loci and quantitative trait loci (QTL) was examined. A comparison of the mean scores for each allelic class revealed significant differences in the expression of a range of quantitative traits. Thus, by selecting for isozyme and protein phenotypes one can significantly affect the expression of certain QTL in barley. For example, allelic variation at the a-Amy-1 locus makes a large contribution to the genetic variation available for selection in the case of single plant yield. The advantage of using DH families for gene mapping and in dissecting QTL are discussed. © 1990 The Genetical Society of Great Britain.