The role of linkage and pleiotropy in doubled haploid lines from a barley cross

Abstract

Bjørnstad, Å. 1987. The role of linkage and pleiotropy in doubled haploid lines from a barley cross. - Hereditas 106:155–168. Lund, Sweden. ISSN 0018–0661. Received May 21, 1986 The high lysine spring barley ‘Sv73608’ is a selected B5-line from ‘Hiproly’ into ‘Mona’, with which it has been considered “isogenic”. In the present experiments it was recrossed with ‘Mona’ and doubled haploid (DH) lines produced by the Hbulbosum-method, both from F1- and F2-plants. Genetic variation was measured in 457 DH-lines in field experiments over 1 or 2 years. In 5 out of 7 quantitative characters highly significant genetic varaiation was detected contradicting the assumed “isogeneity”. In the two remaining characters, thousand grain weight and harvest index, variation was completely pleiotropic with the lys-gene. Pleiotropic effects were also present in other yield parameters (and possibly in heading date). By comparing variability in DH-lines from F1- and F2-plants indications of repulsion linkage were found in heading date, but only in one of the two years. Besides, skewed segregation ratios rendered the biometrical analysis uncertain. The evidence for coupling linkage in the case of protein content seems stronger, but only one year data are available. The utility of such analyses for doubled haploid breeding programmes is critically discussed.