Abstract
Three doubled haploid lines artificially derived from each of the burley tobacco varieties, Burley 21, Ky 10, and Harrow Velvet, were compared with the normal diploid lines in 1971. Some of the doubled haploid lines were gene-tically different from the normal diploid lines. At least, three out of the nine doubled hap-loid lines showed the reduced vigor, resulting in the lower yield than the normal diploids. However, none of the doubled haploid lines was higher than the normal diploids in yield. An experimental line, DH-6, derived from Ky 10 variety had an apparently higher leaf number than that of the parental variety. These results were ascertained by the experi-ments in the next year. From the comparison of clonally related doubled haploid lines, it was assumed that the genetic variation among the entries was due to the mutation occurred in haploid stage.
