SEX MOLECULAR MARKERS REVEAL DIFFERENCES OF Y-CHROMOSOME MOLECULAR STRUCTURE AMONG HOPS OF EUROPEAN AND AMERICAN ORIGIN
Hop, Humulus lupulus L., is a dioecious plant (2n=2x=20) with two heteromorphic sex chromosomes X and Y. The Y chromosomes of Native American and European male hops are morphologically different. Identification of sex is a common step in hop breeding. Molecular markers would allow detecting male hop plants at the seedling stage. We tested three presumed male-specific STS molecular markers on 66 male hop plants of American and European origin: one marker developed on the basis of RAPD analysis with hop individuals of German origin and two markers developed on the basis of ISSR analysis on hops of Russian origin. About half of the male plants including males from Germany and Russia were detected by all three markers. The other male plants were not detected by the RAPD-based marker, while the two ISSR-based markers produced unexpected but reproducible major bands in these genotypes. Cluster analysis divided the male plants into two groups depending on the male ancestor. Male plants detected by all three STS markers are presumed to have Y chromosomes that originated from European hops. All of the original 66 male plants were again tested by ISSR PCR. The STS-undetected males had no male specific bands while all STS-detected males produced ISSR bands regardless of their pedigree. Based upon this information there appears to be differences between hops of two origins in the distribution of simple repeats in the DNA of Y-chromosomes. The RAPD-derived STS also appears specific for Y-chromosome of males originating in Europe.
Danilova, T.V. and Henning, J.A. (2005). SEX MOLECULAR MARKERS REVEAL DIFFERENCES OF Y-CHROMOSOME MOLECULAR STRUCTURE AMONG HOPS OF EUROPEAN AND AMERICAN ORIGIN. Acta Hortic. 668, 85-92
Humulus lupulus, identification, RAPD, ISSR, STS markers