Submitted to: Journal of American Society of Brewing Chemists
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/31/2003
Publication Date: 1/31/2004
Citation: Henning, J.A., Townsend, M.S., Kenny, S. 2004. Potential heterotic crosses in hops (humulus lupulus l.) as estimated by aflp-based genetic diversity and coefficient of coancestry. Journal of American Society of Brewing Chemists. 62(2):63-70. Interpretive Summary: As in other species, use of widely divergent parents in Hop (Humulus lupulus L.) hybrid crosses should result in offspring heterosis or expression of traits in the offspring that exceed that of the parents. This study was designed to determine if the genetic distance between male and female hop lines as determined by AFLP could be used as predictors for heterosis in the resulting offspring. Using AFLP, we determined genetic distance and calculated the relatedness between pairs using pedigree analysis. Genetic distance measurements were not a direct estimate of potential heterosis. However, we observed that more genetically diverse male-female pairs having genetic distance measures greater than 0.36 tended to have a greater likelihood for offspring heterosis as predicted by pedigree analysis.
Technical Abstract: As in other species, use of widely divergent parents in Hop (Humulus lupulus L.) hybrid crosses should result in offspring heterosis. The objectives were: 1) determine if genetic distance among male/female pairs (ascertained by AFLP) accurately reflects relatedness (determined by pedigree analysis), and 2) report potential heterotic crosses for hop varieties. Nineteen cultivars were analyzed for genetic distance (GD) to 82 male accessions representing the genetic diversity of the USDA Hop germplasm. GD-values ranged from 0.169 to 0.62 with an average of 0.306. For each female, ten most genetically diverse (GD > 0.36) and ten most genetically similar males (GD < 0.25) were determined and the coefficients of coancestry (COA) for each of these pairs calculated using pedigree analysis. COA-values for genetically similar pairs (COA = 0.046) were significantly higher than COA for genetically diverse pairs (COA = 0.013). Choosing Hop parents based on genetic distance may predict heterotic potential when GD is greater than 0.36.