VIEW REPORT    DOI: 10.1094/ASBCJ-62-0063

Potential Heterotic Crosses in Hops as Estimated by AFLP-Based Genetic Diversity and Coefficient of Coancestry. John A. Henning (1), USDA-ARS National Forage Seed Research Center, Oregon State University, Corvallis 97331; M. Shaun Townsend, Crop and Soil Science Department, Oregon State University, Corvallis 97331; and Steven Kenny, Crop Science Department, Washington State University-IARPAC Research Station, Prosser 99350. (1) Corresponding author. E-mail: <john.henning@orst.edu> J. Am. Soc. Brew. Chem. 62(2):63-70, 2004. Accepted October 22, 2003. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. American Society of Brewing Chemists, Inc., 2004.

Hop is a dioecious perennial with female plants grown commercially for brewing purposes. Parent selection in hop breeding on the basis of heterotic potential has not been reported in literature even though dominance has been reported in hops for several economically important traits. The objectives of this study were to determine if amplified fragment length polymorphism (AFLP)-based genetic distance among male and female accessions accurately reflect pedigree relationships and present information on potential heterotic crosses in hop. Nineteen cultivars were analyzed for genetic distance to 82 male accessions representing the assumed diversity of U.S. hops. Genetic distances (GD) between male/female pairs were estimated using AFLP (490 polymorphic bands). Distance estimates comparing males with females ranged from 0.169 to 0.62 with an overall average of 0.306. For each hop female, the 10 most genetically diverse and 10 most genetically similar males were identified and grouped. Coefficients of coancestry (COA) for each male/female pair within these groups were calculated using pedigree analysis. Values of COA for the genetically similar pairs (COA(avg) = 0.046) were significantly higher than the COA for the diverse pairs (COA(avg) = 0.013), suggesting that choosing male/female pairs on the basis of AFLP-based genetic distance may predict heterotic potential in crosses when GD >0.36. Keywords: Heterosis, Humulus lupulus, Inbreeding depression

Cruces Heteróticas Potenciales en Lúpulo Según Eestimados por Diversidad Genética Base-AFLP y Coeficiente de Coascendencia

El lúpulo es un “perennial dioecious” con plantas femeninas cultivadas comercialmente en propósitos de elaboración de cerveza. La selección de padres en el cruce de lúpulo en base de potencial heterótico no se ha reportado en literatura aunque la dominación se ha reportado en lúpulos por varios rasgos económicamente importantes. Los objetivos de este estudio eran determinar si la distancia genética en base de polimorfismo de longitudes de fragmentos amplificados (AFLP) entre las accesiones masculinas y femeninas reflejan exactamente las relaciones pedigríes y información actual sobre cruces heteróticas potenciales en lúpulo. Diecinueve cultivos fueron analizados en distancia genética a 82 accesiones masculinas que representan la diversidad asumida de lúpulo EE.UU. Distancias genéticas (GD) entre pares masculinos/femeninos fueron estimadas usando AFLP (490 bandas polimórficas). Estimaciones de comparación de distancia masculina a femenina se extendieron a partir de 0.169 a 0.62 con un promedio total de 0.306. Para cada lúpulo femenino, se identificaron y agruparon los 10 masculinos más genéticamente diversos y los 10 más genéticamente similares. Coeficientes de coascendencia (COA) para cada par masculino/femenino dentro de estos grupos fueron calculados usando análisis de pedigrí. Los valores COA de los pares genético similares (COA(avg) = 0.046) eran perceptiblemente más altos que el COA de los pares diversos (COA(avg) = 0.013), sugiriendo que elegir pares masculinos/femeninos en base de distancia genética AFLP pueden predecir potencial heterótico en cruces cuando GD >0.36. Palabras claves: Heterosis, Humulus Lupulus, Depresión de endogamia