GENETIC PARAMETER ESTIMATES FOR 5 TRAITS IN MALE HOP ACCESSIONS - A PRELIMINARY-STUDY

Much information on hop (Humulus lupulus) production and maintenance e xists but little is known about the genetics of specific traits. The o bjective of this study was to determine general combining ability (GCA ) and genetic correlations (r(g)) for five traits in six male hop acce ssions crossed to 14 different female accessions. Data for the study w ere extracted from USDA hop breeding records covering the past 25 year s. The analysis was performed with females nested within males across four replicates (years). We observed significant (P less than or equal to 0.05) GCA for all traits, with male 21361M exhibiting the highest GCA for yield (paternal half-sib avg. = 1,934 kg/ha); 21268M exhibitin g the highest GCA for alpha-acid levels (paternal half-sib avg. = 7.20 %), 19046M exhibiting the highest GCA for beta-acid levels (paternal h alf-sib avg. = 6.54%), 64035M exhibiting the most desirable cohumulone (COH) levels relative to total alpha-acids (paternal half-sib avg. = 24.1%), and 64037M exhibiting the most desirable value for hop storage index (HSI) (paternal half-sib avg. = 0.246). Significant positive ge netic correlations were observed between COH and yield (0.492) and bet ween COH and HSI (0.763). Significant negative genetic correlations we re observed between alpha-acid and beta-acid levels (-0.743) and beta- acid levels and HSI (-0.788). The results of this study, while prelimi nary, provide valuable information for hop breeders on choice of males for specific traits and a selection protocol guide for multiple trait selection.