Potential Heterotic Groups in Hop as Determined by AFLP Analysis

Abstract

␤-acid was negatively correlated among 112 female (r ϭ Ϫ0.78), and among 74 male hop genotypes (r ϭ Ϫ0.85). Hop (Humulus lupulus L.) is a perennial, dioecious species inAdditive genetic variation was detected for yield, ␣and which the female inflorescence (cones) are harvested and used in the beer-brewing process to impart bittering and/or flavoring to beer.␤-acid content, cohumulone, and hop storage index for Hop breeders have typically utilized clonal selection and hybridization both males and females in a North Carolin Design I to develop new cultivars. The use of genetically diverse parents for analysis of 25 yr of USDA historical data (Henning et al., the purpose of capturing heterosis in the offspring has received little 1997a). They also reported negative genetic correlations attention from hop breeders. The objective of this research was to between ␣-acid and ␤-acid content, and between ␤-acid assign male (N ϭ 80) and female (N ϭ 26) hop genotypes into potential and hop storage index, and positive genetic correlations heterotic groups using AFLP-generated molecular markers. The six between cohumulone and yield, and cohumulone and AFLP primers used in this study amplified 550 total fragments, of which 490 (89.1%) were polymorphic. A genetic distance (GD) matrix hop storage index. Genetic variation in hop has also was computed from the binary data matrix, and groupings and sumbeen reported for essential oil concentration (Henning mary statistics were calculated from the GD matrix. Two major cluset al., 1997b) and mineral concentration (Keller and ters were observed, one composed primarily of European hops, while Likens, 1955). the second group was composed primarily of European-wild Ameri-Several molecular marker tools have been employed can hybrids. The two major clusters were further subdivided into 13 to assess genetic diversity in hop, including amplified smaller clusters (two female, nine male, two male and female) based fragment length polymorphsim (AFLP) (Hartl and Seeon a qualitative analysis. These results suggest potential parental combinations for hop researchers and breeders to study heterosis in hop.

AFLP Discrimination of Native North American and Cultivated Hop

“…These genotypes are characterized by having a higher bittering acid potential and some level of powdery mildew (Podosphaera macularis Braun and Takamatus) resistance. In general, the subgroupings of A2 were similar to earlier hop characterization work based on genetic markers ( Jakse et al, 2001;Pillay and Kenny, 1996;Seefelder et al, 2000;Townsend and Henning, 2005).…”

“…Several research groups have demonstrated the ability of various molecular marker systems to measure genetic distance among hop genotypes. Generally, genetic marker‐based assessment suggests modern hop cultivars derive from European or European × native American germplasm pools (Jakse et al, 2001; Patzak, 2002; Pillay and Kenny, 1996; Seefelder et al, 2000; Townsend and Henning, 2005). In a microsatellite analysis of 124 hop accessions from Europe, Asia, and North America, Jakse et al (2004) found that European cultivated and native hop accessions contained limited allelic variation compared to North American cultivars and native accessions.…”

Phenotypic and molecular selection of yellow passion fruit progenies in the second cycle of recurrent selection

“…Thus, based on the known level of genetic variability of a population and the greatest genetic distance between the plants, the genetic gains can be quantified. For some crops these procedures have been successfully adopted, optimizing the diversity in the selected parents (Townsend and Henning 2005).…”

Registration of High‐Breeding‐Value Male Hop Germplasm USDA 21089M

“…This accession reportedly had resistance to aphids (Wagner, 1974) and for this purpose it was integrated into the USDA germplasm collection. USDA 21089M is thought to be a wild landrace from the Balkans in south‐central Europe as shown by genetic diversity studies conducted with molecular markers (Townsend and Henning, 2005). As such, little genetic similarity exists with other European landraces, such as Hallertauer, Tettnanger, or Saazer.…”