Hop Cultivars Research Articles

Susceptibility of Hop Cultivars and Rootstock to Downy Mildew Caused by Pseudoperonospora humuli

Annual downy mildew [Pseudoperonospora humuli (Miyabe & Takah.) G.W. Wilson, (1914)] epidemics threaten hop (Humulus lupulus L. var. lupulus) production throughout the eastern United States. Rootstock rot complicates foliar disease assessments because dormant buds may rot before producing a symptomatic basal shoot and noncolonized buds produce healthy shoots. We selected 12 cultivars to evaluate downy mildew susceptibility (2016 and 2017) and examined the rhizomes of a subset of six cultivars (2018) that showed clear differences in foliar disease ratings to determine rootstock rot susceptibility. Trials were conducted on nontrellised hop yards established at two research farms in 2016 and managed without fungicides. The relative area under the disease progress curve (rAUDPC) values for foliar disease severity and density ratings were consistently higher for ‘Cascade’, ‘Centennial’, and ‘Nugget’ than for ‘Newport’, ‘Tahoma’, and ‘Columbia’. Only ‘Centennial’ had a higher wet-rot cortex discoloration (CD) incidence (71.5%) and severity (31.9%) in its rhizomes than the other cultivars. Among cultivars with low foliar disease levels, Columbia was less vigorous (shoots/plant) than ‘Tahoma’, but had similar wet-rot CD (incidence, 46.4% to 47.2%; severity, 12.5% to 17.7%). The levels of wet-rot CD for ‘Tahoma’, ‘Newport’, and ‘Columbia’ were comparable to those of some cultivars with more severe foliar disease symptoms (‘Nugget’ and ‘Cascade’). Differences in foliar disease among cultivars with similar levels of rootstock rot suggest a resistance defense mechanism to P. humuli. Additional work is needed to clarify rootstock infection sites and characterize defense responses to aid future breeding efforts.

Characterization of Wild Corsican Hops and Assessment of the Performances of German Hops in Corsican Environmental Conditions through a Multidisciplinary Approach

Hops (Humulus lupulus L.) is a species that grows spontaneously in Corsica, but the characterization of this species in this territory has not yet been investigated. The main objectives of this study are to explore the features of wild hops from Corsica and to determine the effect of the island terroir on some cultivars in the first year of growth. A multidisciplinary approach consisting of the genetic analysis, morphological comparison and chemical characterization of essential oils was carried out on four wild Corsican hops and three hop cultivars grown in Tettnang, Germany and Corsica, France. The morphological and GC-MS analysis of Corsican wild hops, set cluster coastal samples apart from the one far from the coast. This dissimilarity is supported by the SSR analysis by two of the three coastal accessions. The genetics demonstrate a proximity between the European noble cultivar Tettnanger and the mountain Corsican wild hop from Corte. The morphological comparison between German hops cultivated in Tettnang and in Corsican soil, and the GC-MS characterization of their essential oils’ chemical profiles, show different features between year 0 and year +1 for each sample. This multidisciplinary approach highlights an acclimatization of hop cultivars to the Corsican terroir one year after planting.

Core RNA Interference Genes Involved in miRNA and Ta-siRNA Biogenesis in Hops and Their Expression Analysis after Challenging with Verticillium nonalfalfae.

RNA interference is an evolutionary conserved mechanism by which organisms regulate the expression of genes in a sequence-specific manner to modulate defense responses against various abiotic or biotic stresses. Hops are grown for their use in brewing and, in recent years, for the pharmaceutical industry. Hop production is threatened by many phytopathogens, of which Verticillium, the causal agent of Verticillium wilt, is a major contributor to yield losses. In the present study, we performed identification, characterization, phylogenetic, and expression analyses of three Argonaute, two Dicer-like, and two RNA-dependent RNA polymerase genes in the susceptible hop cultivar Celeia and the resistant cultivar Wye Target after infection with Verticillium nonalfalfae. Phylogeny results showed clustering of hop RNAi proteins with their orthologues from the closely related species Cannabis sativa, Morus notabilis and Ziziphus jujuba which form a common cluster with species of the Rosaceae family. Expression analysis revealed downregulation of argonaute 2 in both cultivars on the third day post-inoculation, which may result in reduced AGO2-siRNA-mediated posttranscriptional gene silencing. Both cultivars may also repress ta-siRNA biogenesis at different dpi, as we observed downregulation of argonaute 7 in the susceptible cultivar on day 1 and downregulation of RDR6 in the resistant cultivar on day 3 after inoculation.

Hop stunt viroid detection in hops (Humulus lupulus) in Australia

Hop stunt viroid (HSVd), a significant pathogen of some hop cultivars, was detected for the first time in hops in Australia. Plants were tested for graft-transmissible pathogens prior to their use in research trials. Upon observing symptoms indicative of potential viroid infection, RNA was extracted and amplified using reverse transcription polymerase chain reaction (RT-PCR); HSVd identity was confirmed by sequencing.

Differences in New Zealand Hop Cultivars Based on Their Unique Volatile Compounds: An Integrated Fingerprinting and Chemometrics Approach.

Hop aroma characteristics originate from hop essential oils, which have complex chemical profiles that remain poorly understood, particularly for New Zealand hops. The aim of this study was to determine volatile compounds that distinguish New Zealand hop cultivars. Untargeted fingerprinting methods based on headspace gas chromatography mass spectrometry (GC-MS) were used to analyse nine hop cultivars. A total of 61 volatile compounds were identified as compounds that differentiated the commercial hop varieties using advanced chemometrics and feature selection techniques. Similarities in volatile composition were found between Wakatu, Wai-iti™ and Kohatu®, which are rich in alcohols. Another grouping was found between Waimea™ and Nelson Sauvin™, where ketones and esters were commonly found. Rakau™ was distinct from the other eight cultivars, distinguished by 2-methylbutyl 3-methylbutanoate and methanethiol hexanoate. Riwaka™ contained the greatest number of discriminating volatile compounds when compared to other cultivars, which was dominated by terpenoids, such as geranyl 2-methylbutanoate, perillene and D-limonene. The chemical fingerprinting approach successfully identified volatile compounds that had not been previously found in New Zealand hop cultivars and that discriminated the commercial cultivars. The data obtained in the present study further extend the knowledge of New Zealand hops and will help facilitate targeted breeding.

A new perspective of a well-recognized raw material: Phenolic content, antioxidant and antimicrobial activities and α- and β-acids profile of Brazilian hop (Humulus lupulus L.) extracts

Hop is a plant with several biological properties. Many factors affect both the presence and concentration of hop compounds, such as cultivar, location and growth conditions. Recently, the interest of hop cultivation in Brazil has grown despite the tropical weather and it has been possible to obtain hop completely cultivated in Brazilian soil. This study analyzed the chemical composition and verified the antioxidant and antimicrobial activities of Brazilian hop hydroethanolic extracts in comparison to a commercially available hop cultivar. Brazilian hops were a good source of flavonoids (5.72–12.82 mg CE/g dw), and presented a high content of phenolic compounds, in particular the Canastra cultivar (35.1 mg GAE/g dw). The Brazilian cultivars showed interesting antioxidant and antimicrobial proprieties. Gram-positive and Gram-negative bacteria were susceptible to hop hydroethanolic extracts and Staphylococcus aureus was inhibited by the extracts of all cultivars. The extracts presented antifungal activity against Byssochlamys nivea and significant growth inhibition at the higher concentration tested (20 μl/ml). The hydroethanolic extracts exhibited a high content of α- and β-acids, mainly the Vitoria, Columbus and Canastra cultivars, reaching almost 60% (w/w). These characteristics evidenced the potential application of Brazilian hops as raw materials in both pharmaceutical and food industries.

High genetic and chemical diversity of wild hop populations from Central Italy with signals of a genetic structure influenced by both sexual and asexual reproduction

In order to investigate the intraspecific diversity of wild Humulus lupulus (hop) in Central Italy, 12 populations were evaluated for their genetic polymorphism by means of 13 SSR loci together with six commercial cultivars as a reference. High levels of polymorphism were found across the populations, being 140 the number of multilocus genotypes over 159 samples analyzed. Moreover, the observed heterozygosity was higher than expected in most of the populations. High levels of gene flow were thus envisaged to occur within and among wild populations, and our sampling strategy allowed us to gain insights on the propagation modes of this species, i.e. clonal versus sexual propagation. Nevertheless, a genetic structure of populations with at least five genetically different clusters was disclosed. Private alleles were observed in both wild and cultivated hops. Chemical analysis of bittering and aromatic quality of female flowers from a subset of 8 wild populations revealed a high variability among plants, especially for essential oil components. Overall, the high variability of wild accessions here examined represent a valid source to be exploited in future breeding programs for new or improved hop cultivars development.

Evaluation of Czech hop cultivars since 2010 till 2019

Czech hop cultivars were evaluated from 2010 to 2019. A total of 13 cultivars were assessed. The highest yield per plant was found out in cv. Kazbek (3.66 kg/plant), whereas the lowest in cv. Saazer (2.02 kg/plant). Rubín and Boomerang are the cultivars with the lowest variability of the yield per plant. On the contrary, the highest variability was shown by cv. Kazbek. Conclusively the highest content of alpha acids was recorded in cv. Gaia (13.81%), whereas Saazer is the cultivar with the lowest content (2.87%). Significantly highest content of beta acids were recorded in cvs. Gaia, Vital, Boomerang and Bohemie. On the contrary, the lowest content of beta acids was found in cvs. Saazer, Rubín and Bor (below 4%). Kazbek is the cultivar with the highest ratio of cohumulone (36.67% rel.). Cvs. Premiant and Harmonie show the lowest ratio of cohumulone (19.63% rel.). The lowest ratio of myrcene (18.91% rel.) and caryophyllene (8.26% rel.) was recorded in cv. Saazer. The highest ratio of farnesene was found in cv. Saazer (13.34% rel.) and cv. Saaz Late (10.22% rel.). A wide range was found in the ratio of humulene: from 2.15% rel. (cv. Vital) to 35.76% rel. (cv. Bor). Cv. Gaia has the highest ratio of selinene (19.77% rel.).

Novel and efficient approach to identify hop cultivars (Humulus lupulus L.) using cultivar identification diagram strategy based on fingerprint of flavonol di- and tri-O-glycosides

The profile of flavonoids in hops (Humulus lupulus L.) showed a significant cultivar diversity applicable for distinguishing cultivars. The aims of this study were (1) to identify and describe flavonol di- and tri-glycosides in hops; (2) to analyze the profile of flavonol glycosides in various hop cultivars; and (3) to develop a new approach for identifying hop cultivars using a manual cultivar identification diagram that consisted of the ratios between specific flavonol di- and tri-glycosides. The total of 22 different flavonol O-glucosides were detected and tentatively identified using liquid chromatography (RP-HPLC) coupled with high-resolution mass spectrometry (HR-MS/MS). The identified O-flavonol glycosides, mainly containing aglycones, quercetin, kaempferol and myricetin, were categorized into five groups according to their sugar moieties. Furthermore, fourteen characteristic peaks with a low sample-to-sample variation and acceptable coefficient of variation (< 20%) throughout growing seasons were selected for chemometric analysis. Hierarchical cluster analysis (HCA) was applied to two data sets to characterize the similarity and differences among samples: one data set contained five hop cultivars common in the Czech Republic and the second one consisted of 17 hop cultivars from around the world. The results of the HCA of flavonol di- and tri-glycosides proved the genotypic effect on their profile and allowed to select compounds primarily responsible for clustering hop cultivars into groups. These compounds were used for developing an efficient cultivar identification strategy based on the manual cultivar identification diagram. The functionality of the identification diagram was successfully tested and allowed, based on the specific ratios between flavonol glucosides, reliable discrimination among the five most common hop cultivars planted in the Czech Republic. Compared to the genetic or chemotaxonomic methods, the newly developed approach for the hop cultivar identification provided reliable results even if the tested materials were hop pellets or beer.

Beyond Beer: Hop Shoot Production and Nutritional Composition under Mediterranean Climatic Conditions

For hop growers, surplus shoots are generally a useless by-product of cultivation. Conversely, they may represent a valuable resource due to rising interest towards healthy and traditional foods. A field trial was carried out in Central Italy to characterize shoot production (number of emerged shoots, shoot fresh weight, marketable shoot yield, and shoot diameter) of three commercial hop cultivars (Cascade, Challenger, and Hallertauer Magnum) and to survey shoot proximate composition (ash, ether extract, crude protein, and crude fiber). Green shoots were harvested when they were from 20 to 40 cm in length. The results from two years showed that there was significant difference among the varieties and between growing seasons, both for yield traits and for nutritional composition. H. Magnum showed the highest marketable shoot yield (152 g per plant, two-year mean), while Cascade had the best proximate composition. The number of emerged shoots per plant varied from 62.5 of Cascade to 84.3 of H. Magnum over a two-year average. Marketable shoot yield showed a positive relationship with number of shoots and average shoot fresh weight, while no significant correlation was found with shoot diameter. Hop shoots proved to be a low-fat food (ether extract from 2 to 6% dry matter (DM)) with high protein (from 22 to 30% DM) and fiber content (from 10 to 16% DM).

The Effector Repertoire of the Hop Downy Mildew Pathogen Pseudoperonospora humuli.

Pseudoperonospora humuli is an obligate biotrophic oomycete that causes downy mildew (DM), one of the most destructive diseases of cultivated hop that can lead to 100% crop loss in susceptible cultivars. We used the published genome of P. humuli to predict the secretome and effectorome and analyze the transcriptome variation among diverse isolates and during infection of hop leaves. Mining the predicted coding genes of the sequenced isolate OR502AA of P. humuli revealed a secretome of 1,250 genes. We identified 296 RXLR and RXLR-like effector-encoding genes in the secretome. Among the predicted RXLRs, there were several WY-motif-containing effectors that lacked canonical RXLR domains. Transcriptome analysis of sporangia from 12 different isolates collected from various hop cultivars revealed 754 secreted proteins and 201 RXLR effectors that showed transcript evidence across all isolates with reads per kilobase million (RPKM) values > 0. RNA-seq analysis of OR502AA-infected hop leaf samples at different time points after infection revealed highly expressed effectors that may play a relevant role in pathogenicity. Quantitative RT-PCR analysis confirmed the differential expression of selected effectors. We identified a set of P. humuli core effectors that showed transcript evidence in all tested isolates and elevated expression during infection. These effectors are ideal candidates for functional analysis and effector-assisted breeding to develop DM resistant hop cultivars.

Distribution of root system of hop plants in hop gardens with regular rows cultivation

Spatial distribution of the root system of hop (Humulus lupulus L.) in the soil profile is a less explored issue. However, it is known that it can play an important role in the development of new tillage technologies, fertilisation and irrigation, including the use of precision farming principles. In the period from 2015 to 2018, the distribution of the hop root system was evaluated on twelve hop plants of five Czech hop cultivars. The age of the plants ranged from 3 to 15 years. The evaluation took place in the Saaz region at regularly cultivated hop gardens. As part of the evaluation, the root systems of hop plants were removed from the soil profile and subsequently spatially reconstructed. With the help of infrared image analysis, the root intensity in the soil profile and the morphology of the root systems were determined. The root depth of the plants ranged from 1 m to 2.25 m. The lateral width of the hop root system ranged from 0.6 m to 1.5 m. As a result of the rows cultivation, the lateral development of the roots in the upper soil layers was limited. The results were confirmed using the infrared image analysis method to specify the distribution of the root system and the root density of hop plants in the soil profile.

The Identification of a New Species, Diaporthe humulicola, a Pathogen Causing Diaporthe Leaf Spot on Common Hop.

Common hop, Humulus lupulus, is a commercially important crop in the United States, with an increasing number of hop yards being established in the Northeast. In 2018, a new fungal disease was observed at two research hop yards in Connecticut. This new pathogen affected all hop cultivars being grown and caused leaf spots and browning of cones. The causal organism was isolated and Koch's postulates were performed to confirm pathogenicity. The disease symptoms were similar to the previously described Phoma wilt; however, morphological and phylogenetic analyses placed the causal organism as a new species of Diaporthe. We propose the name Diaporthe humulicola. The disease increased under hot, humid conditions (around 24°C and 90% relative humidity), which prevail during the summer in the northeastern United States as well as other parts of the country. An in vitro preliminary assessment of fungicide sensitivity revealed that pyraclostrobin and boscalid inhibited D. humulicola growth in culture and should be further assessed for field efficacy against this new disease of hop. The proper identification and monitoring of this pathogen will be important to inform hop growers of this new threat.

Changes in the Phenolic Compounds of Hop (Humulus lupulus L.) Induced by Infection with Verticillium nonalfalfae, the Causal Agent of Hop Verticillium Wilt.

Phenolic compounds are involved in plant responses to various biotic and abiotic stress factors, with many studies suggesting their role in defense mechanisms against fungal pathogens. Soilborne vascular pathogen Verticillium nonalfalfae causes severe wilting and consequent dieback in a wide range of economically important crops, including hops (Humulus lupulus L.). In this study, we investigated the differential accumulation of phenolics in the susceptible “Celeia” and resistant “Wye Target” hop cultivars during the pathogenesis of Verticillium wilt. Quantitative polymerase chain reaction showed that colonization in the roots of both cultivars was intensive, but decreased continuously throughout the experiment in the resistant cultivar, while the relative fungal amount continuously increased in the stems of the susceptible cultivar. In response to colonization in the roots of the resistant cultivar, a significant increase in total flavanols was detected at three days postinoculation (dpi), suggesting a possible role in preventing fungus spread into the stems. The accumulation of phenolic compounds was less pronounced in the stems of the resistant cultivar since, compared to the latter, significant increases in flavonols at 3 and 15 dpi and hydroxycinnamic acids at 6 dpi were observed in the stems of the susceptible cultivar.

Identification of tandem repeat families from long-read sequences of Humulus lupulus.

Hop (Humulus lupulus L.) is known for its use as a bittering agent in beer and has a rich history of cultivation, beginning in Europe and now spanning the globe. There are five wild varieties worldwide, which may have been introgressed with cultivated varieties. As a dioecious species, its obligate outcrossing, non-Mendelian inheritance, and genomic structural variability have confounded directed breeding efforts. Consequently, understanding the hop genome represents a considerable challenge, requiring additional resources. In order to facilitate investigations into the transmission genetics of hop, we report here a tandem repeat discovery pipeline developed using k-mer filtering and dot plot analysis of PacBio long-read sequences from the hop cultivar Apollo. From this we identified 17 new and distinct tandem repeat sequence families, which represent candidates for FISH probe development. For two of these candidates, HuluTR120 and HuluTR225, we produced oligonucleotide FISH probes from conserved regions of and demonstrated their utility by staining meiotic chromosomes from wild hop, var. neomexicanus to address, for example, questions about hop transmission genetics. Collectively, these tandem repeat sequence families represent new resources suitable for development of additional cytogenomic tools for hop research.

Mapping the Gene Expression Spectrum of Mediator Subunits in Response to Viroid Infection in Plants.

The mediator (MED) represents a large, conserved, multi-subunit protein complex that regulates gene expression through interactions with RNA polymerase II and enhancer-bound transcription factors. Expanding research accomplishments suggest the predominant role of plant MED subunits in the regulation of various physiological and developmental processes, including the biotic stress response against bacterial and fungal pathogens. However, the involvement of MED subunits in virus/viroid pathogenesis remains elusive. In this study, we investigated for the first time the gene expression modulation of selected MED subunits in response to five viroid species (Apple fruit crinkle viroid (AFCVd), Citrus bark cracking viroid (CBCVd), Hop latent viroid (HLVd), Hop stunt viroid (HSVd), and Potato spindle tuber viroid (PSTVd)) in two model plant species (Nicotiana tabacum and N. benthamiana) and a commercially important hop (Humulus lupulus) cultivar. Our results showed a differential expression pattern of MED subunits in response to a viroid infection. The individual plant MED subunits displayed a differential and tailored expression pattern in response to different viroid species, suggesting that the MED expression is viroid- and plant species-dependent. The explicit evidence obtained from our results warrants further investigation into the association of the MED subunit with symptom development. Together, we provide a comprehensive portrait of MED subunit expression in response to viroid infection and a plausible involvement of MED subunits in fine-tuning transcriptional reprogramming in response to viroid infection, suggesting them as a potential candidate for rewiring the defense response network in plants against pathogens.

Photosynthetic Activity of Six Hop (Humulus lupulus L.) Cultivars under Different Temperature Treatments

The Pacific Northwest grows the majority of hops in the United States; however, the region is experiencing an increase in the number of days with high heat. In addition, there is an increased interest in growing hops in other warmer regions of the United States. To understand how hop plants respond to high temperatures, we measured several physiological traits of six hop cultivars under a range of temperatures from 15 to 45 °C. We found that hop plants achieved maximal carbon assimilation at temperatures of 21 to 39 °C when given sufficient water. At temperatures of 41 °C and higher, all cultivars experienced declines in carbon assimilation. This was likely due to multiple effects on the cell, including damage to photosystem II (PSII), as reflected in declines in FV/FM, damage to membrane integrity as reflected in electrolyte leakage at high temperatures, and declines in Rubisco activity likely due to degradation of Rubisco activase, as reflected in declines in Vc,max. ‘Cascade’, ‘Willamette’, and ‘Southern Brewer’ may be good candidates for growing in warm climates because all experience relatively high rates of carbon assimilation at high temperatures and did not experience significant declines in FV/FM or increases in electrolyte leakage. ‘Chinook’ appeared susceptible to extreme heat stress and exhibited evidence of irreparable damage to PSII and membrane integrity at 45 °C.

Hop (Humulus lupulus L.) terroir has large effect on a glycosylated green leaf volatile but not on other aroma glycosides

Genetics and environment both influence the content of hop (Humulus lupulus L.) aroma compounds. The effects of these two factors on aroma glycosides, which can change the aroma profile of beer over time, were examined in a preliminary study. Twenty-three hop cultivars were grown in the northwestern United States in two locations with distinct terroirs. UPLC–MS/MS analysis of hop cone extracts revealed that growing location had a large effect on hexyl glucoside levels but only a negligible effect on levels of linalyl, raspberry ketone, and 2-phenylethyl glucoside, which were mostly affected by genetic differences. The large terroir effect on hexyl glucoside, which releases a green leaf volatile with a grassy aroma when hydrolyzed, but not on the other aroma glucosides, which have more desirable aromas when hydrolyzed, could have an impact on beer aroma profiles.

Influence of weather conditions, irrigation and plant age on yield and alpha-acids content of Czech hop (Humulus lupulus L.) cultivars

This study quantifies the effects of weather conditions, irrigation, and plant age on yield and alpha-acids content of Czech hop cultivars Saaz, Sládek, Premiant and Agnus in a 25-year long period, i.e., from 1993 to 2018. The yields of Czech hop cultivars were increasing for the first three years of plant age until they stabilized and then started to decline slightly for 15 to 20 years until they reached the optimal time for replanting. The highest alpha-acids content in hop cones was achieved in the first year of cultivation, followed by a logarithmic decline in the upcoming years. Rainfall was the most significant factor that positively influenced the yield of Saaz hops with correlations of r = 0.59 and 0.61 (P &amp;lt; 0.01) for total seasonal rainfall (April–August), 0.65 (P &amp;lt; 0.001) and 0.60 (P &amp;lt; 0.01) for daily rainfall above 3 mm, 0.37 (P &amp;lt; 0.05) and 0.58 (P &amp;lt; 0.01) for rainfall in May and 0.50 (P &amp;lt; 0.01) and 0.32 (P &amp;lt; 0.05) in July in the Saaz region and the Stekník farm, respectively. The yield of cultivars Sládek, Premiant and Agnus was not statistically influenced by the amount of precipitation, but there was a positive effect of irrigation level on yield increase with correlations 0.58 (P &amp;lt; 0.01), 0.55 and 0.49 (P &amp;lt; 0.05), respectively. High air temperatures during summer were the most significant factor that negatively influenced the alpha-acids content with the correlations ranging from –0.56 to –0.83. However, cv. Agnus showed a stable weather-independent alpha-acids content.

Plant-parasitic nematodes associated with the root zone of hop cultivars planted in a Florida field soil.

In early 2016, hop plants were introduced into Florida. By late 2016, the hop plants were showing stunted growth and were heavily parasitized by Meloidogyne javanica. In this study, we determined host susceptibility of 14 hop cultivars to M. javanica in a greenhouse experiment and monitored population development of plant-parasitic nematode species in the root zone of 17 hop cultivars planted in three newly established hop yards in Florida. Plant-parasitic nematodes in the rooting zone soil of field grown hop plants included M. javanica, Pratylenchus brachyurus, Paratrichodorus minor, Belonolaimus longicaudatus, Xiphinema setariae/vulgare complex, Mesocriconema xenoplax, and Helicotylenchus dihystera; however, soil population densities of P. minor, B. longicaudatus, X. setariae/vulgare complex, M. xenoplax, and H. dihystera remained low through the study. Root galling, M. javanica egg production, and soil population densities of M. javanica were consistently large on the ‘Canadian Red Vine’, ‘Centennial’, ‘Chinook’, and ‘Comet’ cultivars, and small on the ‘Galena’ and ‘Triple Perle’ cultivars. No differences were observed in soil population densities of P. brachyurus among hop cultivars. Overall, our study provides the first report of plant-parasitic nematode population development in the root zone on hop cultivars planted in Florida.