Factors Controlling Flowering in the Hop (Humulus lupulus L.)

Thomas, Geraint M. H.; Schwabe, W. W.

doi:10.1093/oxfordjournals.aob.a084324

Cited by 36 publications

(34 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The critical daylength is genotype-dependent, although plants of both sexes must initiate a minimum number of nodes before flowering can be induced (e.g. 30-32 for the variety ' Fuggle ' ; Thomas & Schwabe, 1969). The influence of daylength on floral induction in male hop plants is less clear.…”

Section: mentioning

confidence: 99%

Sexual development and sex chromosomes in hop

et al. 2000

View full text Add to dashboard Cite

The stages of floral development in staminate and pistillate plants of hop (Humulus lupulus) were defined using scanning electron microscopy and light microscopy. Vegetative meristems of male and female plants are morphologically indistinguishable. On transition to the reproductive phase, inflorescence apices reduce greatly in size and striking developmental sex differences become apparent. The first sex-specific differences occur extremely early in floral ontogeny. Both male and female plants initiate inflorescence meristems at each leaf node, each meristem being enclosed within a bract. Male secondary inflorescence meristems give rise to clusters of asynchronously developing flowers. Female inflorescence meristems produce flowers arranged in ' cones '. Each male floral meristem initiates a whorl of five sepal primordia, followed by an inner whorl of five stamen primordia. There is no sign of carpel development at any stage. In females, two carpel primordia are initiated, surrounded at their base by a vestigial perianth whorl. No stamen development is observed. Several monoecious lines carry bisexual flowers, either within cymose panicles or within the basal bracts of terminal female inflorescences. Bisexual flowers usually possess perianth, stamen and carpel whorls. The central whorls are often highly variable, and range from a pair of stigmas fused to a thin central filament to a well developed gynoecium. Chimaeric central whorls consisting of fused staminoid-carpelloid structures also occur. Sex differences in unisexual hop flowers are determined at an extremely early stage in ontogeny. The inappropriate set of sex organs is suppressed before it becomes visible or, more probably, it is not initiated at all. Genes directing the development of sex are likely to act at an extremely early stage, well in advance of floral organogenesis. The sex chromosomes of dioecious hop plants are described, as well as the chromosome constitutions of monoecious plants and those carrying bisexual flowers.

show abstract

Section: mentioning

confidence: 99%

Sexual development and sex chromosomes in hop

et al. 2000

View full text Add to dashboard Cite

show abstract

“…In most cultivated plant species, the inheritance of yield is complex; influenced by a multitude of integrated physiological and biochemical processes, each with their own genetic basis [36,37] and hop is no exception [38-40]. Yield may also be influenced by a number of environmental factors, including water supply [41-44], nutrient availability, day length [41,45], irradiance [43,44], temperature [43,44], agricultural practice [46] and infestation of pests and diseases [47-50]. The identification of QTL influencing yield and their utilisation for MAS would greatly assist breeding for increased hop yield, by eliminating confounding environmental influences as well as allowing assessments of yield potential at the seedling stage, several years before maximal cone yields, or in non-yielding male plants.…”

Section: Introductionmentioning

confidence: 99%

Quantitative trait loci in hop (Humulus lupulus L.) reveal complex genetic architecture underlying variation in sex, yield and cone chemistry

et al. 2013

View full text Add to dashboard Cite

BackgroundHop (Humulus lupulus L.) is cultivated for its cones, the secondary metabolites of which contribute bitterness, flavour and aroma to beer. Molecular breeding methods, such as marker assisted selection (MAS), have great potential for improving the efficiency of hop breeding. The success of MAS is reliant on the identification of reliable marker-trait associations. This study used quantitative trait loci (QTL) analysis to identify marker-trait associations for hop, focusing on traits related to expediting plant sex identification, increasing yield capacity and improving bittering, flavour and aroma chemistry.ResultsQTL analysis was performed on two new linkage maps incorporating transferable Diversity Arrays Technology (DArT) markers. Sixty-three QTL were identified, influencing 36 of the 50 traits examined. A putative sex-linked marker was validated in a different pedigree, confirming the potential of this marker as a screening tool in hop breeding programs. An ontogenetically stable QTL was identified for the yield trait dry cone weight; and a QTL was identified for essential oil content, which verified the genetic basis for variation in secondary metabolite accumulation in hop cones. A total of 60 QTL were identified for 33 secondary metabolite traits. Of these, 51 were pleiotropic/linked, affecting a substantial number of secondary metabolites; nine were specific to individual secondary metabolites.ConclusionsPleiotropy and linkage, found for the first time to influence multiple hop secondary metabolites, have important implications for molecular selection methods. The selection of particular secondary metabolite profiles using pleiotropic/linked QTL will be challenging because of the difficulty of selecting for specific traits without adversely changing others. QTL specific to individual secondary metabolites, however, offer unequalled value to selection programs. In addition to their potential for selection, the QTL identified in this study advance our understanding of the genetic control of traits of current economic and breeding significance in hop and demonstrate the complex genetic architecture underlying variation in these traits. The linkage information obtained in this study, based on transferable markers, can be used to facilitate the validation of QTL, crucial to the success of MAS.

show abstract

“…2015 to maximum of 13 h 58 min on 21 June 2014 and 2015. Although photoperiod was not evaluated as a treatment in this experiment, similar daylength was imposed as a treatment factor on inflorescence development by Thomas and Schwabe (1969). Authors reported successful flower induction at 14 h daylengths; however, inflorescence was maximized for tested cultivars (Fuggle, CC 31, and New York Hop) when 16 h daylengths were imposed.…”

Section: Resultsmentioning

confidence: 98%

“…Optimal photoperiod within this geographical range has been cited (Davis and King, 2012) as one of the most significant factors contributing to hop production success. Thomas and Schwabe (1969) examined the influence of photoperiod on hop growth and development within a controlled greenhouse environment and found inflorescence development was maximized at 16 h daylength; however, response was dependent on cultivar. Results support the optimal reported geographic range for hop cultivation between 35°and 55°latitude based on daylength; however, additional investigations are necessary to ascertain relationships between photoperiod and inflorescence development.…”

mentioning

confidence: 99%

Growth, Strobile Yield, and Quality of Four Humulus lupulus Varieties Cultivated in a Protected Open-sided Greenhouse Structure

Pearson¹,

Smith²,

Chen³

2016

horts

View full text Add to dashboard Cite

Hops (Humulus lupulus) is a perennial, herbaceous crop cultivated for its strobiles, or cones, which contain a resinous compound used for flavoring and aroma in food, tea, and beer. The United States is the second largest global producer of hops with greater than 15,000 ha in production. Increased demand for hop products has recently resulted in production of hops in nontraditional production areas (non-Pacific northwest U.S. region). To examine cultivation potential of hops within the southeastern United States, 60 hop rhizomes consisting of four varieties were transplanted into native, deep sand soil (Candler and Tavares-Millhopper soil series) within a protected, open-sided greenhouse and evaluated for growth, strobile yield, and brewing values for a period of 2 years. Plant bine length was recorded weekly for 20 weeks throughout year 1 with mean bine lengths of 609, 498, 229, and 221 cm at harvest for ‘Chinook’, ‘Columbus’, ‘Amalia’ and ‘Neo1’, respectively. Mean harvested strobile dry weight recorded for year 1 was 21.2, 17.9, 9.0, and 8.2 g/plant for ‘Columbus’, ‘Chinook’, ‘Neo1’ and ‘Amalia’, respectively. With the exception of ‘Neo1’, mean strobile mass was lower for all cultivars during year 2 with 16.6, 10.3, 25.8, and 2.6 g/plant for ‘Columbus’, ‘Chinook’, ‘Neo1’ and ‘Amalia’, respectively. Alpha acid concentrations by percentage strobile mass for year 1 were 6.8%, 9.7%, 3.8%, and 4.3% for ‘Columbus’, ‘Chinook’, ‘Amalia’, and ‘Neo1’, respectively. Alpha acids varied year 2 with concentrations of 4.8%, 10.4%, and 5.6% for ‘Columbus’, ‘Chinook’, and ‘Neo1’, respectively. Findings support viability of hop production in the southeastern United States and establish the benchmark for future varietal trialing investigations.

show abstract

Factors Controlling Flowering in the Hop (Humulus lupulus L.)

Cited by 36 publications

References 0 publications

Sexual development and sex chromosomes in hop

Sexual development and sex chromosomes in hop

Quantitative trait loci in hop (Humulus lupulus L.) reveal complex genetic architecture underlying variation in sex, yield and cone chemistry

Growth, Strobile Yield, and Quality of Four Humulus lupulus Varieties Cultivated in a Protected Open-sided Greenhouse Structure

Contact Info

Product

Resources

About