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ARS Home » Plains Area » Fort Collins, Colorado » Center for Agricultural Resources Research » Agricultural Genetic Resources Preservation Research » Research » Publications at this Location » Publication #428680
Research Project: Curation and Research to Safeguard and Expand Collections of Plant and Microbial Genetic Resources and Associated Descriptive Information

Location: Agricultural Genetic Resources Preservation Research

Title: Thidiazuron and trans-zeatin riboside promote development of shoots and nodes in in vitro propagation of hops (Humulus lupulus L. var. lupulus)

Author
item Staats, Elise
item Jenderek, Maria

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/10/2025
Publication Date: 1/13/2026
Citation: Staats, E.R., Jenderek, M.M. 2026. Thidiazuron and trans-zeatin riboside promote development of shoots and nodes in in vitro propagation of hops (Humulus lupulus L. var. lupulus). Frontiers in Plant Science. 16. https://doi.org/10.3389/fpls.2025.1694038.
DOI: https://doi.org/10.3389/fpls.2025.1694038

Interpretive Summary: Hop is considered as a horticultural and an industrial crop. It is used in beer production and in herbal medicine. In 2024 its market value was $9.4 billion. To accelerate development of planting material a robust method for tissue culture propagation is needed. This experiment unfolded a plant growth regulator treatments that lead to a significant increase of plants of the crop.

Technical Abstract: Hop (Humulus lupulus L. var. lupulus) is a dioecious, climbing plant considered as a horticultural and an industrial crop. It is propagated vegetatively by root cuttings and to a lesser extent by tissue cultures. Various plant growth regulators were applied in hop tissue culture propagation such as benzyladenine, kinetin, indole-3-acetic acid, thidazuron, zeatin, gibberellic acid and glucose. We have aimed in vitro propagation of three randomly selected genotypes (PI 546055, PI 558687 and PI 617389) from the USDA ARS hop germplasm collection to work out a procedure for developing large quantity of shoots, nodes and long main shoots using 15 plant growth regulator treatments, in three propagation cycles lasting 4 wks each. The most shoots and nodes were developed in treatments with thidiazuron (15.9+1.34 shoots; 40.6+3.6 nodes); however, literature reports a successful use of this plant growth regulator in selected hop cultivars, thidiazuron caused hyperhydricity in PI 546055, that seems to be genotype dependent; hence its use in hop micropropagation should be discreet. No physiological disorders were observed in the other treatments. However lower, the shoot (8.4+1.34) and node number (24.9+3.6) were not far from a treatment with 3.0 mg L-1 trans zeatin riboside, the length of the main shoots (9.3+0.92 cm) was not significantly different from the other treatments except for compounded treatment of 0.01 benzyladenine+0.025 gibberellic acid and in all thidiazuron treatments. The 3.0 mg L-1 of trans zeatin riboside was the top treatment for micropropagation of the three hop accessions; this treatment will be used for a variety of accessions from the USDA hop germplasm collection; it may be also useful when large quantities of plantlets are needed.