Growth regulators and their reflection on different hop genotypes cultivated under in vitro conditions

R De-Souza,J L M Coimbra,C R Adams,A F Guidolin,A Michel,R C De-Melo

doi:10.1590/1519-6984.242596

Abstract

Abstract Hops is a new culture in Brazil. Tissue culture can be an important technique for rapid hop propagation. This paper aims to characterize responses from different genotypes under different growth regulators through the interrelationship of response variables important to hop in vitro growth. Three genotypes were cultivated in six culture media with different combinations of growth regulators, BAP (6-benzylaminopurine), IAA (3-indolacetic acid) and GA3 (gibberellic acid). The means were compared by orthogonal contrasts and the interrelationship of the response variables was performed by path analysis. American genotypes showed favorable root development under the BAP + IAA combination, while the use of IAA improved shoot development. The origin of genotypes was important for defining the best protocol for in vitro cultivation. The path coefficient showed that the variable number of shoots has stronger direct effect on the number of nodal segments. Additionally, in tissue culture assays, the use of a covariable and proper error distribution significantly increased experimental accuracy.

Highlights

Hops (Humulus lupulus L.) is a perennial, dioecious, climbing-growing plant from the Cannabaceae family
Aware of the many possibilities and difficulties for selecting culture media for in vitro hop cultivation, we propose to characterize the responses from different genotypes under different growth regulators through the interrelationship of response variables important to in vitro hop growth (Humulus lupulus L.)
An enormous number of “zeros” are often counted in assessments of experiments, because the organ of interest is not formed, which can be explained by the inhibitory effect of the growth regulator or its absence

Summary

Introduction

Hops (Humulus lupulus L.) is a perennial, dioecious, climbing-growing plant from the Cannabaceae family. Female plants produce the cone, a structure that gives rise to a substance called lupulin. It is mainly used in the production of beer, due to its organoleptic and antibacterial properties that increase beer foam stability. It is used in the manufacture of drugs, mainly as a natural tranquilizer. Brazil is ranked as the third largest beer producer in the world. All the hops used in the production of Brazilian beer are imported. The total volume is about 3,500 tons per year, with an annual cost close to US $ 60 million (Brasil, 2019a)

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