Influence of ethephon on growth and flowering of flue-cured tobacco

Tobacco (<i>Nicotiana tabacum</i> L.) leaf initiation stops when floral induction is completed. Floral induction (an internal biochemical change which signals development of flowers) can occur prematurely, during the pre- and/or post-transplant environment. Plants which flower prematurely have few leaves and low yields. Removal of the influorescence on these plants will break apical dominance and allow production of additional leaves from axillary bud. This practice requires additional labor and increases production costs. Objectives of this study were to 1) determine how application timing, rate, localization, and on-plant duration of ethephon (2-chloroethylphosphonic acid) influences growth and flowering of flue-cured ‘NC 82’ tobacco; 2) examine the relationship between temperatures in the seedling environment and premature flowering and determine how time of plant bed cover removal affects premature flowering; and 3) quantify the ethylene released from buds, leaves, stems, and roots of tobacco seedlings at various days after application of ethephon. Ethephon applied to flue-cured tobacco seedlings before the completion of floral induction significantly reduced premature flowering and increased days to flower, number of leaf nodes per plant, and yield. Multiple applications and increased rates of ethephon did not increase the number of leaf nodes beyond the level obtained from a single application of 960 mg L⁻¹ ethephon solution applied at the rate of 44 mL m⁻² of plant bed. In wash-off studies, maximum benefit was obtained when ethephon remained on the seedlings one to two hours after application. In localization studies, increases in number of leaf nodes per plant were not different when 0.09 and 0.51 mg of ethephon was applied to the bud and largest leaf, respectively. Ethylene released from ethephon-treated greenhouse seedlings remained detectable four weeks after treatment. On-farm test locations with the two highest percentages of premature flowering had the lowest average daily minimum temperatures during the pretransplant period. Premature flowering was significantly increased at two of seven locations by removal of the perforated plastic plant bed covers two weeks compared to one week before transplanting. Floral induction of tobacco seedlings in controlled pretransplant environments was obtained by continuous 15°C temperature and 8 h photoperiods for 3 weeks.

Name thesis:degree_name

Ph. D.

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Agronomy

Department dc:contributor.department

Agronomy

Grantor dc:publisher

Virginia Polytechnic Institute and State University

Year dc:date.issued

1985

Author dc:creator

• Fowlkes, Donald James

Chair dc:contributor.committeechair

• Jones, James L.

Committee members dc:contributor.committeemember

• King, M.J.
• Wolf, D.D.
• Orcutt, David M.
• Semtner, Paul

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en_US

Handle dc:identifier.uri

http://hdl.handle.net/10919/54749

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/54749