EVALUATION OF SEVERAL GROWTH REGULATORS FOR STIMULATING LOWBUSH BLUEBERRY (VACCINIUM ANGUSTIFOLIUM AIT.) RHIZOME PRODUCTION

B.A. Libby, J.M. Smagula
Two field studies were conducted to evaluate the effects of plant growth regulators on lowbush blueberry rhizome growth. In each study, sod strips 30 cm wide containing 30×91 cm treatment plots with buffers between were bordered by excavated sod strips, into which 10 cm layer of softwood bark mulch was added. Rhizomes grew into the mulch and were measured in response to treatments. In 2009, foliar applications of NAA [naphthaleneacetic acid, 2-(1-naphthyl)acetic acid], ethephon (2-chloroethylphosphonic acid), and prohexadione-Ca (prohexadione-calcium, calcium 3-oxido-5-oxo-4-propionylcyclohex-3-enecarboxylate), at two concentrations each, were made on 17 June when shoots were approximately 4 cm tall. Plants receiving prohexadione-Ca at 125 mg•L-1 produced almost three times as many rhizomes (9.9) as the control (3.6). NAA and ethephon applications were not effective. In 2011, the effects of timing of application and concentration on rhizome growth were assessed on treatment plots that received an application of prohexadione-Ca at one of two concentrations (125 and 250 mg L-1) on one of three dates (6 June, 15 June, 27 June). Plants receiving prohexadione-Ca at 250 mg•L-1 on 27 June produced the greatest number of rhizomes (14.6) and rhizome tips (16.4) per treatment plot. Plants receiving prohexadione-Ca at 250 mg•L-1 on any of three dates produced a greater number of rhizomes and rhizome tips per treatment plot than control plants; while plants receiving 125 mg•L-1 did not. Also, plants receiving either of the two concentrations (125 and 250 mg•L-1) on 27 June produced greater numbers of rhizomes and rhizome tips per treatment plot than control plants, while plants receiving either of the two concentrations on 6 June or 15 June did not. Therefore, prohexadione-Ca may be effective at improving rhizome growth of lowbush blueberry, but concentration and timing of application are critical for success.
Libby, B.A. and Smagula, J.M. 2014. EVALUATION OF SEVERAL GROWTH REGULATORS FOR STIMULATING LOWBUSH BLUEBERRY (VACCINIUM ANGUSTIFOLIUM AIT.) RHIZOME PRODUCTION . Acta Hort. (ISHS) 1017:497-504
http://www.actahort.org/books/1017/1017_62.htm
prohexadione-Ca, naphthaleneacetic acid, ethephon
English

Acta Horticulturae