TitleTrinexapac-ethyl rate and application timing effects on seed yield and yield components in tall fescue
Publication TypeJournal Article
Year of Publication2015
AuthorsChastain, T, Young, WC, Garbacik, CJ, Silberstein, TB
JournalField Crops Research
Volume173
IssueComplete
Pagination8 - 13
Date Published2015
KeywordsGrass seed crop production, Lodging, Schedonorus arundinaceus (Shreb.) Dumort. seed yield, Trinexapac-ethyl
Abstract

Trinexapac-ethyl (TE) has been used for lodging control and seed yield enhancement in several grass seed crop species but little is known about how this plant growth regulator (PGR) performs in tall fescue [Schedonorus arundinaceus (Shreb.) Dumort.]. The objective of this study was to determine how TE application rate and timing influences seed productivity over six diverse lodging environments in Oregon's Willamette Valley. Three field trials were conducted to examine TE effects on seed yield and yield components. Stem length, a key factor in lodging control, was reduced incrementally with increasing TE rate from 17% reduction at 200gTEha−1 to a maximum of 39% reduction at 600gTEha−1. Lodging was consistently reduced by TE but had no effect on above-ground biomass and paniclesm−2. Over environments, TE increased seed yield by an average 40% over the untreated control. However, TE rate or application timing did not differentially affect seed yield across environments. Increases in tall fescue seed yield attributable to TE were the result of increased seed numberm−2 and improved harvest index (HI), but not seed weight. A better understanding of TE-induced seed yield increases will aid in improving use efficiency and economy of this important PGR.