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Irrigation and Trinexapac‐Ethyl Effects on Seed Yield in First‐ and Second‐Year Red Clover Stands
Author(s) -
Anderson Nicole P.,
Chastain Thomas G.,
Garbacik Carol J.
Publication year - 2016
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj2015.0513
Subject(s) - irrigation , yield (engineering) , field experiment , agronomy , horticulture , productivity , mathematics , biology , materials science , metallurgy , economics , macroeconomics
Irrigation and trinexapac‐ethyl (TE) [4‐(cyclopropyl‐α‐hydroxymethylene)‐3, 5‐dioxo‐cyclohexanecarboxylic acid ethylester] plant growth regulator (PGR) have been reported to enhance seed yield in red clover ( Trifolium pratense L.). This study examined the interaction of irrigation and TE on seed productivity in first‐and second‐year stands in western Oregon (OR). Two field trials were established and followed over a 2‐yr period (2012–2013, 2013–2014). Treatments consisted of an untreated control, and 140, 280, 420, 560, and 700 g a.i. ha −1 TE PGR applied at BBCH growth stages 32 and 51, and in split applications at BBCH 32 + 51. A single irrigation (100 mm) applied at BBCH 55 increased seed yield and weight in first‐and second‐year stands by 13 and 5%, respectively. Seeds m −2 increased nearly 10% with irrigation in both first‐and second‐year stands in 2013 but not in 2014. Application of TE at BBCH 32 increased seed yield by 13.8% in second‐year stands, except at the 700 g a.i. ha −1 rate, and had no effect or reduced seed yield in first‐year stands. Seed weight was reduced by TE at all timings and reductions were proportional to the rate of application. Seeds m −2 increased in first‐year stands with TE rates ≥280 g a.i. ha −1 and ≥420 g a.i. ha −1 in 2012 and 2013, respectively, and with all rates in second‐year stands. There was no interaction between irrigation and TE in any year. First‐ and second‐year stands will likely benefit from irrigation; however, TE only increased seed yield in second‐year stands. Core Ideas Irrigation and trinexapac‐ethyl independently increase red clover seed yield but there is no interaction between the two. Red clover seed yield is enhanced by increasing seed weight with irrigation whereas seed weight is reduced with trinexapac‐ethyl. Irrigation increases seed yield in first‐and second‐year stands but trinexapac‐ethyl only increases seed yield in second year stands.