Trinexapac‐Ethyl and Open‐Field Burning Maximize Seed Yield in Creeping Red Fescue

Abstract

Open‐field burning, an effective and economical practice for increasing seed yield in creeping red fescue (Festuca rubra L.), has been restricted in Oregon due to air quality and safety issues. The use of the plant growth regulator trinexapac‐ethyl [4‐(cyclopropyl‐α‐hydroxy methylene)‐3,5‐dioxocyclohexane carboxylic acid ethyl ester] (TE) was evaluated as a potential alternative to open‐field burning for maximizing yield in creeping red fescue over 4 yr. Fall and spring applications of TE in combination with residue management practices, open‐field burning and mechanical removal (flailing) of post‐harvest residue, were evaluated to determine potential effects on seed yield and dry matter partitioning. Spring TE applications in burn plots increased cumulative seed yield by 38% over the check. In flail plots, spring TE applications increased yield by 30 and 16% over the burn check for the first 2 yr, but no response was observed later. Open‐field burning was critical for maintaining high yields in the last 2 yr. Although late‐spring TE applications in flail plots resulted in cumulative yields comparable to those of burn check plots, yields were 34% lower than those of burn, TE spring‐treated plots. Fall TE applications had no consistent effect on seed yield. Therefore, neither spring nor fall TE applications are an effective alternative to replace open‐field burning in creeping red fescue seed production over the life of the stand if seed yield is to be maximized. Spring TE applications plus open‐field burning maximized seed yield and had the greatest harvest index, resulting in a more efficient crop.

Trinexapac-ethyl rate and application timing effects on seed yield and yield components in tall fescue

“…Similar effects of TE application on HI have been observed in tall fescue and in perennial ryegrass seed crops (Rolston et al, 2010;Chastain et al, 2014a). Crop canopy modification by TE enabled efficient partitioning of dry matter to seed yield in strong creeping red fescue (Zapiola et al, 2006(Zapiola et al, , 2014; however, improved carbon partitioning to seed alone could not account for the increased seed yield resulting from lodging control in perennial ryegrass .…”

“…Though widely used, a better understanding of how TE applications affect seed yield and yield characteristics in tall fescue would allow a greater use efficiency and economy. Zapiola et al (2006) found that a combination of TE and openfield burning of crop residues produced the highest seed yield in strong creeping red fescue. Partitioning of dry matter in the crop canopy was manipulated by this combination of residue removal practices after the previous seed harvest and application of TE in http://dx.doi.org/10.1016/j.fcr.2014.12.013 0378-4290/© 2015 Elsevier B.V. All rights reserved.…”

“…adopted for use as a lodging control agent in forage and turf grass seed production (Zapiola et al, 2006;Rolston et al, 2010). Reduction in stem length and lodging by TE resulted in increased seed yield in perennial ryegrass (Lolium perenne L.) seed crops (Borm and van den Berg, 2008;Rolston et al, 2010;Koeritz et al, 2013;Chastain et al, 2014a).…”

“…While the effects of TE on lodging control and seed yield in perennial ryegrass (Rolston et al, 2010;Koeritz et al, 2013;Chastain et al, 2014a) and strong creeping red fescue (Festuca rubra L. subsp. rubra) seed crops (Zapiola et al, 2006(Zapiola et al, , 2014 are well known, there have only been three investigations on these effects of TE in tall fescue. While these studies have reported that TE increased seed yield in tall fescue seed crops, there is limited information available on the effects of TE rate and application timing on seed yield and yield components across diverse lodging environments (Silberstein et al, 2000;Rolston et al, 2004;Chastain et al, 2014b).…”

Irrigation frequency and seasonal timing effects on perennial ryegrass (Lolium perenne L.) seed production

“…In other words, there does not seem to be a carry-over effect of prior irrigation applications manifested in following years with regard to seed yield or yield components. Seed yields in coolseason perennial grass seed crops are generally highest early in the life of the stand, with declining seed yields as that crop stand ages (Zapiola et al, 2006). Present recommendations for irrigation management offer conflicting crop water use (CWU) requirements for Oregon grass seed crops.…”