Grass seed yields increased with plant growth regulators and fungicides

Abstract

Seed yields of ryegrass and tall fescue have increased rapidly over the last seven years; the best farm yields are now reaching 3000 kg/ha, up from 2000 kg/ha. These increases are largely due to the adoption of technologies developed from research funded from grower crop levies and effective technology transfer programmes. The key technologies are (1) the adoption of trinexapac ethyl (TE), a plant growth regulator that blocks gibberellic acid biosynthesis and reduces lodging; and (2) new generation triazole and strobilurin fungicides that give improved disease control and extend the period that green leaf area is maintained on crops. Seed yield data from 10 ryegrass and 6 tall fescue trials with TE, and from 13 fungicide trials are presented. The average seed yield increase in tall fescue treated with 200 g TE/ha and ryegrass with 400 g TE/ha was 67% and 50% respectively. In fungicide trials, seed yields in forage perennial ryegrass were increased by 20% and in turf ryegrass by 42%. A survey of growers indicated 95% of ryegrass growers and 100% of tall fescue growers had adopted the use of TE three years after the commercial release of the product. Keywords: fungicides, plant growth regulators, ryegrass, seed yield, strobilurin, tall fescue, triazole, trinexapac

Plant growth regulators: a success story in perennial ryegrass seed crops

“…Seed yield increased at a maximum rate up to approximately 1.6 l/ha (400 g a.i./ha) followed by a decreasing rate response ( Figure 1) when relative seed yield data (untreated control equals 100%) from ten experiments were combined. These data build on those presented by Rolston et al (2004) where a similar response curve was shown for a single experiment. Increasing Moddus rates generally increased the number of seeds per spikelet at harvest which was directly related to seed yield ( Figure 2).…”

“…However grower adoption was limited. The introduction of trinexapac-ethyl (Moddus ® ), a foliar absorbed PGR, revolutionised grass seed yields in New Zealand with average seed yield increases of 50% common (Rolston et al 2004). These results are similar to those achieved by Hebblethwaite et al (1978) who recorded a 40% yield increase when lodging was prevented using wires.…”

“…Seed samples were machine dressed on a small-scale air-screen separator to achieve a 1 st Generation seed purity standard and converted to a yield/ha. Detailed methods and results have been reported for data prior to 2004 by Rolston et al (2004) Interaction trials In the 2007/08 season two interaction trials investigated the response of Moddus to spring nitrogen and closing date. The trials were located in mid-Canterbury.…”

“…The overall effect of Moddus is an increase in the number of seeds produced per spikelet (Chastain et al 2003;Rolston et al 2007a). In New Zealand, Moddus is applied to greater than 95 percent of ryegrass seed crops (Rolston et al 2004) at rates that range up to approximately 1.6 l/ha. However growers often comment on variable responses which appear to be related to differences in crop bulk at the time of Moddus application.…”

Effect of a Strobilurin-Containing Fungicide Applied at Two Timings on Seed Yield in Tall Fescue

“…Previously published literature has reported the benefits of strobilurin (azoxystrobin) fungicides in controlling stem rust and increasing seed yield in perennial ryegrass (Rolston et al, 2004; Pfender, 2006), but this information has not been previously available for tall fescue. While there are university recommendations and pesticide labels for the use of strobilurin‐containing fungicides for the control of stem rust in tall fescue, there are no previously published accounts of this fungicide increasing seed yield in tall fescue seed crops (Syngenta Crop Protection, 2013; Anonymous, 2013).…”