A new publicPicture1ation on nutrient management in perennial ryegrass seed crops has just been released by OSU’s grass seed production research and extension team.  The publication (EM 9086) is a product of many years of  field work in grass seed crops by the members of the research and extension team.  The nutrient management guide covers the impacts of application of nutrients on seed yield, seed yield components, crop growth and development, plant growth regulator use, pests, and others.  Extensive use of tables, figures, and appendices supplement this comprehensive work on perennial ryegrass nutrient management.

The publication can be accessed at the link below:

Perennial Ryegrass Grown for Seed (Western Oregon) EM 9086

Here’s  a new article from our research group on trinexapac-ethyl plant growth regulator (PGR) effects in perennial ryegrass seed crops that will be published in Field Crops Research.  This PGR is marketed as Palisade, Moddus, and several generic products.  The trials were conducted from 1998 to 2012 at OSU’s Hyslop Farm.

Figure 1.  Lodging in ryegrass.
Figure 1. Lodging in ryegrass.

The study reports several important findings:

  • Application of trinexapac-ethyl PGR reduced stem length and controlled lodging in perennial ryegrass across nine diverse lodging environments in the Willamette Valley of Oregon.
  • Trinexapac-ethyl PGR consistently increased seed yield and harvest index in perennial ryegrass regardless of the severity of lodging.
  • Timing trinexapac-ethyl applications between BBCH stages 32 and 51 produced the best seed yield results.
  • Seed yield increases resulting from trinexapac-ethyl application were attributable to a greater number of seeds spikelet-1 (seed number) and improvements in seed set.


Click on the citation below to go to the article:

Chastain, T.G., W.C. Young III, T.B. Silberstein, and C.J. Garbacik.  2014.  Performance of trinexapac-ethyl on seed yield of Lolium perenne in diverse lodging environments.  Field Crops Research 157:65-70.


Thomas G. Chastain

Tillers, rhizomes, and stolons are three types of branches produced by grass plants.  All are stems that branch at some point from the crop’s mainstem or from other stems.

Figure 1. Kentucky bluegrass plant (T.G. Chastain photo).

The tiller is an above-ground branch on a grass plant.  Tillers are an important component of the crop’s shoot system and through carbon capture and partitioning, contribute to seed yield.  As a tiller grows and develops, additional tillers can form in the leaf axils of that tiller.  All grasses produce tillers. Continue reading

Thomas G. Chastain

Grass seed crops are biologically inefficient in the production of seed.  Many flowers are produced by these grasses yet relatively few of the flowers become seed, thus the potential seed yield may be many times greater than the actual seed yield harvested.  Losses due to inadequate pollination and fertilization, abortion during seed development, and seed shattering all contribute to the relative low numbers of seed that are harvested compared to the crop’s yield potential.

Ryegrass floret

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Thomas G. Chastain

Why is lodging important in grass seed crops?

Under certain conditions, the tiller cannot support the weight of the developing inflorescence and seed. The tiller lodges or falls to the ground, especially when there are high levels of nitrogen fertilizer and soil moisture present (Fig. 1). Both conditions are common in Oregon’s commercial grass seed production fields in the spring.  But will that be the case in spring 2013?

The winter months of January through March 2013 have been the 2nd driest winter period on record at Corvallis with only 6.28 inches recorded.  Can we expect more of the same dry weather during spring?  No one can say for sure, but an examination of weather records for the past 124 years reveals that when precipitation is very low (50% or less of the 16.02 inch normal) in January through March, the following April through June period averages 5.78 inches or near normal rainfall (normal is 5.83 inches). 

Despite the very dry weather that has been recorded to date, there may still be enough rainfall present in coming months to make lodging a problem for local seed growers.

Figure 1. Lodging in ryegrass. (T.G Chastain photo)

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Thomas G. Chastain

Willamette Valley seed producers have endured yet another cold and wet spring.  Seed growers are now looking forward to the pleasant dry and warm summer weather that area is well known for to aid in harvest and other field operations.  This spring’s weather was both colder and wetter than the long-term averages for the locale.  And this combination of cold and wet weather in spring is part of a trend that has been evident for the past four years.

Figure 1. Spring monthly average temperatures at Corvallis for the past four cropping years.

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