Investigating the Prospect of Fine Fescue Turfgrass Seed Production in Minnesota

A THESIS SUBMITTED TO THE FACULTY OF THE UNIVERSITY OF MINNESOTA BY

David Rodriguez Herrera

IN PARTIAL FULFILLMENT OF THE REQUIERMENTS FOR THE DEGREE OF MASTER OF SCIENCE

Dr. Nancy Ehlke and Dr. Eric Watkins

January 2020

Acknowledgements

I want to give thanks to my advisors Dr. Nancy Ehlke, Dr. Eric Watkins, along with my committee member Dr. Carl Rosen. Their guidance was essential in this project.

I also want to acknowledge Donn Vellekson, Andrew Hollman, Dave Grafstrom, Garrett

Heineck, and the entire turf team for their support. None of this would have been possible with the generous financial support from the Minnesota Department of Agriculture, the

University of Minnesota, and the Minnesota Turf Seed Council. Lastly, I would like to thank my parents Eberardo Rodriguez and Evodia Herrera.

Dedication

I would like to dedicate this thesis to the hard-working turfgrass seed producers of northern Minnesota.

Executive Summary

The fine fescues (Festuca spp.) are a group of specialized cool-season turfgrasses that have consistently demonstrated average to exceptional quality across a range of minimally managed environments. Introducing commercial seed production of these turfgrasses in northern Minnesota is being considered because evidence suggests that consumers strongly desire and are willing to pay for the sustainable characteristics they possess. Fine fescue turfgrass seed has been historically difficult to produce successfully in Minnesota due to low yields and noxious weed infestations, but steady improvements in germplasm have encouraged agronomists to develop improved fine fescue seed production practices. Nitrogen fertility and safe herbicide use were investigated in fine fescue field experiments across Minnesota under the objective of determining whether commercial seed production is viable. Fertility management trials were established in three sites in Minnesota; St. Paul, Becker, and Roseau. Five taxa of fine fescue were tested: Chewings fescue (Festuca rubra L. ssp. commutata) ‘Windward’, strong creeping red fescue (Festuca rubra L. ssp. rubra) ‘Cindy Lou’, hard fescue (Festuca brevipila T.)

‘MNHD’, sheep fescue (Festuca ovina L.) ‘Quatro’, and slender creeping red fescue

(Festuca rubra L. ssp. litoralis) ‘Shoreline’. Entries seeded in 2016 and grown for two seasons. Stands were managed under five nitrogen fertility management strategies, two fall-applied treatments of high (89.6 kg ha-1) and low (44.8 kg ha-1), and two fall and spring treatments of split high (44.8 kg ha-1) and split low (22.4) kg ha-1, and a control.

All entries, except strong creeping red fescue ‘Cindy Lou’, had at least one seed yield meaningfully influenced by a nitrogen treatment. However, these seed yields were not affected consistently or in any pattern in any specific year and location combination.

iii

Hard fescue ‘MNHD’ had seed yields that were increased by an average of 250 kg ha-1 from the high and split high nitrogen treatments in two locations, Roseau and St. Paul, during the first harvest year compared to the control. Previous nitrogen fertility experiments showed that certain taxa and cultivars of fine fescues had a seed yield response from spring nitrogen applications of approximately 50 kg ha-1. Harvest index of all fine fescues, except strong creeping red fescue ‘Cindy Lou’ was also influenced in at least one year-location combination, similar to seed yield, not in any pattern or meaningful way. Thousand seed weight, panicle weight, spikelets per panicle, florets per panicle, and panicle density were variables measured in the 2018 growing season but ultimately not affected by any nitrogen fertility management treatment. The herbicide safety trial was established on Magnusson Research Farm using hard fescue ‘MNHD’. It was seeded in both 2015, from which two harvests were taken, and 2017, from which only one harvest was taken. Herbicide treatment applications consisted of effective turfgrass seed production herbicides clethodim, fluazifop, mesotrione, dicamba, 2,4–D amine, and a combination 2,4–D amine and dicamba, and a control. Seed yield, thousand seed weight, and germination of hard fescue ‘MNHD’ was severely reduced by the clethodim treatment in 2016 and 2018, both of which were first-year establishments.

None of the herbicide treatments influenced hard fescue ‘MNHD’ in the 2016 growing season, the second year of the 2015 seeding. Past investigations have provided evidence that fine fescue’s susceptibility to certain herbicides can change depending on the age of the stand. Based on these field experiments fine fescue seed yields range between 500 and 1000 kg ha-1 in Minnesota. These seed yields reflect the averages of the competing regions of Oregon and Western Canada, and were achieved with and without the use of

supplemental nitrogen applications. Therefore, the use of supplemental nitrogen may not be required to obtain these seed yields for a range of fine fescue taxa. Hard fesuce seed yield ‘MNHD’ may benefit from additional nitrogen amendments in first-year stands.

Furthermore, ensuring the commercial value of fine fesuce seed harvests can be achieved through the application of most turfgrass seed production herbicides without damaging seed yield, weight, or germination.

Table of Contents

Acknowledgements……………………………………………...………………………..i

Dedication…………………………………………………………………..…………….ii

Executive Summary………………………………………………………………..……iii

List of Tables……………………………………………………………………….……ix

List of Figures…………………………………………………………..………………..xi

Chapter 1: Overview of the Fine Fescues

Introduction…………………………………………………………….………….1

Classification and Evolutionary History………………………………….……….2

Cytogenetic Classification………………………………..……………………….2

Physical Description……………………………………………………..………..3

Adaptation for Present Turfgrass Use………………..……………………………4

Disadvantages in the Fine Fescues……………………………….……………….8

Breeding…………………………………………………………………….……10

Economic Value…………………………….……………………………………11

Consumer Attitudes Toward Low-Input Turfgrasses……………………………13

Seed Production Regions of the World…………………………………..………14

Oregon in the Northwestern United States……………………....………………15

Peace River Region in Northwestern Canada……………………………………16

Denmark………………………………………………………………….………17

Northern Minnesota……………………………………………………...………17

Post-Harvest Residue Management Trials from Oregon and

Canada……………………………………………...…………………………….18

Nitrogen Fertilizer Application Rates and Timing………………………………21

Herbicide Use for Seed Purity……………………………………..…….………24

Summary and Hypotheses……………………………………………..…………26

Chapter 2: Seed Yield and Components of Five Fine Fescue Taxa Under Different

Nitrogen Fertility Practices

Introduction………………………………………………………………...…….28

Materials and Methods………………………...…………………………………30

Results……………………………………………………………………………35

Rainfall, Temperature, and Residual Soil Nitrate………………………..………35

Harvest Index, Seed Weight, and Seed Yield Components……………………...36

Yield……………………………………………………………………………...36

Comparing Experimental Environments Broadly………………………………..37

Discussion…………………………………………..……………………………38

Rainfall, Temperature, and Residual Soil Nitrate………………………………..38

Harvest Index, Seed Weight, and Seed Yield Components……………………...40

Yield……………………………………………………………………...………41

Comparing Experimental Environments Broadly………………………………..44

Conclusions and Implications.……………….…………………………………..45

Chapter 3: Seed Yield, Weight, and Germination of Hard Fescue (Festuca brevipila

T.) ‘MNHD’ Under Different Turfgrass Seed Production Herbicides

Introduction………………………………………………………………………66

vii

Materials and Methods…………………………………………………………...69

Results…………………………………………………………………………....72

Discussion and Conclusions…..…………………………………………………73

Bibliography…………………………….………………………………………………89

viii

List of Tables

Chapter 2

Table 1. Fine fescue taxa, common name, and respective cultivar used in the fertility experiments ……………………………………………………………………………...49

Table 2. Nitrogen treatments used in the field experiments. Key for figures 1 through 6 and for tables 6 through 11…………………………………………………..…………..50

Table 3. Dates of nitrogen treatment applications (Date) across the six experimental environments and the number of days elapsed (Rain) before a rain event occurs………………………………………………………………………….………....51

Table 4. Soil nitrate content, precipitation, and maximum and minimum mean temperature data across the six experimental environments. Precipitation and temperature are measured March through July…………………………………..………………..…..52 Table 5. Analysis of variance for yield, harvest index, thousand seed weight, panicle weight, spikelets panicle-1, florets spikelet-1, and panicles m-2 across six experimental environments. Significance for these response variables at the nitrogen treatment(A), taxa(B), and interaction(A*B) is depicted.………..……………………………………..53

Table 6. Seed yield, harvest index and thousand seed weight of five taxa of fine fescue in

St. Paul 2017….………………………………………………………..………………...60

Table 7. Seed yield, harvest index and thousand seed weight of five taxa of fine fescue in

Becker 2017……………………………………………………………..…………….…61

Table 8. Seed yield, harvest index and thousand seed weight of five taxa of fine fescue in

Roseau 2017…………………………………………………………..……………….…62

Table 9. Seed yield, harvest index, thousand seed weight, panicle weight, spikelets panicle-1, florets panicle-1, and panicles m-2 of five taxa of fine fescue in St. Paul

2018……...…………………………………………………………….…………………63

Table 10. Seed yield, harvest index, thousand seed weight, panicle weight, spikelets panicle-1, florets panicle-1, and panicles m-2 of five taxa of fine fescue in Becker

2018…………………………………………………………………….……………...…64

Table 11. Seed yield, harvest index, thousand seed weight, panicle weight, spikelets panicle-1, florets panicle-1, and panicles m-2 of five taxa of fine fescue in Roseau

2018…………………………………………………………………….………...………65

Chapter 3

Table 1. The six herbicides used in the field experiments. Trade name, active agent, herbicide class, group, mode of action, and target pest are described.……..……………77

Table 2 Listed are the seven herbicide treatments used in the field experiments.

Chemical, application rate, and percent surfactant are described. Treatments one through five consist of a single herbicide while treatment six is a combination of 2,4–D amine and

Clarity. Treatment seven was a control application of no herbicide.……………………78

Table 3. Analysis of variance for yield, thousand seed weight, and percent germination for the three experimental environments.………………………………………………..79

List of Figures

Chapter 2

Figure 1. Yield of Five Fine Fescue Taxa and Cultivars in St. Paul 2017 Under Different

Nitrogen Rates…………………………………………………………………………..54

Figure 2. Yield of Five Fine Fescue Taxa and Cultivars in St. Paul 2018 Under Different

Nitrogen Rates.…………………………………………………………………………..55

Figure 3. Yield of Five Fine Fescue Taxa and Cultivars in Becker 2017 Under Different

Nitrogen Rates…………………………………………………………………………..56

Figure 4. Yield of Five Fine Fescue Taxa and Cultivars in Becker 2018 Under Different

Nitrogen Rates…………………………………………………………………………..57

Figure 5. Yield of Five Fine Fescue Taxa and Cultivars in Roseau 2017 Under Different

Nitrogen Rates…………………………………………………………………………..58

Figure 6. Yield of Five Fine Fescue Taxa and Cultivars in Roseau 2018 Under Different

Nitrogen Rates………………………………………………………………………….59

Chapter 3

Figure 1. Herbicide Effect on Seed Yield of Hard Fescue ‘MNHD’

2016………………………………………………………………………………………80

Figure 2. Herbicide Effect on Thousand Seed Weight of Hard Fescue ‘MNHD’

2016…………………………………………………..……………………..……………81

Figure 3. Herbicide Effect on Germination of Hard Fescue ‘MNHD’

2016……..…………………………………………………………………..……………82

Figure 4. Herbicide Effect on Seed Yield of Hard Fescue ‘MNHD’

2017………………………….…………………………………………………...………83

Figure 5. Herbicide Effect on Thousand Seed Weight of Hard Fescue ‘MNHD’

2017……………………………………………………………………………………....84

Figure 6. Herbicide Effect on Germination of Hard Fescue ‘MNHD’

2017……………………………...…………………………………………………….…85

Figure 7. Herbicide Effect on Seed Yield of Hard Fescue ‘MNHD’

2018……………………………………………………..………………………………..86

Figure 8. Herbicide Effect on Thousand Seed Weight of Hard Fescue ‘MNHD’

2018…….……..……………………….…………………………………………………87

Figure 9. Herbicide Effect on Germination of Hard Fescue ‘MNHD’

2018...... …………………………………………………………………88

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Chapter 1: Overview of the Fine Fescues

Introduction

In the United States there are an estimated 12 million hectares of turfgrass existing in sports fields, home lawns, recreational green spaces, airports, reclamation sites, and golf courses (Bertin et al. 2009). Natural resource conservation continues to improve and turfgrass researchers are participating by addressing issues in turfgrass science like nutrient and water use efficiency, heat and drought tolerance, and disease resistance. Turfgrasses may be mischaracterized as being unsustainable due to perceived requirements of excessive fertilizer and irrigation inputs (Hall 2009). Fine fescues, specialized turfgrasses in the Festuca genus, are widely known among turfgrass science researchers and enthusiasts for their enhanced sustainability (Beard 2013, Bonos and

Huff 2013). These turfgrasses have been shown to persist under minimal maintenance in a variety of turfgrass applications and inherently possess low-maintenance characteristics that are sought by consumers, however they remain anonymous among the general public

(Hugie et al. 2012). Turfgrass researchers and breeders consider these grasses as low- maintenance because past research and documented historical use have demonstrated their tolerance to saline and acidic soils (Zhang et al. 2013), cold temperatures, moderate shade stress (Bonos and Huff 2013), heavy metal-contaminated soils (Brown and

Brinkman 1992), moderate drought conditions (Watkins et al. 2010), and certain disease and weed pressures (Bertin et al. 2009, Bonos and Huff 2013). This review highlights fine fescue evolutionary history, morphology, genetics, historical and current use, breeding, consumer preferences, and seed production. All this is consolidated to explore the question of whether commercial seed production is possible in northern Minnesota.

Classification and Evolutionary History

Five principal taxa are considered fine fescues and used as turfgrass: hard fescue

(Festuca brevipila T.), sheep fescue (Festuca ovina L.), Chewings fescue (Festuca rubra

L. ssp. commutata), strong creeping red fescue (Festuca rubra L. ssp. rubra), and slender creeping red fescue (Festuca rubra L. ssp. litoralis) (Cook 2017). While there are other fine-leaved taxa in the Festuca genus, commercial seed production and the ability to form a manageable turfgrass are two qualities that distinguish the fine fescues as a specialized group.

The Festuca genus first appeared 13 million years ago in central Europe and began to diversify in continental climates in the last 10.5 million years (Inda et al. 2008).

Today, the over 450 taxa of the Festuca genus are divided into two phylogenetic groups, fine-leaved and broad-leafed (Clayton 1986, Beard 2013 & Torrecilla and Catalan 2002).

Festuca exists worldwide in temperate and continental zones, but the fine fescues are mostly localized to the colder and high latitude regions of the world (Beard 2013). The fine fescues are naturalized in North America; estimates suggest they arrived three centuries ago in a 3 to 10 million-year migration to the continent (Beard 2013).

Cytogenetic Classification

Phylogenetic research using internal transcribed DNA sequences describe two groups within the fine fescue taxa, the sheep fescue aggregate and the red fescue aggregate (Inda et al. 2008, Torrecilla and Catalan 2002, Bonos and Huff 2013). The sheep fescue aggregate includes Festuca brevipila T. and Festuca ovina L., while the red fescue aggregate includes Festuca rubra L. ssp. commutata, Festuca rubra L. ssp. rubra,

Festuca rubra L. ssp. litoralis. The similar physical appearance between and within the two groups makes classification difficult (Beard 2013).

Huff and Palazzo (1998) described the fine fescues as having a haploid of seven chromosomes and a ploidy range of tetraploid to octoploid. In the sheep fescue aggregate, hard fescue has 42 chromosomes and is a hexaploid while sheep fescue has 28 chromosomes and is a tetraploid. In the red fescue aggregate, Chewings fescue and slender creeping red fescue both have 42 chromosomes and are hexaploid. Strong creeping red fescue has 56 chromosomes and is an octoploid. This cytology research assisted accurate classification attempts and breeding efforts for the taxa (Huff and

Palazzo 1998). Correctly classifying these taxa in a turfgrass setting helps determine which cultural management practices to use in turfgrass environments (Bonos and Huff

2013).

Physical Description

The one to three millimeter diameter of fine fescue turfgrass leaves is a hallmark morphological trait. Despite their similar appearance, adaptation variation within the fine fescues can be explained by ploidy differences, rhizomatous or bunch-type growth, response to cultural amendments and environmental stress, or leaf morphology (Bonos and Huff 2013). In the sheep fescue aggregate, both sheep fescue and hard fescue are bunch-type grasses, meaning that they do not produce rhizomes or stolons but rather their tillers project upward and outward. Chewings fescue is also a bunch-type grass but within the red fescue aggregate. Slender creeping red fescue and strong creeping red fescue, also a part of the red fescue aggregate, are both rhizomatous as their names imply (Bonos and

Huff 2013).

Taxa in the red fescue aggregate can be distinguished from the taxa in the sheep fescue aggregate by the fused leaf sheath present in the red fescues and by the overlapping leaf sheath present in the sheep fescues (Ruemmele et al. 2003).

Furthermore, red fescue taxa typically will have wider leaves than sheep fescue taxa, however differences among breeding populations can make this distinguishing feature unreliable (Schmidt et al. 1974, Bonos and Huff 2013).

Accurately distinguishing taxa within the sheep fescue aggregate using morphological methods relies on the sclerenchyma tissue of the leaf blade. Sheep fescue will have cells with a uniform thickness and even pattern while hard fescue will have interrupted cells with uneven thickness. Chewings fescue can be distinguished from strong and slender creeping red fescue by the bunch type growth habit present. Strong creeping red fescue will produce multiple extending rhizomes, while slender creeping red fescue will produce fewer and less extensive rhizomes (Meyer and Funk 1989, Aiken and

Darbyshire 1990, Wilkinson and Stace 1991). Recently, the use of chloroplast genetic markers has been identified as a possible tool for taxon identification (Qiu et al. 2019).

Adaptation for Present Turfgrass Use

Fine fescues may be used in mixtures with other cool-season turfgrasses or in mixtures consisting of only fine fescues. One early-recorded use of fine fescues as a turfgrass dates to the 16th century in Scotland where they were used in non-mowed roughs on golf courses (Beard 2002). Modern use of the fine fescues can be found mostly in turfgrass shade-mixes where they complement other turfgrasses with their improved shade tolerance and low fertility requirements. Use in sports fields, mainly golf courses is limited however. There are an estimated 60,000 hectares of maintained turf in the US golf

courses; roughly, 3% of these maintained acres are comprised of fine fescues (Lyman et al. 2007).

In field experiments fine fescues have been consistently described as low-input turfgrasses. They have been tested in a range of environments like golf fairways, home lawns, highway roadsides, and difficult soils. Watkins et al. (2010) tested 17 seldom used golf fairway taxa in a two-year study under low-input conditions that consisted of only one additional irrigation incidence after turfgrass plot establishment and one subsequent nitrogen fertilizer application after the initial establishment fertilizer was applied.

Furthermore, artificial traffic stress was applied to the plots with a 454 kg traffic golf cart in regular intervals during the months of May through September. The traffic stress was applied to two turfgrass mowing heights, 1.90 or 2.54 cm. Quality was assessed by ratings taken on a one to nine scale. Chewings fescue cultivar ‘Jamestown II’ and sheep fescue cultivar ‘Quatro’ produced average quality ratings in the first year after establishment and higher than average quality in the second year. Similar cool-season turfgrass species like ‘Award’ Kentucky bluegrass (Poa pratensis) and ‘Corgi’ tall fescue

(Festuca arundinacea Schreb.) failed to produce average or above average quality ratings under these same low-input conditions (Watkins et al. 2010).

Fine fescue taxa are excellent low-input turfgrasses that have been recommended for use in residential lawns. Watkins et al. (2014) tested multiple cultivars of hard fescue, sheep fescue, and Chewings fescue, and other cool-season turfgrass taxa in no- maintenance turfgrass plots across eight locations in the central United States. This experiment tested these cool-season grasses in minimal conditions across a diverse range of soils and climates. After an initial irrigation and starter fertilizer application at

establishment, plots were not maintained any further. Plot uniformity, density, and color ratings on a one to nine scale were used to assess turfgrass quality, in this study a rating of five was considered acceptable turfgrass quality. Collectively, Chewings fescue and hard fescue cultivars performed adequately in most or all locations under these low-input conditions after producing quality ratings at or above five in two years following establishment.

Another similar low-input study described the fine fescues’ ability to survive in low-input conditions and suppress weeds. Bertin et al. (2009) evaluated turf quality, seedling vigor, and weed suppression ability of 78 fine fescue cultivars in a low-input environment in Ithaca, New York from 1999 to 2002. After the initial establishment in

1998 which involved some starter fertilizer and irrigation, plots received no additional amendments and were mowed to maintain a height of 1.9 cm. The site featured an

Arkport fine sandy loam soil type that was slightly acidic at 5.9 on the pH scale. Organic matter was measured to 3.2%. Many of the top performing cultivars had a general turfgrass quality range of between 5.1 and 5.6, which is just under the acceptable range of

6 according the National Turfgrass Evaluation Program. This is remarkable especially when considering that plots received no additional fertilizer or irrigation for three years after the seeding establishment. Several cultivars also had acceptable seedling vigor ratings of 6 or above, seedling vigor was assessed by determining total ground cover one year after establishment. Additionally, Chewings fescue and strong creeping red fescue were taxa identified as having the most cultivars with the highest weed suppression ability of between 70 and 80%, weed suppression was measured by assessing weed infestations in individual plots. Bertin et al. (2009) noted that higher turfgrass quality

ratings in 1999 despite lower than average rainfall that year was evidence of fine fescues’ ability to tolerate drought and require minimal irrigation.

Fine fescue turfgrasses are recommended for use in highway roadsides in cold climates because in field experiments they have demonstrated a degree of salt tolerance.

Moreover, their slow-growing nature reduces the need for frequent maintenance in the form of mowing. Fine fescues also have excellent freezing tolerance, which is helpful for reducing freezing damage and also reduces replanting each spring (Loren et al. 2012).

Friell et al. (2012) conducted a roadside turfgrass study using several taxa of cool- season grasses in two high traffic sites in Minnesota. The objective was to measure how well these taxa perform in a saline soil environment in real world conditions. Ratings of turf establishment and salt stress quality were taken in the fall during establishment and in the following spring, respectively. Slender creeping red fescue cultivar ‘Shoreline’, and strong creeping red fescue cultivar ‘Navigator’, were reported as having the highest salt stress tolerance in a suburban roadside (Friell et al. 2012). Salt tolerance has also been reported in vitro. Zhang et al. (2013) tested multiple fine fescue cultivars in two controlled saline environments, a germination agar plate and a hydronic medium.

Multiple physiological parameters like germination, fresh and dry tiller weight, and root dry weight were used to measure salt stress. ‘Slender’ strong creeping red fescue showed excellent salt tolerance compared to other fine fescue taxa.

Tolerance to heavy metals has been reported in fine fescue turfgrass taxa.

Ecotypes tolerant of metal-laden soils have been discovered in former mine sites around the world. Huff and Wu (1985) grew individual tillers from ‘Merlin’ and ‘Stirling’ red fescue (Festuca rubra L.), two populations found growing near mine sites in Scotland

and England, respectively, in a metal-laden solution and measured root length compared to a control solution to determine a tolerance index. They reported that these two ecotypes possessed greater zinc and copper tolerances, respectively, than the ‘Pennlawn’ the control cultivar used. In a similar investigation, Brown and Brinkman (1992) tested wild sheep fescue accessions from lead contaminated soils in the Eifel Mountains in

Germany in a metallic solution and measured lead content in various tissues. These sheep fescue ecotypes acquired more lead in their areal shoots and roots when compared to other accessions of the same taxa in nearby areas (Brown and Brinkman 1992).

Disadvantages in the Fine Fescues

As specialized as these taxa are, fine fescue turfgrasses are not suitable for a range of environments where frequent physical stress (e.g. sports fields), intense heat, and certain disease pressures are present.

Minner and Valverde (2005) subjected five popular cool-season turfgrass taxa, including a fine fescue, to two levels of simulated traffic stress and measured turfgrass quality over a period of two years. The traffic stress was simulated using a cleated roller and quality ratings were given on a one to ten scale. Under high traffic frequency stress and low traffic frequency stress strong creeping red fescue cultivar ‘Cindy’ performed poorly in overall turfgrass cover density and quality when compared to the rest of the taxa used. Chen et al. (2013) subjected several fine fescue taxa and cultivars to artificial golf cart stress and simulated foot traffic on irrigated plots established with a starter fertilizer. The two types of traffic stress significantly reduced uniformity, density cover and turf canopy vigor in all the fine fescue taxa and cultivars, though some cultivars, like

‘Radar’ Chewings fescue and ‘Beacon’ hard fescue, demonstrated moderate tolerance to

physical stress. Grimshaw et al. (2017) applied artificial wear and traffic stress to individual accessions of hard, Chewings, and strong creeping red fescue for two growing seasons. Average quality for these three taxa were in the 4 to 4.9 range out of 10 revealing that no accessions had excellent tolerance to these two types of physical stress.

Moreover, turfgrass scientists have noted poor traction on fine fescue turfgrass taxa and consider them unsuitable for intensive use on sports fields (McNitt & Waddington 1992,

Meyer 1986).

Tolerance to heat stress is another noted weakness of fine fescue turfgrass taxa and often are not recommended for use in environments with higher temperature ranges

(Ruemmele et al. 2003, Bonos and Huff 2013). Wang et al. (2017) simulated drought and heat stress in several fine fescue taxa and cultivars in growth chamber experiments and then measured turf quality, electrolyte leakage, and photochemical efficiency. Hard fescue and sheep fescue taxa appeared to be the most drought and heat tolerance, while

Chewings fescue taxa were the most sensitive to both types of stress. Broadly, Wang et al. (2017) concluded that fine fescues turfgrass taxa are more susceptible to heat stress than drought stress.

Fine fescue turfgrasses have susceptibly to a range of diseases, this is noted as being a weakness where these disease pressures are present. Not all fine fescues are equally affected by the same diseases, there exists variability in the degree that certain diseases affect certain taxa and cultivars (Ruemmele et al. 2003). Fraser et al. (1998) inoculated fine fescue taxa and with wild isolates of summer patch (Magnaporthe poae).

Across all taxa, there was variation in the disease severity in artificial inoculations compared to disease severity in natural settings. Summer patch was particularly

devastating to hard fescue and slender creeping red fescue while strong creeping red fescue and Chewings fescue were not as severely affected (Fraser et al. 1998).

Conversely, disease trials of red thread (Laetisaria fuciformis), by Rutgers University showed that nearly all strong creeping red fescue cultivars have a high degree of susceptibility (Grimshaw et al. 2016). As for Chewings fescue, there was variability to the degree of severity of red thread in all the cultivars tested. Moreover, Leaf spot

(Bipolaris spp.) affected strong creeping red fescue more than hard fescue, which was largely unsusceptible. Collectively Chewings fescue, hard fescue, and slender creeping red fescue demonstrated broad resistance to dollar spot (Sclerotinia homeocarpa), while only some strong creeping red fescue cultivars had moderate resistance (Han et al. 2003,

Shortell et al. 2005, Tate et al. 2012). This variation of susceptibility to a range of diseases leaves improvements to be made in fine fescue taxa, however it could also provide an advantage when used in mixes in turfgrass settings.

Breeding

Fine fescue turfgrass taxa are generally considered self-incompatible and therefore breeders rely on crosses for germplasm improvements. As a whole, current breeding objectives in fine fescue turfgrass taxa include improved drought and heat tolerance; improved ability to persist in infertile, metal-contaminated, or saline soils; improved resistance to weed and disease pressures; higher seed yield, and enhanced ability to quickly form a dense low-maintenance turfgrass profile with other turfgrass taxa (Meyer and Funk 1989, Bonos and Huff 2013, Ruemmele et al. 2003).

Challenges of improving fine fescue turfgrasses can be traced back to differences in ploidy, variation in sexual nature like pollen shedding frequency and time, and the high

degree of self-incompatibility (Bonos and Huff 2013, Ruemmele et al. 1995, Huff et al.

1998). Fine fescue taxa are outcrossing and therefore heterogeneous, this can make it difficult to breed since combining useful alleles becomes more unlikely. Furthermore, the increased ploidy in fine fescue taxa further increases heterogeneity. Breeders may find useful wild germplasm from established greens scattered throughout cool climates in

North America and Europe, or from germplasm banks where accessions are recorded and maintained (Rognli et al. 2010 & Ruemmele et al. 1995). Finding accessions that evolved adapted in minimal conditions may result in the discovery of useful traits that could be incorporated into already existing cultivars.

Compared to well-known turfgrass taxa, the fine fescues have fewer available cultivars for use and generally there are less resources dedicated to their development as turf taxa. This has resulted in negative implications for consumers who seek low-input turfgrasses at an affordable price. Furthermore, price and availability of these turfgrasses are unstable, however there is evidence that demand is increasing rapidly as environmental concerns become more prevalent in the 21st century (Ruemmele et al.

1995 & Meyer & Funk 1989).

Economic Value

The price of fine fescue seed depends on supply, demand, certification, quality, and region of origin. When combined, these factors make seed prices change frequently.

Notably, price variation is considerable within just a few years, making it challenging to make direct comparisons between regions and years. In Oregon between 2014 and 2016 the price of red fescue and Chewings fescue was estimated to be between $2.20 and

$2.31 USD per kg. Just a few years earlier between 2008 and 2011 with the same two

taxa prices were estimated to be between $1.43 and $1.98 dollars per kg USD (Oregon

Agripedia 2012, 2017).

Hard fescue seed production between 2014 and 2016 in Oregon was about a tenth of the total Chewings and red fescue production, but saw a higher average in prices over these three years; this might have been due to the limited production. Yields between these three years in Oregon for these three taxa range from 1050 to1250 kg ha-1 for red fescue, 1100 to 1300 kg ha-1 for Chewings fescue, and 900 to1100 kg ha-1 for hard fescue

(Oregon Agripedia 2012, 2017).

In Canada, it has been historically cheaper to produce red fescue seed due to reduced land costs when compared to Oregon (Nancy J. Ehlke, personal communication).

In a period from 2005 to 2014, a range of $.59 to $1.25 per kg USD of what was paid to red fescue growers with certified seed being about five cents more. This is about half of the price of seed grown in the United States.

Kentucky bluegrass and perennial ryegrass (Lolium perenne) are two similar cool- season turfgrass taxa that compete with the fine fescues for the total numbers hectares that are dedicated to turfgrass seed production, mainly in Oregon. Kentucky bluegrass seed has a higher market price of about $2.51 to $3.02 per kg USD compared to perennial ryegrass which is about $1.76 per kg USD. However, there are between 90,000 to 110,00 total hectares of perennial ryegrass seed production, which exceeds Kentucky bluegrass seed production of only 4,850 to 7,200 hectares. Perennial ryegrass seed yields are in the

1400 to 1600 kg ha-1 range while Kentucky bluegrass seed yields are in the 1000 to 1200 kg ha-1 range (Oregon Agripedia 2012, 2017).

Oregon has the advantage of selling fine fescue seed domestically resulting in lower transport costs and no import tariffs. While seed yields are doubled in Oregon, it is more expensive to produce there due to higher land costs. Canada has lower average seed yields but produces significantly more red fescue seed and at a much cheaper price

(Wong 2015). Despite variability in production costs and seed yield, there is strong evidence that demand for these turfgrasses is strong. Marketing research suggests that consumers are indirectly seeking fine fescue turfgrasses and are willing to pay for them.

Consumer Attitudes Toward Low-Input Turfgrasses

Consumers have quantitatively demonstrated their preference for turfgrasses that possess low-input attributes like those present in the fine fescue turfgrass taxa. Hugie et al. (2012) conducted a large-scale survey where Minnesota consumer attitudes toward a variety of common turfgrass attributes were assessed. Participants, most of which were homeowners with a lawn, were presented with different pairs of live turfgrass samples and descriptions of maintenance requirements for each e.g. high weed infestation, low mowing requirement, high fertility requirement. From the two samples presented, participants were asked to choose one based on their preferences. From these surveys, two marketing and consumer research reports were published which explored these consumer choice data in depth. The authors determined that out of a variety attributes, irrigation, price, mowing frequency, and fertility requirements were the top attributes that consumers were the most influenced by when making decisions for turfgrass use. As part of this work, the authors also created four consumer market categories from the participants, price conscious, shade conscious, mowing conscious, and water conscious to try to understand more about the specifics of turfgrass consumer behavior. Collectively

the irrigation requirement of a turfgrass in a home lawn was determined to be the most important trait according to the survey participants.

Yue et al. (2012) further analyzed data from these same choice experiments to determine how much more consumers were willing to pay in dollar amounts for certain desirable attributes in turfgrass. The low irrigation and mowing requirements and the moderate irrigation and mowing requirements were all attributes that had positively and significantly influenced consumer decision making in choosing a turfgrass as compared to the higher levels of these same requirements e.g. high irrigation or frequent mowing.

Yue et al. (2012) reported $9.70, $3.92, $5.85, $3.97 premiums for how much a consumer was willing to pay to seed an area of 92.9 m2 when these particular attributes were present in a turfgrass, respectively. For example, a consumer would be willing to pay $9.70 more for a turfgrass with the low irrigation requirement per 92.9 m2 as compared to a turfgrass with the high water requirement. Furthermore, full sun adaptation, fine-leaved texture, reduced weed presence were all turfgrass characteristics that consumers were positively influenced by in their decision-making (Yue et al. 2012).

Besides being willing to pay a premium price for low-input turfgrasses, Hugie et al. 2012 reported that 95% of participants would like to learn more about these turfgrasses. Two conclusions can be made from this marketing research. First, consumers are describing fine fescue turfgrass taxa without knowing about their existence, second, they are willing to pay a premium price for sustainable attributes in any given turfgrass.

Seed Production Regions of the World

As highlighted by Meyer and Funk (1989) improving seed producing ability is a major breeding objective in the fine fescues, especially when understanding that they are

overshadowed in seed yield and production by more common cool-season taxa like perennial ryegrass, tall fescue and Kentucky bluegrass (Ruemmele et al. 1995 & Meyer

& Funk 1989). For example, average seed yield trends and production for two fine fescues, red fescue and Chewings fescue, for a period of 29 years demonstrate that the combined progress made by these taxa was not as great as perennial ryegrass or Kentucky bluegrass (Bonos and Huff 2013). World regions producing fine fescue turfgrass seed include Oregon in the Northwestern United States, the Peace River Region in

Northwestern Canada, and Denmark in Northern Europe. Each region has a different climate, soil, cultural practice, and commercial infrastructure that determines how fine fescue seed is produced.

Oregon in the Northwestern United States

Commercial legume and turfgrass seed production began in Oregon in the 1920’s and by the 1960’s the state led the United States in the production of a variety of seed crops, including fine fescue seed production (Middlemiss and Coppedge 1970).

Presently, Oregon turfgrass seed production includes perennial ryegrass, Kentucky bluegrass, and tall fescue and certain fine fescues. Red fescue, Chewings fescue, and hard fescue have been grown for seed in and around the Willamette Valley region of Oregon.

Annually, Oregon produces an estimated 3,150,000 to 5,440,000 kilograms of fine fescue seed, from approximately 3,200 to 3,600 hectares, yields generally high and range from

1,230 to 1,450 kg per ha-1 (Oregon Agripedia 2017).

Bonos and Huff (2013) summarized Oregon seed production and yield from 1976 to 2009; they showed that two species in particular, tall fescue and Kentucky bluegrass more than tripled in seed production while red fescue seed production only increased

from 600 to 1000 kg ha-1, highlighting the slower breeding progress made with fine fescues and seed yield.

Peace River Region in Northwestern Canada

Northwestern Canada leads the world for general fine fescue seed production with an annual average of 40,400 to 48,500 hectares of production. Seed production began in the 1930’s in the Peace River Region located in the western provinces of Alberta and

British Colombia. Seed was brought into the region and experimentally grown on two farms by an agricultural warden; it then expanded greatly a decade later during the

Second World War when military demand for turf in United States airfields increased.

During the 1940’s the export of red fescue seed ranged from 13,500 kilograms to

2,220,000 kilograms (Wong 2019). This increase in seed production continued well into the 1950’s as demand from the United States exceeded production. Presently and historically, the uncertified red fescue seed from Canada, which is around 80% of the total seed produced, is exported to the United States while certified ‘Boreal’ variety seed is exported to Europe (Wong 2019, Monteith 1941). Therefore, the inexpensively produced red fescue from Canada competes with domestic seed production from Oregon.

Recall that Oregon red fescue turf seed production averaged about 3,200-3,600 hectares, substantially fewer hectares than Canadian output.

Average seed yields of fine fescue range between 500 and 550 kg ha-1, with growers applying approximately 53 kg ha-1 of nitrogen in the form of either ammonium nitrate or urea in the spring (Yoder 2000). Top yields in this region see about 800 to 900 kg ha-1 but these are usually from first production year fields and are short lived as

reduced yields are expected in latter harvest years. Canadian seed yields are on average half of Oregon average seed yields.

Denmark

The total production of red fescue in Denmark is an average of 20,200 to 24,200 harvested hectares. Average seed yields are in the 1,000 kg range per ha-1. A ten-year average from 1994 to 2003 had an average of 1,011 hectares of sheep fescue seed being produced as well. Historical subsidies from the European Union have allowed excess seed to be sold inexpensively to the United States, undercutting Canadian red fescue imports. Red fescue from Denmark is always certified and therefore has a slightly higher price than non-certified (Wong 2015).

Northern Minnesota

Minnesota’s grass seed production is located primarily in Roseau and Lake of the

Woods counties in the northern region near the border with Canadian. Grass seed production began in the 1950’s when growers in this region began to produce seed of

‘Park’ Kentucky bluegrass, a University of Minnesota variety developed by H.L Thomas

(Nancy J. Ehlke, personal communication). Presently, seed production consists mainly of perennial ryegrass and Kentucky bluegrass with no fine fescues currently in seed production. The region proved to be suitable for grass seed production as University of

Minnesota plant breeders, agronomists, soil scientists, plant pathologists, and growers have collaborated frequently over the years. Higher yielding and herbicide resistant varieties of perennial ryegrass were developed and supplied to growers; this led to it presently being the most produced grass seed crop with approximately 6,000 to 14,000 hectares of perennial ryegrass production. In comparison, Oregon produces between

36,000 and 44,000 hectares of perennial ryegrass (Bonos and Huff 2013, Oregon

Agripedia, 2012, 2017).

Red fescue seed production, or seed production of any fine fescues, is absent in this region. However, interest in growing fine fescues in this region was present in the

1970’s as shown by varietal trials published as progress reports by the Minnesota Turf

Seed Council. From these field trials, it became evident that while these turfgrasses initially drew attention from agronomists and growers, at that time they were not fully developed for successful commercial seed production in the growing conditions of northern Minnesota (Elling 1977, 1978, 1981).

Post-Harvest Residue Management Trials from Oregon and Canada

Agronomists have experimented with fine fescue turfgrasses in seed production settings with the intent to optimize seed yield and seed value. Economically viable production of these turfgrasses depends heavily on post-harvest residue management which has been investigated extensively. Nitrogen fertilizer rate and timing on fine fescues has been experimented with but conclusions on their importance to fine fescue seed production have been mixed. Lastly, herbicide applications remain important because they ensure seed purity and therefore economic value. Though all three factors are relatively important, fine fescue field experiments have historically been conducted on residue management. Residue management is important in fine fescue turfgrass seed production because research has shown that it helps maintain adequate seed yield as the seed production stand ages. Reduced yields in older seed production stands has been observed before, but it has not been well-investigated. It is thought that increase

production on vegetative tillers in subsequent years may be a factor that reduces seed yield.

Multiple fine fescue research studies have been performed in Oregon with the objective of understanding how seed yield and seed yield components are affected under different post-harvest residue removal strategies and nitrogen fertility regimens. These two seed production variables have been examined closely in fine fescue seed production field experiments. Residue management for red fescue in this region involves open-field burning, a contentious practice with historical significance in the valley for the production turfgrass seed. Open-field burning was recommended in the late 1940’s after it was discovered that it reduced disease incidence in perennial ryegrass seed production

(Oggel 1950, Oregon Department of Agriculture 2018).

After concerns arose about open-field burning, like poor air quality and contributions to soil erosion, Pumphrey (1965) tested Kentucky bluegrass and red fescue yields under thermal and non-thermal residue removal management strategies and observed that burning was not any more effective at increasing seed yield in creeping red fescue than complete mechanical removal of the residue. Yields at this time ranged between 392 and 840 kg per ha-1 with applications of approximately 112 kg per ha-1 of nitrogen per acre.

However, further research concluded that burning of the residue maintained higher yields in creeping red fescue as the stand aged (Chilcote et al. 1980).

Subsequently, Meints et al. (2001) evaluated fine fescue physiology under mechanical and thermal removal and corroborated Pumphrey (1965) by reporting that fertile tiller number, a seed yield component highly correlated to seed yield, was affected positively

only by burning in the rhizomatous strong creeping red fescue cultivars ‘Shademaster’ and ‘Hector’. When residue was removed down to ground level in these cultivars, either by thermal or mechanical means, fertile tillers increased significantly, especially so when compared to higher mechanical removal heights (Meints et al. 2001). Additionally, the non-rhizomatous slender creeping red fescue ‘Seabreeze’ had tiller numbers that were not affected by residue mechanical clipping or burning (Meints et al. 2001).

Young III et al. (1998) reported that open-field burning of residue in strong creeping red fescue cultivar ‘Cindy Lou’ was required to maintain adequate yields of between 800 to 1000 kg ha-1 over a period of four harvest seasons. However, mechanical removal of the residue was sufficient for maintaining Chewings fescue seed yields.

Chastain et al. (2011) and Zapiola et al. (2014) both corroborated Young et al. (1998) by reporting improvements in yield only in strong creeping red fescue cultivars in the 2nd and 3rd years after establishment and when thermal removal of the residue was used.

Currently field-burning is strictly regulated in the Willamette Valley, no more than 6,000 hectares of creeping red or Chewings fescue may be burned per year (Oregon Department of Agriculture 2018, State of Oregon, 2010).

Published residue management research involving creeping red fescue in Canada is limited despite leading the world in seed production. Pringle et al. (1969) investigated how fall cattle grazing affected seed yield in the following harvest season in creeping red fescue and found that it had little effect. Notably however, average seed yields for this time of 150-200 kg ha-1 were observed. Fairey and Lefkovitch (2000) evaluated five post- harvest management strategies which included propane burning and clipping on red fescue, tall fescue, and Kentucky bluegrass. They found that seed yields for red fescue

were largely uninfluenced by the different treatments. Interestingly, the power harrow treatment significantly increased the seed produced on individual panicles of red fescue but failed to increase overall grass seed yields as the panicle density was sparse. Seed yields in this time were averaged 550 kg ha-1. As reported in many other fine fescue seed production publications, first-year yields were around 1,200 kg ha-1, and in the same stand the next year, they significantly reduced to 250 kg ha-1. This might have been attributed however to extra rain during the first two years of the research trial (Fairey and

Lefkovitch 2000).

Nitrogen Fertilizer Application Rates and Timing

The rate and timing of nitrogen fertilizer in fine fescue seed production is a topic not as thoroughly investigated as residue management. Mature seed in fine fescue turfgrasses is the result of two stages, primary induction and floral initiation. Fine fescue is planted in the summer months and experience vegetative growth until cooler temperatures induce vernalization, or primary induction. In the following spring as temperatures increase floral initiation occurs in the reproductive tillers which eventually emerge after elongation from the base of the tiller. The inflorescence after emerging then produces ovules and anthers with pollen that are wind dispersed. After fertilization, the seed develops and matures. This process is dependent on day length, temperature, and nutrient availability. Furthermore, achieving commercial seed yields is a factor of the abundance of reproductive tillers, moisture, temperature, and nutrient availability (Yoder

2000).

In Oregon, Pumphrey (1965) applied incrementally increasing rates of nitrogen fertilizer, in the form of the ammonium nitrate, to established red fescue seed production

stands on growers’ fields. These fertilizer applications were made in either the fall or spring. After 100 kg ha-1 of nitrogen fertilizer the seed yields, which at this time ranged between 336 to 448 kg ha-1, stopped increasing. Furthermore, no dramatic differences were observed between seed yield at different timings of the applied nitrogen fertilizer. In this field experiment, residue management, unlike Pumphrey’s (1965) residue management field experiment, was not reported and left to the discretion of the participating grower.

In Oregon, a four-year creeping red fescue trial was planted in 1998 on two sites,

Sherman and Taylor farms, for a nitrogen field experiment investigating how spring applied nitrogen affects seed yield (Young et al. 1999, 2000, 2001, 2002). Spring nitrogen treatments included 33.6, 56, 78.4,100.8, or 123.3 kg ha-1 of total nitrogen.

Residue management and fall fertilizer applications were left to the discretion of the participating growers. From this extensive field experiment, it was determined that spring nitrogen applications above 78.4 kg ha-1 did not increase seed yields, which ranged between 1450 and 1790 kg ha-1 for Sherman and Taylor Farms, respectively (Young et al.

2002). Furthermore, it was suggested that fall nitrogen applications and split nitrogen applications may not meaningfully influence seed yield in red fescue production

(Gingrich et al. 2003).

Fairey and Lefkovitch (2000) investigated the timing and form of nitrogen applications on red fescue production in the Peace River Region in an effort to uncover how spatial applications of nitrogen and different forms of nitrogen affect seed yield.

Nitrogen at a rate of 68 kg ha-1 was applied in three forms, surface broadcast, granular form, and a combination of a foliar and soil injection with a solution for three application

times that included fall, early spring, and late spring. No combination of nitrogen application time or chemical form had any significant effects on creeping red fescue seed yield which ranged around 550 kg ha-1 (Fairey and Lefkovitch 2000).

Multiple varietal trails conduced in northern Minnesota have explored the possibility of fine fescue turfgrass seed production. A fine fescue trial was established in

1978 and included over a dozen entries. Chewings fescue varieties, ‘Cascade’ and

‘Jamestown’ yielded 204 and 244 kg ha-1, respectively. In their second harvest year, both varieties dropped in total seed yield, with each yielding as low as 3 and 51 kg ha-1, respectively. Creeping red fescue ‘Durlawn’ and ‘Pennlawn’ produced 470 and 403 kg ha-1 in their first years. In their second year, they both dropped to 193 and 98 kg ha-1, respectively. Hard fescue entries ‘6673’ and ‘66218’ produced 477 and 428 kg ha-1 in their first year and dropped their yields in the second year to 90 and 89 kg ha-1 (Elling

1981). A separately seeded varietal trial established in 1978 included yields for sheep fescue accessions. Varieties ‘66432’ and ‘67135’ yielded 128 and 253 kg ha-1 in their first years, their second year yields actually rose to 356 and 422 kg ha-1, respectively

(Elling 1978). Fertility applications for these trails were not reported, however it was clear that yields were too low for seed to be produced commercially.

Wyse et al. (1986) reported creeping red fescue yields dropping from a range of

400 to 500 kg ha-1 to 220 kg ha-1 when 80 kg ha-1 of nitrogen was applied to experimental herbicide plots in the fall once after establishment and again after the first harvest.

Decreasing yield productivity of fine fescue seed production has been documented in the past and is thought to be a result of over production of vegetative tillers. These yields

provided a glimpse into potentially producing fine fescue turfgrass seed. Ultimately, yields proved not to be high enough for growers to begin commercial production.

Herbicide Use for Seed Purity

A peculiarity among fine fescue turfgrasses is their resistance to herbicides used to control grassy weeds (Wyse et al. 1986, Stoltenburg et al. 1989). Herbicide applications are helpful in fine fescue seed production for effectively reducing or eliminating noxious weed seeds that would otherwise compromise seed purity. Growers producing fine fescue turfgrasses have a variety of available proven herbicide chemistries to choose from. Moreover, precise weed control strategies will vary among and within regions and producers based on preferred cultural management practice. Still, the major seed producing regions of Oregon and Canada share similarities in the herbicides used.

In Oregon and Canada, herbicides approved for use on fine fescue seed production include diuron (N’-(3,4-dichlophenyl)-N, N-dimethyl urea), bromoxynil (3,5- dibomo-4-hydroxybenzonitrile), dicamba (3,6-dichloro-2-methoxybenzoic acid 2,4- amine (2,4-D amine), and clopyralid (3,6-dichloro-2-pyridinecarboxylic acid) (Fairey and

Lefkotvicvh 2000, Zapiola et al. 2014, Young et al. 1998, Chastain et al. 2011, Chastain et al. 2014).

Diuron is a urea herbicide belonging to group 7. It is a photosystem II inhibitor that is approved for broadleaf and grass weeds, however, its application is only recommended on well-developed seed production stands. Bromoxynil is a nitrile herbicide in group 6, and like diuron it is also a photosystem II inhibitor. It can be used to control broadleaf weeds. Dicamba is a benzoic acid herbicide that is recommended only when seed production stands are mature. 2,4–D amine is a phenoxy herbicide that is used

to control broadleaf grasses in well-established stands. Clopyralid is a pyridine herbicide that is used for broadleaf weeds. Dicamba, 2,4–D amine, clopyralid, are all group 4 synthetic auxin herbicides (Hukting 2019, Weed Science Society of America).

These herbicides are often combined when applied for improved control of weeds like annual ryegrass (Festuca perennis), quackgrass (Elymus repens), rattail fescue

(Vulpia myuros), Canada thistle (Cirsium arvense), wild oat (Avena fatua), dandelion

(Taraxacum officinale), and foxtail barely (Hordeum jubatum). Physical removal of these contaminant seeds in costly and not always feasible for commercial seed production and in some instances it will reduce commercial value of the seed. In Minnesota agricultural commodities, like fine fescue turfgrass cannot be sold if there are certain prohibited weeds, like Canada thistle, present. Additionally, if certain restricted weeds are present in excess of 1%, like quackgrass, the seed cannot be sold to market. For this reason, herbicide applications remain an important part of fine fescue seed purity (Yoder 2000,

Alderman et al. 2011, Donn Vellekson, personal communication, State of Minnesota,

2015).

In Northern Minnesota, though no fine fescue seed production was present at the time, investigations of effective herbicides that could be used to ensure potential seed purity control took place. Quackgrass was especially problematic for any potential fine fescue turfgrass seed production since the weed seed size made it difficult to separate from red fescue seed commercially. However, in 1977 in herbicide field experiments suggested that red fescue possessed tolerance to sethoxydim, which is a cyclohexanone herbicide traditionally used to remove grass weeds (Elling 1977). Consequently, Wyse et al. (1986) investigated the tolerance of red fescue and other turfgrasses, like perennial

ryegrass and Kentucky bluegrass, by applying sethoxydim herbicide to accessions in greenhouse trials and field experiments. Tolerance was evaluated visually with plant injury ratings on a 1-99 scale. In the greenhouse experiments, red fescue demonstrated complete tolerance to sethoxydim, this is in contrast to the other cool-season turfgrasses which showed extensive herbicide damage. In field experiments sethoxydim had no effect on seed yield when applied at increasing rates of 0.6 to 1.7 kg ha-1. Additionally, the control of quackgrass weed seed was excellent. The resistance to sethoxydim herbicide was later attributed to an acetyl carboxylase enzyme whose activity was not inhibited by up 1000 M of sethoxydim, which is comparable to pea, an agronomic dicot crop. This enzyme peculiarity among fine fescue turfgrasses is not shared by other taxa of the Festuca genus, like tall fescue. At the time, this drew much attention for fine fescue seed production at the time. However, red fescue yields proved too low and unstable for profitable commercial seed production to be considered (Wyse et al. 1986, Stoltenburg et al. 1989, Burton et al. 1987).

Summary and Hypotheses

Fine fescue turfgrass taxa are excellent consumer-desired low-input turfgrasses that function and persist in temperate climates. Turfgrass breeders continue to improve germplasm through the use of wild accessions from North America and Europe. They have performed well in field trials by demonstrating vigor under moderate to extreme environments and in golf greens and home lawns. Seed production of these turfgrasses, centered in Canada, Denmark, and Oregon USA, is limited and has caused difficulty for consumers to obtain these sustainable turfgrasses. Marketing research has provided

evidence that consumers value the minimal maintenance attributes found in the fine fescues and are willing to pay a premium for them.

Given the limited seed production of fine fescue taxa and the general concern for sustainability, efforts to begin producing seed of these specialized turfgrasses in northern

Minnesota are justified. Successfully introducing seed production in this region will require knowledge of how well these taxa perform in a seed production setting.

Specifically, data on the general performance of multiple fine fescues under common nitrogen fertilizer management systems is not reported in the literature recently in

Minnesota. As noted, most of the fine fescue seed production experiments report results from residue management studies, experiments on nitrogen fertilizer rate and timing experiments are lacking in the literature. Ensuring seed purity by testing various proven herbicides on fine fescue taxa in herbicide safety experiments are also missing from the literature.

As part of an effort to aid northern Minnesota seed producers begin producing fine fescue turfgrasses seed, field experiments were conducted on nitrogen fertility requirements and herbicide safety. This project has two primary objectives: (1) understand how fine fescue taxa yields are affected under different nitrogen management practices, and (2) understand how hard fescue is affected by various proven herbicide applications.

Chapter 2: Seed Yield and Components of Five Fine Fescue Taxa Under Different

Nitrogen Fertility Practices

Introduction

Fine fescue turfgrasses are a group of naturalized taxa in the Festuca genus that collectively possess low-maintenance traits likes slow growth, drought tolerance, reduced fertility requirements, and winter hardiness (Beard 2013, Bonos and Huff 2013). They have consistently demonstrated the ability to perform adequately and maintain acceptable turfgrass quality under minimal conditions like drought and reduced soil fertility (Bertin et al. 2009, Watkins et al. 2010, 2014). Additionally, they are capable of persisting in acid, saline and lead contaminated soils, and have demonstrated the ability to reduce weed incidence (Bertin et al. 2009, Brown and Brinkman 1992, Zhang 2013). Marketing research provides evidence that consumers desire the low-input characteristics found in fine fescue turfgrasses (Hugie et al. 2012, Yue et al. 2012). In spite of that, high seed costs, obscurity to the general public, and limited seed production are preventing these more sustainable turfgrasses from being used as widely in sports fields, green spaces, and home lawns as their conventional counterparts.

The Peace River Region in Canada, Denmark, and Oregon, USA are the three major seed producing regions of fine fescue turfgrass seed (Wong 2015, Oregon

Agripedia, 2012, 2017). Profitable seed production stands in these regions are perennial and may last three to four growing seasons, and typically the seed yields decline after the first year of production (Yoder 2000). Fine fescue seed yields in Oregon and Denmark average 1,000 kg ha-1, these observed yields are twice as great as Canadian fine fescue seed yields. However, acreage of fine fescue turfgrass seed in Canada is the largest,

around 40,400 hectares which greatly exceeds any domestic or European seed production. Oregon’s fine fescue seed production consists of mainly red fescue (Festuca rubra L. spp.) and Chewings fescue (Festuca rubra L. spp. communata), with some limited production of hard fescue (Festuca brevipila T.). In contrast, Canada mainly produces red fescue ‘Boreal’. Fine fescue seed with origins from Oregon is typically more expensive to produce due to higher lands costs, especially so when compared to the inexpensively produced Canadian fine fescue seed. However, most of the seed produced in Canada is exported to the US and is subject to tariffs (Wong 2015, 2019).

Northern Minnesota’s turfgrass seed production region is concentrated in Roseau and Lake of the Woods counties and produces mostly perennial ryegrass (Lolium perenne

L.) and limited Kentucky bluegrass (Poa pratensis L.) seed. Fine fescue turfgrass seed production has been considered for this region, however, poor seed yields and weed infestations have prevented production to date. In historical publications, inconsistencies in seed yields from the first harvest year to the second and commercially low seed yields were common issues (Elling 1977, 1978, 1981, Wyse et al. 1986).

Fortunately, improvements in seed yield of fine fescues grown in Oregon have been observed over the years and provide some promise of introducing commercially viable seed production to elsewhere (Bonos and Huff 2013). Inexpensively producing fine fescue turfgrass seed in Minnesota would benefit growers and ultimately increase use and awareness of these sustainable turfgrasses. Success in this relies heavily on resourceful nitrogen fertility management strategies for optimum seed yield. In past experiments, nitrogen fertility has been studied in fine fescue taxa primarily in the region of Oregon.

Pumphrey (1965) applied increasing levels of nitrogen fertilizer on red fescue over multiple growing seasons and was observed that nitrogen applications above 100 kg ha-1 resulted in no further increases in fine fescue seed yields, which at the time ranged between 336 and 448 kg ha-1. Similarly, Young et al. (2002) applied increasing levels of nitrogen fertilizer up to 123 kg ha-1 to two red fescue seed production stands on different grower sites in a four-year field experiment. Only at one site did Young et al. (2002) conclude that 78 kg-1 was the optimum nitrogen fertilizer level to achieve seed yields in the 1450 and 1790 kg ha-1 range. The other site had a similar seed yield range regardless of fertilizer treatment application. In Canada, Fairey and Lefkovitch (2000) applied nitrogen fertilizer in multiple forms and at different timings at the same rate of 68 kg ha-1 to red fescue and found that average seed yields remained approximately 550 kg ha-1 regardless of nitrogen form used and timing of application.

Nitrogen fertility management practices for fine fescue seed production is an important aspect that has not been well-studied on improved germplasm in Minnesota.

Therefore, the two objectives of this study were to subject five fine fescue taxa and cultivars in three environments over two growing seasons to different nitrogen management strategies in an effort to a) reveal if any fine fescue taxa are affected by different nitrogen management strategies in terms of yield and seed yield components; and b) determine which fine fescue taxa show promise for commercial seed production in

Minnesota.

Materials and Methods

Experimental seed production plots were established by direct seeding in three locations in Minnesota: Minnesota Agricultural Experiment Station in St. Paul seeded on

2 Sept. 2016, Sand Plain Research Site in Becker seeded on 7 July 2016, and Magnusson

Research Farm in Roseau seeded on 7 July 2016 on Waukegan silt loam, Hubbard-

Mosford loamy sand, and Borup silt loam, respectively. The experimental design was a randomized complete block design with three replications and a factorial set of treatments consisting of a combination of five nitrogen fertility management practices and five fine fescue taxa.

The fine fescues used in the experiment were: hard fescue (Festuca brevipila T.)

‘MNHD’, sheep fescue (Festuca ovina L.) ‘Quatro’, Chewings fescue (Festuca rubra L. ssp. commutata) ‘Windward’, strong creeping red fescue (Festuca rubra L. ssp. rubra)

‘Cindy Lou’, and slender creeping red fescue (Festuca rubra L. ssp. litoralis) ‘Shoreline’

(Table 1). ‘MNHD’ is an improved population developed by the University of Minnesota while the rest of the cultivars were developed by private seed companies and are sold commercially in the United States. There were five nitrogen management treatments applied at specific dates in the fall and spring: (0) no nitrogen, (1) a split application of

22.42 kg ha-1 applied in the spring and fall (split low), (2) 44.8 kg ha-1 applied all at once in the fall (low), (3) a split application of 44.8 kg ha-1 applied in the fall and spring (split high), and (4) 89.6 kg ha-1 applied all once in the fall (high) (Table 2). Nitrogen fertilizer, broadcast in the form of granular urea (46-0-0) is standard practice for turfgrass seed growers in Minnesota. Rainfall events after nitrogen application are listed in Table 3.

The 1.8 x 6.1 m experimental seed production plots were seeded at a rate of 5.6 kg ha-1 in rows that were spaced 15.2 cm apart. Plots were seeded using a Hans-Ulrich

Hege double-disk furrow opener 10 row plot seeder. Prior to direct seeding each experimental site had specific preparations. The St. Paul site had an application of starter

fertilizer (0-46-0) at a rate of 123 kg ha-1 on 29 Aug. 2016. The Becker site was previously seeded with rye (Secale cereale L.) which had a spring granular urea (46-0-0) fertilizer application at a rate of 93 kg ha-1. The Becker site was also irrigated twice per week during the growing season at a depth of 0.76 cm due to sandy soil. Roseau had starter fertilizer applications of consisting of (11-52-0), (46-0-0), and (0-0-60) at the rates of 86 kg ha-1, 263 kg ha-1, 75kg ha-1, respectively applied on 17 May 2016 before seeding occurred.

Weed control measures consisted of herbicide applications applied with a pressurized bicycle sprayer at the time of establishment and thereafter. In Roseau fluozifop-p-butyl (butyl-(R)-2-(4-{[5-(trifluormethyl)-2-pyridyl]oxy}phenoxy) propionate) was applied at a rate of 448 g a.i. ha-1 with 1% crop oil concentrate surfactant on 28 Aug. 2017. Pendimethalin (3,4-Dimethyl-2,6-dinitro-N-pentan-3-yl-aniline) was applied at a rate of 2129 g a.i. ha-1 on 30 July 30 2017.

In Becker clopyralid (3,6-Dichloropyridine-2-carboxylic acid), 2,4–D amine (2,4-

Dichlorophenoxy) acetic acid), dicamba (3,6-dichloro-o-anisic acid), and fluazifop were applied at the rates of 106, 560, 59, and 448 g a.i. ha-1, respectively on 1 Sept. 2016.

Dicamba was applied at a rate of 420 g a.i. ha-1 on 24 Apr. April 24 2016. Subsequently, pendimethalin was applied at a rate of 1597 g a.i. ha-1 on 30 July 2017. Then, a combined application of quinclorac (4-Chloro-2-methylphenoxy)acetic acid), clopyralid, and

MCPA (4-Chloro-2-methylphenoxy)acetic acid) at the rates of 420, 117, and 658 g a.i. ha-1 were made on 29 Aug. 2017.

In St. Paul clopyralid, MCPA, and fluazifop were applied at the rates of 117, 658, and 448 g a.i. ha-1 of on 26 Aug. 2016. Carfentrazone (ethyl 2-chloro-3-[2-chloro-5-[4-

(difluoromethyl)-3-methyl-5-oxo-1,2,4-triazol-1-yl]-4-fluorophenyl] propanoate), 2,4–D amine, and dicamba were applied at rates of 26, 532, and 420 g a.i. ha-1, respectively on

28 Sept. 2016. After the first harvest, pendimethalin at a rate of 3194 g a.i. ha-1 was applied on 28 July 2017.

At the three locations, plots were harvested between late June and early July in the as seed matured. In 2017, the first harvest year, a metal frame 1 m2 quadrat was placed randomly in a plot so long as 5 rows fit within the frame, all mature panicles within the quadrat were harvested. In 2018, two 1 m2 quadrats were harvested from each plot to estimate seed yield. Shortly after harvest, the residue was mowed and removed from all plots.

After harvest the yield samples were placed in cloth bags and then were dried in a

32 oC oven for 36 to 48 hours. After drying, total sample weight was taken and samples were mechanically threshed using either a large continuous seed thresher from Mater

Seed Equipment OEM, Inc. Corvallis, OR for large samples, or a ALMACO belt-thresher by Allan Machine Works Ames, IA for smaller ones. Once all samples had been threshed the seed was cleaned by passing it through a Carter-Day Inc. aspirator and then by manually sifting it through two differently sized aluminum seed cleaning sieves

SeedBuro, the first an 8-1/2 mm and the second a 6-5/8 mm in diameter. Seed samples and plant biomass samples were weighed before and after to determine a harvest index and seed yield.

In 2018, seed yield component data was taken from five randomly sampled panicles, a minimum of 30 cm in length, from each plot as the panicles were maturing from different plants. The five panicles were then weighed and an average was obtained

for each plot. Spikelets panicle-1 was taken by counting every spikelet from each of the five panicles sampled and averaged to obtain spikelet per panicle for each plot. Florets spikelet-1 was taken by counting florets from five different florets belonging to one of the five sampled panicles per plot, this value was averaged. Panicles m-2 was taken by counting panicles from two randomly selected 0.046 m2 quadrats from each plot.

Thousand seed weight was determined by 1000 counting seeds from yield samples using a Diamond Counter D-JR from Data Technologies and then weighing the seeds samples from each plot.

Two growing seasons of data with three locations resulted in six experimental environments for the data analysis because of heterogeneity of the data across locations and years, and because of the aforementioned differences in pre-establishment site preparations. The analyses of variance and mean separation procedures were performed using the packages “agricolae” and “lsmeans” in R statistical programming environment

(version 3.6.0) (Lenth 2018, de Mendiburu 2019, R Core Team 2015). Function aov was used to build each model with each year and location comprising one experimental environment. Yield, harvest index, thousand seed weight, panicle weight, spikelet florets-

1, florets spikelet-1, and panicles m-2 were included as response variables. Fine fescue taxa

(A) and nitrogen fertility treatment (B) comprised the two main effects, while there was an interaction of taxa and nitrogen treatment included in all six analyses of variances part of the model. The function lsmeans was used to perform the mean separation procedure for any experimental environment with significant interaction between taxa and nitrogen fertility treatment.

Weather data was accessed through the North Dakota Agricultural Network

(NDAWN) and the Minnesota Department of Natural Resources. Mean precipitation, high temperatures, and low temperatures were accessed for 2017 and 2018 for the months of March through July. Precipitation means were also recorded for the fall of 2016 and

2017 for the months of August through October. Soil tests for residual nitrates were taken post-harvest in 2017, and 2018 by using a tubular soil sampler and sampling from two depths of 1 to 15 cm and 15 to 30 centimeters from every hard fescue ‘MNHD’ plot across all nitrogen treatments and replications in every location. In all, two soil cores were taken from 15 plots in each locations and composited. Soil tests were sent to the

Soil Testing Laboratory, St. Paul MN and analyzed for nitrate levels. Differences in soil nitrate levels between 2017 and 2018 growing seasons were analyzed in R (version 3.6.0) for differences in each location using function t.test. Additionally, differences for residual nitrate levels for different N fertilizer treatments was assessed using an analysis of variance using function aov (R Core Team 2015).

Results

Rainfall, Temperature, and Residual Soil Nitrate

Through the months of March and July, St. Paul in 2017 and 2018 growing seasons had 41.6 and 40.5 cm, respectively, of average rainfall, making it the location with the highest levels of precipitation. Roseau had only 16.9 and 14.4 cm. (Table 4). For these same months, the maximum average temperatures were recorded in the 16 to 18oC range for max and 2 to 3oC for minimum temperatures for all three locations. St. Paul and

Becker received more average rainfall in the months of August through October in 2016

and 2017 than Roseau; 46.8 and 38.0 cm for 2017 and 2018, and 36.2 and 31.8 cm in

2016 and 2017, respectively. Roseau only received 20.9 and 19.9 for 2016 and 2017.

Statistical analyses revealed that residual soil nitrate levels from within a depth of

30 cm rose significantly in 2018 from 2017 for all three sites (Table 4). In Roseau, soil nitrate went up to 1.78 from 1.25 mg kg-1 soil from 2017 to 2018. In Becker, soil nitrate went up to 1.52 in 2018 from .47 mg kg-1 soil in 2017. In St. Paul soil nitrate went up to

3.75 in 2018 from 1.62 mg kg-1 in 2017. The analysis of variance revealed no differences for residual nitrate levels across different N treatments.

Harvest Index, Seed Weight, and Seed Yield Components

Only in two experimental environments, Becker 2017 and Roseau 2018, was the harvest index influenced by nitrogen treatment (Table 5) In Roseau 2018, hard fescue had a harvest index of 0.39 with no application of nitrogen, which proved to be higher than the harvest indices with the rest of the treatments. In sheep fescue, a harvest index of 0.35 under the split low treatment was greater than the harvest index of 0.21 under the low nitrogen treatment (Table 11). In Becker 2017, Chewings fescue under the split high nitrogen treatment had a harvest index of .10, which was significantly lower than all other harvest indices for the other N treatments. In slender creeping red fescue, the harvest index of 0.04 under split high nitrogen treatment was significantly less than the harvest index of treatments control, low nitrogen, and high nitrogen (Table 7). In no experimental environment were there any significant treatment and taxa interactions for thousand seed weight, panicle weight, spikelet panicle-1, florets spikelet-1 and panicles m-2.

Yield

St. Paul 2017, Roseau 2017, and Roseau 2018 had significant taxa and nitrogen treatment interactions with respect to the yield response (Table 5). In St. Paul 2017

(Figure 1 and Table 6) hard fescue yield was significantly influenced by nitrogen treatments split high and high which yielded 803 kg ha-1and 790 kg ha-1 respectively, when compared to the yield mean of the control, 536 kg ha-1. The split high and high nitrogen treatments had yields that were not different than split low and low nitrogen treatments.

In Roseau 2017 (Figure 5 and Table 8), hard fescue, sheep fescue, and slender creeping red fescue had significant nitrogen treatment and taxa interactions. Hard fescue under the high nitrogen treatment had a yield of 1930 kg ha-1 which was significantly greater than yield with no nitrogen applied, 1493 kg ha-1, but was not different than the rest of the nitrogen treatments means; the same trend was found for sheep fescue, with the high nitrogen treatment yielding 1257 kg ha-1. The high nitrogen treatment mean was not any different than the other nitrogen application means. For slender creeping red fescue, the split low nitrogen treatment resulted in a yield, 1347 kg ha-1, that was greater than the mean for split high nitrogen treatment, which was 860 kg ha-1.

In Roseau 2018 (Figure 6 and Table 11), hard fescue and Chewings fescue had significant nitrogen treatment by taxa interactions for seed yield. Hard fescue had a mean of 375 kg ha-1 under the control nitrogen treatment that was significantly higher than all the other nitrogen treatment applications. For Chewings fescues the yield for the split high nitrogen treatment, 376 kg ha-1, yielded more than control nitrogen, split low, and low.

Comparing Experimental Environments Broadly

Looking at the six experimental environments broadly, Roseau 2017 had the highest yields across the fine fescue taxa. Across all treatments the seed yield ranges were hard fescue 1493 to 1930 kg ha-1, sheep fescue 793 to 1256 kg ha-1, Chewings fescue 1730 to 2163 kg ha-1, strong creeping red fescue 1786 to 1933 kg ha-1, and slender creeping red fescue 860 to 1346 kg ha-1.

However, in Roseau 2018, across all treatments, yield reductions were as follows: hard fescue yield dropped to a range of 160 to 375 kg ha-1, sheep fescue to 98 to 191 kg ha-1, Chewings fescue 136 to 376 kg ha-1, strong creeping red fescue 46 to 96 kg ha-1, and slender creeping red fescue to 18 to 31 kg ha-1.

Comparing yields from Becker 2017 and Becker 2018, there were no major differences between these two years. Most of the treatment and taxa combinations did not achieve yields above 500 kg ha-1 regardless of the taxa and nitrogen treatment.

In St. Paul 2017 and 2018 hard fescue had a yield ranges of 536 to 803 kg ha-1, and 565 to 818 kg ha-1, respectively, making it the top performing taxa across N treatments. The other taxa and treatment combinations failed to achieve favorable yields in these two experimental environments for this site.

Discussion

Rainfall, Temperature, and Residual Soil Nitrate

Apart from a 50% reduction in total rainfall in Becker 2018 from Becker 2017, there were no major temperature or precipitation fluctuations through the 2017 and 2018 growing seasons that could have significantly impacted seed yield or related response variables (Table 4). Furthermore, the Becker site was irrigated, the reduction in total rainfall should not have influenced seed yields. Of the three experimental locations,

Roseau had the lowest precipitation of 14.4 and 16.9 cm for 2017 and 2018, these lower moisture levels may have not affected yield since they are similar between growing seasons. Rainfall means assessed in the months of August through October in fall 2016 and 2017 show that St. Paul and Becker sites received more rain than Roseau. However, changes mean rainfall between years for these months were not dramatic across locations and may not have affected seed yield in the following growing season (Table 4).

The residual soil nitrate levels analyses revealed that plots that received split high and high N treatments accumulated no more residual nitrate than plots that received the low, split low, and no nitrogen treatments. Soil nitrate data analysis also revealed that in each experimental location there was an increase in the level of residual soil nitrate from

2017 to 2018. This observation was the most dramatic in St. Paul and Becker where levels more than doubled from 2017 to 2018. Residual soil nitrate levels in Roseau increased as well, however not as dramatic but still significant.

Importantly, plots receiving high N treatments did not accumulate any more residual nitrate than plots that were not fertilized at all. This increase in residual soil nitrate might be explained by the sequential N treatment applications from one growing season to the next. Since soil nitrate levels were only measured during post-harvest, it is difficult to make any firm conclusions to explain this phenomenon. Young et al. (2002) measured residual soil N averages from a three-year period from fine fescue seed production sites fertilized with increasing levels of N fertilizer. Residual nitrate was measured to a depth of 91 cm and found that virtually all nitrate concentrations were under 10 ppm, reduced ability for the nitrate to leech. Young et al. (2002) speculates that this is because residual nitrate levels are considerably low even after high nitrogen

fertilizer applications on fine fescue seed production plots and that fine fescues are efficient at absorbing excess nutrients.

Harvest Index, Seed Weight, and Seed Yield Components

Conventionally, a lower harvest index value is less desirable because it suggests that the plant has allocated resources toward vegetative biomass instead of seed. In these field experiments, there were a total of four taxa in two experimental environments that had harvest indices affected by nitrogen treatment, however there was an inconsistency in how harvest index changed relevant to the varying N treatments. For example, in Becker

2017 Chewings fescue under the split high N treatment had a meaningfully lower harvest index of .10 when compared to the rest of the N treatments, indicating more biomass as a result of the addition of nitrogen. In this same experimental environment slender creeping red fescue also had a meaningfully lower harvest index of .04 produced under the split high N treatment that was lower than the rest of the N treatments, except the split low N treatment which was .0828. Remarkably, the split high N treatment produced more biomass in the two taxa but the high N treatment, which had the same amount of N applied only in the fall, did not cause a lower harvest index.

In Roseau 2018, the hard fescue under all N treatments had lower harvest indices when compared to the harvest index under the no N treatment. In this same environment sheep fescue under the low N treatment had a lower harvest index of 0.21 which was lower to the harvest index of .35 under the split low N treatment. In summary, there was no consistent response for how harvest index is affected by varying N treatment applications, nor is there enough evidence from these data to the claim that harvest index is affected by N applications since only four taxa in two experimental environments were

significantly affected. Young et al. (1999, 2000, 2001, 2002) reported similar results when harvest index did not consistently significantly decrease despite increasing levels of

N fertilizer applications.

In no experimental environment did nitrogen treatment have a significant effect on thousand seed weight, panicle weight, spikelet panicle-1, floret spikelet-1, and panicle m2 for any of the taxa used in this experiment. How seed yield components are affected by varying levels of N amendments is complicated by evidence that productivity of fine fescue stands change as they age. Young et al. (1999-2002) reported harvest index, thousand seed weight, spikelet panicle, florets spikelet, and fertile m-2 averages over four growing season from seed productions plots in two grower sites in Oregon. Like our results, they found no evidence that increasing levels of N consistently affect seed yield components in fine fescue in any meaningful way. There is some preliminary evidence that panicles m-2, a trait that has been correlated with seed yield in past research, does positively increase as a result of increased N fertilizer applications. However, results from these experiments do not validate that observation (Chastain et al. 1997).

Yield

By and large, the data does not support the hypothesis that seed yield of fine fescue taxa are consistently affected by varying nitrogen treatments or the timing of such treatments. This has been observed in past field experiments where increasing rates of N applied to fine fescue at either spring or fall did not results in proportionally greater increases in seed yield (Gingrich et al. 2003, Yoder 2000). Pumphrey (1965) observed no further increases in fine fescue seed yield above 100 kg ha-1 of N applied in the spring.

Young et al. (2002) applied N in increasing increments to fine fescue at two field sites. It

was observed that in one of the field sites no differences were observed in seed yield from the control N treatment to the higher, over 100 kg ha-1, N applications. Moreover,

Fairey and Lefkovitch (2000) applied N at the same rate in the spring but at different forms and found no difference in seed yield. Nonetheless, St. Paul 2017, Roseau 2017, and Roseau 2018 experimental sites did have significant nitrogen treatment by taxa interactions occur, meaning that only in these experiments did nitrogen treatment influence seed yield.

Strong creeping red fescue had no differences in yield for any nitrogen treatments in any experimental environment. Sheep fescue, slender creeping red fescue, and

Chewings fescue were taxa that had at least one significant interaction in one out of six experimental environments. Notably, in these instances the higher nitrogen treatment did not always result in a higher yield. For example, in slender creeping red fescue in the

Roseau 2017, the split high N treatment had a mean yield of 860 kg ha-1. At the same time when the split low N treatment was applied mean yield increased to 1347 kg ha-1.

This type of interaction where the low nitrogen application resulted in increased seed yield occurred in no other experimental environment for this taxa in these field experiments. Notably, previous fine fescue nitrogen fertility management experiments have shown fine fescue seed yield not increasing with increasing nitrogen, furthermore supplemental fertilizer may only be creating an abundance of vegetative tillers that crowd out the production of fertile tillers (Gingrich et al. 2003, Pumphrey 1965).

However, sheep fescue in Roseau 2017 had a more conventional yield response to an increased nitrogen application rate. The high nitrogen treatment had a mean yield of

1257 kg ha-1, which was greater than the mean yield under no nitrogen application, 793

kg ha-1. This sort of positive response to increased nitrogen occurred in no other experimental environment for sheep fescue. As for Chewings fescue, in Roseau 2018, the split high application of 44.8 kg ha-1 resulted in a yield mean of 376 kg ha-1, which was greater than the rest of the nitrogen treatment applications. Again, this positive nitrogen yield response occurs in no other experimental environment for this taxa. The data in these field experiments support that sheep fescue, Chewings fescue, strong creeping red fescue, and slender creeping red fescue yielded similarly regardless of nitrogen fertility application treatments. This was consistently observed across all experimental sites despite the variation differences in site preparation and soil type.

Hard fescue had a significant yield response to the nitrogen treatments in three of the six experimental environments making it the only taxa influenced by nitrogen treatments in more than one experimental environment. In St. Paul 2017, hard fescue under the split high nitrogen treatment and the high nitrogen treatment had a yield of 803 kg ha-1 and 790 kg ha-1, respectively. These two yields were higher than the mean yield of

536.7 kg ha-1 where no nitrogen was applied. In Roseau 2017, hard fescue had a yield of

1930 kg ha-1 for the high nitrogen treatment, which was meaningfully greater than the mean of 1493 kg ha-1 under no application of nitrogen. In these last two instances the hard fescue had a positive response to nitrogen, however in Roseau 2018 under no nitrogen application a yield of 375 kg ha-1 was observed, significantly more than the rest of the nitrogen treatments.

Importantly, there are two applications where higher rates of N application increased seed yield of hard fescue, providing some evidence that higher nitrogen application rates will positively affect yield in this taxa. Also, the low and split low rates

produced mean seed yields comparable to no supplemental nitrogen applied. Other similarly conducted N fertilizer field experiments on fine fescue have also provided evidence that some taxa’s seed yields will increase statistically when N fertilizer is added.

Young et al. (2002) found that N fertilizer applications of between 33 and 78 kg ha-1 will meaningfully increase seed yield in Chewings fescue cultivar ‘Brittany’ and red fescue cultivar ‘Shademark’, however these results were reported in only one of two experimental sites. Though most past research has shown that fine fescue turfgrass seed yield may not respond to increasing nitrogen applications, certain publications recommend some N applications to be useful in maintaining desirable seed yields

(Gingrich et al. 2003).

Comparing Experimental Environments Broadly

The Becker site in both years had fairly lower seed yields, this could have been due to excessive drainage on the sandy soil, which retain nutrients like nitrate poorly

(Table 4). Low yields from the Becker site could also be explained by lower levels of residual nitrate compared to other sites. Though Becker site in the spring of the year of establishment was seeded with rye and fertilized with 93 kg ha-1, rye likely used most of that N and therefore made it unavailable to the fine fescue seeded that July. While hard fescue in St. Paul had favorable seed yields, its averages for the rest of the taxa are low.

St. Paul yields in 2018 seemed to have improved (Figure 1 and 2). This might have been due to a latter planting date of September 9th in the establishment year, the two other sites were established in June.

The most successful experimental environment was Roseau 2017, the first year of seed production. The two-year average for across all N treatments for this location were

989, 584, 1101, 956, and 564 kg ha-1, for hard fescue, sheep fescue, Chewings fescue, strong creeping red fescue, and slender creeping red fescue, respectively. During site preparation, the Roseau site received significant supplemental nitrogen fertilizer, and may help explain some of these higher yields during the first growing season. The sharp drop in yield observed in the second growing season in Roseau is a phenomenon overserved in fine fescue seed production in past research (Yoder 2000), however a late harvest in 2018 may have caused seed yield loss through seed shatter.

Conclusions and Implications

A main objective of these field experiments was to determine if fine fescue taxa are influenced by nitrogen treatment applications in Minnesota with respect to seed yield and seed yield components. In these field experiments most taxa had no significant response in seed yield or seed yield components from various nitrogen treatments applied at different times in multiple experimental environments. This provides supporting evidence that seed yield of fine fescues turfgrass taxa are not significantly influenced by supplemental nitrogen applications applied at different times. In conclusion, applications of N fertilizer may not be as important in fine fescue seed yield as other factors like residue management (Pumphrey 1965, Young et al. 2002, Fairey and Lefkovitch 2000).

Nonetheless, hard fescue ‘MNHD’ was one taxa and cultivar that demonstrated improved seed yields in first year seed production establishments from the high N treatment applications applied in the fall or split between the fall and spring.

Harvest index and panicle m2 in past field experiments have been shown to be affected by varying levels of N, however in these experiments there was no data to corroborate that response. Additionally, data from these field experiments corroborates

past experiments where thousand seed weight, spikelets panicle-1, and florets spikelet-1 were found to be unaffected by varying levels of N. This is evidence that these variables are determined mostly by taxa. (Young et al. 1999-2002, Zapiola et al. 2014).

The limited range of cultivars of fine fescue used within these field experiments may reduce the weight of firm conclusions made. Previous research has shown fine fescue cultivars form the same taxa to perform different in field experiments (Elling,

1977, 1978, 1981). Additionally, past experiments demonstrate residue management as being a strong influencer of yield, and though residue management was not investigated here, different residue management strategies may have important interactions with respect to varying N applications. Though these results provide evidence that hard fescue

‘MNHD’ seed yield may increase in response to N fertilizer applications that at or above

89.6 kg ha-1, this phenomenon was only observed during first year seed establishments.

Granular urea is the most common form of N fertilizer used by growers in northern Minnesota. However, it has drawbacks in reliability mainly caused by N loss through volatilization, leeching, and denitrification. Residual nitrate levels in post-harvest was measured to be no more than 10 ppm (Table 4), which is still considerably low for any significant N loss though leeching (Young et al. 1999, 2000, 2001, 2002). Urea volatilization to ammonia gas is another concern that could have altered the available N to the roots and therefore yield and other response variables. There were some instances where there was a significant delay in rain, up to 10 days, after a N treatment application was made. However, average temperatures (Table 3 and Table 4) were low enough to reduce significant volatilization.

There is some evidence that Roseau 2018 yields ought to have been higher for hard fescue ‘MNHD’. A late harvest and seed shatter likely caused a loss in yield observed in the data for that particular growing season. Since harvest index data was not compared statistically between years for the same experimental site it is difficult to make any firm conclusions that may provide insight for this. Moreover, while harvest index in

Roseau 2017 were not different across N treatments for hard fescue, in 2018 the harvest index control treatment had a value of 0.39, which was significantly greater than the rest of treatments. Consequently, in the same experimental environment, seed yield under the control treatment was also the highest at of 375 kg ha-1. It is difficult to explain this result on the context of the general reduction in seed yield from 2017 to 2018.

These field experiments were conducted to help determine if fine fescue could be commercially produced in Minnesota. This depends on whether growers in this region can achieve commercially viable seed yields while maintaining minimum costs of production. Presently, commercially viable seed yields in Minnesota must range between

500 and 600 kg ha-1, which is average seed yield of N fertilized fine fescue in the Peace

River Region of Canada in order to be competitive. This average has been observed in this investigation across a range of taxa. Canadian fine fescue seed production has the disadvantage of having to be exported to the United States, which is their biggest consumer. In Oregon, seed producers applying supplemental N fertilizer are reporting fine fescue seed yields in the 1000 kg ha-1 range, this is twice as high as Canada.

Furthermore, this seed is domestically produced. Ideally, Minnesota growers would greatly benefit from achieving average seed yields similar to Oregon because that would allow them to be competitive with this domestic producer.

However, northern Minnesota has land costs that are similar to the Canadian seed production region and is therefore able to maintain lower seed production costs i.e. seed yields could remain competitive at a 500 kg ha-1 average. As demonstrated in this investigation, achieving the 500 kg ha-1 seed yield average across a range of fine fescue is possible, and may or may not require the use of N; however, we need to learn more about nitrogen requirements for maintaining high levels of multi-year seed production. Average seed yields for all taxa across N treatments fall within the range of 500 to 1000 kg ha-1 especially for the Roseau site. Furthermore, hard fescue ‘MNHD’ at a high N fertilizer rate increased seed yield by around 250 to 300 kg ha-1. While these yield increases were found to be statistically significant, from an agronomic perspective they may or may not offset the economic returns to growers. These seed yield increases must be greater than the cost of applying N fertilizer.

Table 1 – Fine fescue taxa, common name, and respective cultivar used in the fertility experiments.

Taxa Common Name Cultivar Festuca brevipila T. Hard fescue ‘MNHD’ Festuca ovina L. Sheep fescue ‘Quatro’ Festuca rubra L. ssp. commutata Chewings fescue ‘Windward’

Festuca rubra L. ssp. rubra Strong creeping red fescue ‘Cindy Lou’

Festuca rubra L. ssp. litoralis Slender creeping red fescue ‘Shoreline’

Table 2 – Nitrogen treatments used in the field experiments. Treatment key for figures 1 through 6 and for tables 6 through 11.

Nitrogen Fall (kg ha-1) Spring (kg ha-1) Total (kg ha-1) Treatment

none 0 0 0 split low 22.4 22.4 44.8 low 44.8 0 44.8 split high 44.8 44.8 89.6 high 89.6 0 89.6

Table 3 – Dates of nitrogen treatment applications (Date) across the six experimental environments and the number of days elapsed (Rain) before a rain event occurs.

Fall 2016 Spring 2017 Fall 2017 Spring 2018

St. Paul Date September 29 May 8 September 24 April 30 Rain 6 (1.72 cm) 1 (.5 cm) 1 (.78cm) 2 (.58 cm) Becker Date September 1 May 11 September 28 April 29 Rain 5 (4.0 cm) 5 (1.7 cm) 4 (2.2 cm) 3 (.12 cm) Roseau Date September 20 May 10 October 16 April 29 Rain 4 (2.1 cm) 9 (.25 cm) 7 (.25 cm) 2 (.33 cm) Minnesota Department of Natural Resources, North Dakota Agricultural Weather Network

Table 4 – Soil nitrate content, precipitation, and maximum and minimum mean temperature data across the six experimental environments. Precipitation and temperature are measured March through July.

Location Residual precipitation Max mean Min mean nitrate (mg/kg (cm)** temperature temperature soil)* (oC) (oC) Roseau 2017 1.25b 16.9 16.2 3.2 (20.9) 2018 1.78a 14.4 16.3 2.7 (19.9) Becker 2017 .47b irrigated 18.1 6.0 (36.2) 2018 1.52a irrigated 17.9 5.6 (31.8) St. Paul 2017 1.62b 41.6 18.2 7.5 (46.8) 2018 3.75a 40.5 13.6 7.8 (38.0) *residual soil nitrate content was analyzed for differences between years the p=.05 level for each site, ** value in parenthesis indicates mean rainfall August through October of the previous fall

Table 5 - Analysis of variance for yield, harvest index, thousand seed weight, panicle weight, spikelets panicle-1, florets spikelet-1, and panicles m-2 across six experimental environments. Significance for these response variables at the nitrogen treatment(A), taxa(B), and interaction(A*B) is depicted.

Experimental Seed Yield Harvest Thousand Seed Panicle Weight Spikelets Florets Panicles m-2 Environment (kg ha-1) Index Weight (mg) (g) Panicle-1 Spikelet-1 St. Paul 2017 Nitrogen(A) ns ns ns Taxa(B) *** *** *** A*B * ns ns Becker 2017 Nitrogen(A) ns ** ns Taxa(B) *** *** *** A*B ns ** ns Roseau 2017 Nitrogen(A) ** ns ns Taxa(B) *** *** *** A*B * ns ns St. Paul 2018 Nitrogen(A) ** ns ns ns ns ns ns Taxa(B) *** *** *** *** *** ns *** A*B ns ns ns ns ns ns ns Becker 2018 Nitrogen(A) ** * ns ns ns ns * Taxa(B) *** ** *** *** *** ns *** A*B ns ns ns ns ns ns ns Roseau 2018 Nitrogen(A) ns *** ns ** ns ns ns Taxa(B) *** *** *** *** *** ns *** A*B ** * ns ns ns ns ns *, **, ***, significant levels correspond to .05, .001, .0001, respectively, ns = not significant

Figure 1 – Seed yield is in kg ha-1. Solid and dotted line represent average Canada and Oregon seed yields, respectively. Values followed by the same lowercase letter are not statistically different at p=0.05. 54

Figure 2 – Seed yield is in kg ha-1. Solid and dotted line represent average Canada and Oregon seed yields, respectively.

Figure 3 – Seed yield is in kg ha-1. Solid and dotted line represent average Canada and Oregon seed yields, respectively.

Figure 4 – Seed yield is in kg ha-1. Solid and dotted line represent average Canada and Oregon seed yields, respectively.

Figure 5 – Seed yield is in kg ha-1. Solid and dotted line represent average Canada and Oregon seed yields, respectively. Values followed by the same lowercase letter are not statistically different at p=0.05. 58

Figure 6 – Seed yield is in kg ha-1. Solid and dotted line represent average Canada and Oregon seed yields, respectively. Values followed by the same lowercase letter are not statistically different at p=0.05. 59

Table 6 – Seed yield, harvest index and thousand seed weight of five taxa of fine fescue in St. Paul 2017.

Taxa Seed Yield (kg ha-1) Harvest Index Thousand Seed Weight (mg) Chewings none 30 .11 1059 split low 90 .11 761 low 106 .10 1021 split high 40 .09 685 high 43 .14 1003 Hard none 536 b .31 835 split low 660 ab .30 829 low 713 ab .29 792 split high 803 a .31 848 high 790 a .30 841 Strong none 336 .23 1168 split low 293 .19 1198 low 116 .15 817 split high 310 .18 1254 high 140 .20 1186 Sheep none 90 .20 518 split low 133 .16 602 low 223 .43 719 split high 140 .11 512 high 66 .16 503 Slender none 16 .08 946 split low 10 .07 1044 low 33 .11 833 split high 20 .08 869 high 16 .10 931 Values followed by the same lowercase letter are not statistically different at p=0.05.

Table 7 – Seed yield, harvest index and thousand seed weight of five taxa of fine fescue in Becker 2017.

Taxa Seed Yield (kg ha-1) Harvest Index Thousand Seed Weight (mg) Chewings none 286 .25 a 1084 split low 573 .25 a 1126 low 333 .24 a 1090 split high 313 .10 b 1001 high 350 .25 a 1116 Hard none 223 .26 952 split low 243 .19 998 low 256 .24 927 split high 420 .27 978 high 280 .20 888 Strong none 280 .23 1225 split low 400 .21 1248 low 273 .22 1194 split high 566 .20 1242 high 510 .29 1129 Sheep none 10 .06 662 split low 66 .09 673 low 16 .07 714 split high 63 .10 743 high 80 .12 670 Slender none 83 .16 a 1163 split low 186 .08 ab 1238 low 193 .18 a 1148 split high 70 .04 b 1197 high 143 .17 a 1113 Values followed by the same lowercase letter are not statistically different at p=0.05.

Table 8 – Seed yield, harvest index and thousand seed weight of five taxa of fine fescue in Roseau 2017.

Taxa Seed Yield (kg ha-1) Harvest Index Thousand Seed Weight (mg) Chewings none 1730 .26 1066 split low 1903 .26 1004 low 1760 .25 1019 split high 2163 .25 992 high 1993 .24 1020 Hard none 1493 b .36 844 split low 1656 ab .38 844 low 1886 ab .35 776 split high 1706 ab .37 819 high 1930 a .36 830 Strong none 1843 .23 1085 split low 1786 .23 1138 low 1876 .21 1087 split high 1796 .21 1073 high 1933 .21 1066 Sheep none 793b .38 625 split low 1053ab .26 674 low 826ab .28 616 split high 1056ab .25 608 high 1256a .26 614 Slender none 980 ab .19 1025 split low 1346 a .19 1053 low 1290 ab .18 1068 split high 860 b .13 1017 high 1276 ab .20 1042 Values followed by the same lowercase letter are not statistically different at p=0.05.

Table 9 – Seed yield, harvest index, thousand seed weight, panicle weight, spikelets panicle-1, florets panicle-1, and panicles m-2 of five taxa of fine fescue in St. Paul 2018.

Taxa Seed Yield Harvest Thousand Seed Panicle Weight Spikelets Florets Panicles m-2 (kg ha-1) Index Weight (grams) Panicle-1 Spikelet-1 Chewings none 568 .24 728 124 29 5 4199 split low 576 .20 806 121 28 6 4318 low 636 .20 780 128 30 5 4229 split high 551 .18 754 120 27 5 4025 high 506 .19 835 101 23 5 3902 Hard none 565 .22 704 73 10 5 5249 split low 761 .26 652 73 13 5 5706 low 818 .28 754 73 12 5 4351 split high 703 .26 762 74 17 6 7217 high 691 .21 733 95 16 6 2492 Strong none 150 .18 903 91 18 4 818 split low 178 .15 755 88 20 4 1663 low 185 .14 930 86 17 6 1692 split high 135 .15 868 82 20 5 2539 high 135 .13 881 100 23 5 1532 Sheep none 455 .25 508 65 14 5 3485 split low 456 .20 663 49 15 5 4094 low 443 .20 459 53 14 5 4213 split high 288 .16 653 59 14 6 4242 high 318 .20 432 65 14 5 4130 Slender none 361 .18 888 97 20 5 3199 split low 385 .17 731 78 17 5 3405 low 416 .20 828 90 15 4 1663 split high 130 .11 870 112 23 5 1768 high 226 .15 798 97 16 5 2228

Table 10 – Seed yield, harvest index, thousand seed weight, panicle weight, spikelets panicle-1, florets panicle-1, and panicles m-2 of five taxa of fine fescue in Becker 2018.

Taxa Seed Yield Harvest Thousand Seed Panicle Weight Spikelets Florets Panicles m-2 (kg ha-1) Index Weight (grams) Panicle-1 Spikelet-1 Chewings none 243 .31 880 103 26 5 949 split low 350 .23 873 113 26 5 1159 low 351 .23 905 93 23 5 1724 split high 223 .18 888 111 23 5 1579 high 296 .18 855 106 23 4 2710 Hard none 268 .32 799 43 12 5 3644 split low 406 .24 745 65 10 5 3521 low 483 .29 639 61 12 4 3362 split high 325 .21 809 76 15 5 4789 high 426 .25 696 63 15 5 4380 Strong none 20 .24 685 79 24 6 134 split low 18 .17 979 81 17 4 782 low 23 .08 779 65 18 5 391 split high 10 .15 852 75 19 4 126 high 31 .24 752 62 17 3 420 Sheep none 133 .25 514 46 10 5 1775 split low 168 .22 577 44 9 4 1753 low 186 .22 496 57 21 5 2210 split high 131 .14 515 46 17 6 2456 high 195 .20 462 63 14 5 2195 Slender none 53 .18 856 62 14 5 463 split low 43 .16 803 79 16 5 304 low 80 .18 886 81 18 6 786 split high 33 .20 679 100 19 7 297 high 63 .16 833 91 18 6 793

Table 11 – Seed yield, harvest index, thousand seed weight, panicle weight, spikelets panicle-1, florets panicle-1, and panicles m-2 of five taxa of fine fescue in Roseau 2018. Values followed by the same lowercase letter are not statistically different at p=0.05.

Taxa Seed Yield Harvest Thousand Seed Panicle Weight Spikelets Florets Panicles m-2 (kg ha-1) Index Weight (grams) Panicle-1 Spikelet-1 Chewings none 136 b .28 895 83 19 4 1170 split low 206 b .27 877 103 18 4 1728 low 190 b .26 877 78 16 4 1010 split high 376 a .23 913 97 17 4 2564 high 231 ab .22 936 89 18 5 2141 Hard none 375 a .39 a 759 58 10 5 2797 split low 188 b .20 b 790 64 11 5 3047 low 160 b .22 b 775 77 13 4 3141 split high 188 b .21 b 876 67 11 5 3184 high 185 b .22 b 798 77 13 5 2565 Strong none 46 .20 895 72 17 4 811 split low 70 .25 996 96 19 4 1905 low 88 .17 882 79 16 4 1130 split high 86 .13 981 98 20 4 1728 high 96 .17 967 107 20 5 971 Sheep none 98 .27 ab 546 38 12 5 2181 split low 153 .35 a 529 50 9 5 2956 low 191 .21 b 525 58 14 5 2148 split high 150 .23 ab 524 53 12 5 2623 high 158 .27 ab 502 58 13 4 2793 Slender none 18 .19 889 81 17 6 826 split low 26 .12 934 95 19 5 1003 low 26 .12 922 82 16 5 1221 split high 26 .10 957 99 20 5 1286 high 31 .22 638 104 20 5 1210 Values followed by the same lowercase letter are not statistically different at p=.05

Chapter 3: Seed Yield, Weight, and Germination of Hard Fescue (Festuca brevipila

T.) ‘MNHD’ Under Different Turfgrass Seed Production Herbicides

Introduction

The commercial value of turfgrass seed is compromised when noxious weed seeds are present. For example, in Minnesota turfgrass seed cannot be sold if prohibited weeds, such as Canada thistle (Cirsium arvense L.) are detected. Furthermore, restricted weeds, like quackgrass (Agropyron repens L.) cannot comprise more than 1% of total weight (State of Minnesota, 2015). For this reason, seed growers and processors take measures to eliminate or reduce weed seed incidence by applying effective herbicides, using cultural management practices like residue burning, and by physically removing the contaminants post-harvest. However physically removing seed is costly and not always possible, additionally burning may introduce air quality concerns and erosion (Pumphrey

1965). The responsible application of herbicides continues to be an effective method to significantly reduce weed seed incidence in turfgrass seed production.

Tolerance to effective herbicides is a quality desired in turfgrass taxa used in commercial seed production. Fine fescue turfgrass taxa, hard fescue (Festuca brevipila

T.), sheep fescue (Festuca ovina L.), Chewings fescue (Festuca rubra L. ssp. commutata), strong creeping red fescue (Festuca rubra L. ssp. rubra), and slender creeping red fescue (Festuca rubra L. ssp. litoralis) are considered for seed production in northern Minnesota due to consumer interest in the low-input characteristics they possess

(Bonos and Huff 2013). These fine-leaved turfgrasses are cool-season grass taxa that marketing research shows consumers are willing to pay a premium price for (Hugie et al.

2012, Yue et al. 2012) Moreover, they have demonstrated excellent ability to persist in a

range of minimal environments that exhibit moderate to extreme drought, shade stress, salt and ice stress, low fertility soils (Watkins et al. 2010, Bertin et al. 2009). However, when compared to other cool-season turfgrasses, like perennial ryegrass (Lolium perenne

L.) and Kentucky bluegrass (Poa pratensis L.), use is hindered by higher seed prices and limited availability. Growing these taxa for seed profitably in Minnesota would allow turfgrass consumers in North America to have more access to these sustainable turfgrasses. However, successful fine fescue seed production in Minnesota requires knowledge of efficient agronomic practices specific to this region, among these include seed purity via herbicide applications (Wyse et al. 1986, Elling 1977).

Fine fescue seed is currently produced in the Peace River Region in northwestern

Canada, Oregon, and Denmark. In northern Minnesota, seed production has been investigated but does not occur (Yoder 2000, Young et al. 2002, Wong 2019).

Historically, agronomists in Minnesota have observed commercially unprofitable yields and the infestation of noxious weed taxa like quackgrass and foxtail barley (Hordeum jubatum L.), these have discouraged potential commercial seed production. Wyse et al.

(1986) applied sethoxydim herbicide, a cyclohexanone acetyl coenzyme A inhibitor that is used to control grass weed taxa, to red fescue and reported no injury or reduction in seed yields. This tolerance has been attributed to an acetyl coenzyme A that is not susceptible to applications of up to 1 mM of sethoxydim herbicide (Stoltenburg et al.

1989). At the time, this discovery of fine fescue turfgrass’ tolerance to herbicides aimed at controlling grass taxa revived interested in producing the seed commercially. Despite this breakthrough, red fescue yields at the time were not high enough to encourage commercial production (Wyse et al. 1986).

Recently however, fine fescue turfgrass taxa have demonstrated improvements in yield in comparison to historical performance (Bonos and Huff 2013). For example, several hard fescues varietal trials conducted in at Magnusson Research Farm in Roseau

Minnesota have reported average yields between 1000 to 1200 kg ha-1, which is comparable to seed yields reported from Oregon (Elling 1977, 1978, 1981). Though growers in northern Minnesota are producing mostly perennial ryegrass and some

Kentucky bluegrass, they have shown interest in producing seed for fine fescue turfgrass taxa because of their higher seed value (Oregon Agripedia 2012, 2017). While seed yields have improved, ensuring seed value in fine fescue turfgrasses is important if commercial seed production of these turfgrasses is to be economically viable. Presently, growers in this region use a range of proven herbicides to control prevalent noxious weeds in turfgrass seed production. Although growers have experience in managing noxious weeds in turfgrass seed production systems, fine fescues turfgrasses are different taxa and may be affected differently by herbicides. Ensuring the seed purity of high yielding fine fescue taxa requires special knowledge of how these taxa are affected by common herbicides used in Minnesota for turfgrass seed production.

Therefore, before seed producers in northern Minnesota can consider producing fine fescue turfgrass taxa seed, an understanding of how applications of proven and commonly used herbicides affect these cool-season grass taxa would provide insight needed to begin commercial seed production. Specifically, seed yield, weight, and germination seed, factors that determine economic value, are of interest to seed producers because they all contribute to seed quality. Presently there is not enough research showing how herbicides treatments affect improved populations fine fescue turfgrass taxa

in seed production. The main objectives of this study were to determine if effective herbicides commonly used for weed seed control in Minnesota had adverse effects on hard fescue ‘MNHD’ seed yield, weight, and germination.

Materials and Methods

In July 2015, 1.8 x 6.1 m seed production plots of ‘MNHD’ hard fescue were seeded in Magnusson Research Farm in Roseau on Borup silt loam. Plots were seeded using a Hans-Ulrich Hege double-disk furrow opener 10 row plot seeder, a seeding of rate of 5.6 kg ha-1 was used and rows were spaced 30 cm apart. From this seeding, two harvest seasons, 2016 and 2017, of data were taken; data from these two growing seasons come from the same plots in both years. A second trial was established in 2017 under the same conditions on a different site at Magnusson Research Farm and produced one

(2018) growing season. This provided three growing seasons of data, each analyzed as a distinct experimental environment. Each fall, a fertilizer application of (60-40-40) was applied to all plots at a rate of 86.9 kg ha-1 in the form of granular urea.

The experiment was established as a randomized complete block design that included three replications of seven herbicides. Treatment 1 consisted of clethodim (2-

[(E)-N-[(E)-3-chloroprop-2-enoxy]-C-ethylcarbonimidoyl]-5-(2-ethylsulfanylpropyl)-3- hydroxycyclohex-2-en-1-one) applied at a rate of 209.9 g a.i. ha-1, treatment 2 of fluzifop-p-butyl (butyl (2R)-2-[4-[5-(trifluoromethyl) pyridin-2- yl]oxyphenoxy]propanoate) at a rate of 174.9 g a.i. ha-1, treatment 3 of mesotrione (2-(4- methylsulfonyl-2-nitrobenzoyl) cyclohexane-1,3-dione) applied at a rate of 105.4 g a.i. ha-1, treatment 4 of dicamba (3,6-dichloro-2-methoxybenzoic acid) applied at a rate of

420.5 g a.i. ha-1, treatment 5 of 2,4–D amine (2-(2,4-dichlorophenoxy)acetic acid)

applied at a rate of 398.9 g a.i. ha-1, and treatment 6 of 2,4–D amine and dicamba applied together at rates 398.9 and 420.5 g a.i. ha-1, respectively. Treatment 7 was the untreated control.

Clethodim and fluazifop-p-butyl are both group 1 herbicides that inhibit the enzyme that is involved in lipid synthesis of cells, acetyl coenzyme A carboxylase.

Clethodim is cyclohexanone herbicide and fusillade is a aryloxyphenoxy propionate herbicide. Clethodim was chosen as a substitute for sethoxydim because it is more effective at controlling monocot taxa and therefore of greater interest to growers

(Personnel Communication, Donn Vellekson). Mesotrione is a triketone herbicide in group 27, it inhibits p-hydroxyphenyl pyruvate dioxygenase (HPPD) which is involved in carotenoid biosynthesis. Dicamba and 2,4–D amine are group 4 synthetic growth hormones that mimic indole-3- acetic acid (IAA). These herbicides were chosen because they are common and effective in general turfgrass seed production in northern

Minnesota and because they provide a broad range of chemistries to test on hard fescue

‘MNHD’. (Fairey and Lefkotvicvh 2000, Zapiola et al. 2014, Young et al. 1998, Chastain et al. 2011, Chastain et al. 2014, PNW Pest Management Handbooks, Weed Science

Society of America).

Herbicide treatments were applied in mid-May of each growing season to mature swards with a bicycle sprayer at between 827 and 896 kilopascals with a paraffin-based oil surfactant. Specifically, the herbicide treatment applications were made on 20 May

2016 with approximately 20% heading, on 10 May 2017 on the early booting stage, and on 21 May 2018 at the middle boot stage for 2016, 2017, and 2018 experimental environments respectively. All these herbicide applications were made during stages 4

and 5 developmental scale (Gustavsson 2010). As a standard practice, all plots received applications of 2,4–D amine and dicamba every September at a rate of 278 g a.i. ha-1 and

420 g a.i. ha-1.

Seed yield, thousand seed weight, and seed germination were the response variables uses to assess how hard fescue ‘MNHD’ was affected by the application of the herbicide treatments in each growing season. Harvesting took place around late June to early July and was done by hand harvesting a 1 m2 quadrat within the plot that contained five rows. Samples were dried for 36 to 48 hours at 32oC and then stored at ambient temperatures. Yield samples were then mechanically threshed using either a Mater Seed

Equipment OEM, Inc. Corvallis, OR for large samples or a ALMACO belt-thresher by

Allan Machine Works Ames, IA for smaller ones. After samples had been cleaned the seed was put through a Carter-Day Inc. aspirator to remove small debris and empty seed husks. Afterward, samples were sifted using two differently sized sieves from Seedburo, a 8.6 mm and then a 6.83 mm in diameter. Processed samples were weighed to determine seed yield. Thousand seed weight was taken by counting 1000 seeds using a Diamond

Counter D-JR from Data Technologies and then weighing in milligrams using an analytical balance. Germination testing for the hard fescue was done according to the

Association of Official Seed Analysts (AOSA) standard seed rules for that taxa. This involved germinating 400 seeds from a sample in a clear container with tissue blotting that retained added moisture. The containers were incubated in a light chamber that alternated between 8 hours of cool white light (1.1 to 1.8 W m-2) at 25oC and 16 hours of darkness at 15 oC.

Data for the three experimental environments was analyzed separately due to heterogeneity of the data and analyzed using R statistical programming environment

(version 3.6.0), Importantly, for the three response variables, seed yield, thousand seed weight, and germination the data was transformed to percent of the control, that is, each data point was divided by the control in each replication to obtain a percent relative to the control; this allows a clearer comparison of the herbicide treatments to the control application of no herbicide application. In R, the packages “agricolae” and “lsmeans” were used to create the analysis of variance models and means separation analysis (Lenth

2018, Meniburu, R Core Team 2015). Function aov was used to build the analysis of variance models and function lsmeans was used to perform means separation procedure

(Lenth 2018, de Mendiburu 2019, R Core Team 2015).

Results

In the 2016 experimental environment there were significant differences in seed yield, thousand seed weight, and percent germination under the different herbicide treatments (Table 3). For seed yield, the clethodim herbicide application had a reduction of about 98% when compared to the control (Figure 1). The rest of the herbicides did not significantly reduce or increase yield. Thousand seed weight under the clethodim herbicide treatment had a 23% reduction when compared to the control (Figure 2). Under the clethodim herbicide treatment, the percent germination rate was reduced significantly by 80% (Figure 3). The rest of the herbicides did not significantly reduce or increase germination.

Data collected from the 2017 experimental environment did not have any significant differences in mean percent of the control for seed yield, thousand seed

weight, or germination under any of the herbicide treatments relative to the control (Table

3).

In 2018 experimental environment there were significant differences in seed yield, thousand seed weight, and percent germination for the treatments (Table 7). Under the clethodim herbicide treatment there was a 100 percent reduction in seed yield, thousand seed weight, and germination (Figures 7,8,9). Clethodim treatment for this harvest year produced stands with no seed. Apart from the clethodim, no other herbicide treatment had any significant effect on seed yield, thousand seed weight, and percent germination.

Discussion and Conclusions

In the experimental environments of 2016 and 2018 the clethodim herbicide treatment applications reduced hard fescue ‘MNHD’ seed yield, thousand seed weight, and percent germination significantly relative to the control. Additionally, in 2016 thousand seed weight was reduced significantly by the 2,4–D amine herbicide treatment when compared to the 2,4–D amine with Clarity herbicide treatment. However, this particular negative herbicide effect on thousand seed weight was not observed for 2017 or 2018 experimental environments. Notably, 2016 and 2018 harvest years are both first year seed production years. Since no significant differences in seed yield and quality were reported for the 2017 harvest data, which is a stand in its second year, these data analyses suggest that the hard fescue ‘MNHD’ may only be susceptible to certain herbicide stresses, in this instance clethodim, during its first year of seed production.

This phenomenon has been documented in previous studies, for example, the timing of herbicide applications is known to affect fine fescue seed production stands

(Yoder 2000, Hukting 2019). When applied to creeping red fescue in the fall of the year of establishment, 2,4–D amine had a seed yield reduction of between 25 to 50 % in the following harvest season. Furthermore, 2,4–D amine applied to red fescue at the time of flowering posed severe reductions in yields in the following year (Yoder 2000).

Interestingly, after a first year harvest, 2,4–D amine had no adverse effects on yield in the second year. These past investigations corroborate the lack of differences observed in seed yield, seed weight, and seed germination in the second year of harvest for clethodim herbicide treatments.

Nonetheless, other variables may have influenced results. In 2016, the herbicide applications were made when the stand was at 20% heading, this may have been a factor in the reduced seed yield seen that year for clethodim as it was applied at a more advanced maturity stage (Gustavsson 2010). However, in 2018, another experimental environment where clethodim reduced seed yield, weight, and germination, herbicide treatment applications were made during the boot stage before heading. The reduction in yield might be explained by the significant reduced heading observed in 2016 and 2018 by the clethodim herbicide treatment, reduced heading directly influences the number of available seed heads for pollination and mature seed.

Previous investigations reported sethoxydim as having no toxicity to red fescue

ACCase enzyme and no general phytotoxicity (Wyse et al. 1986). Sethoxydim is in the same herbicide classification as clethodim, group 1 cyclohexanedione ACCase inhibitors, but may have different effects on fine fescue based on these field experiments. In these field experiments, the clethodim had repeated detrimental effects for ‘MNHD’ hard fescue. In fact, clethodim is listed as not recommended for fine fescue production in a

Canadian publication on seed production for the Peace River Region for causing significant injury to stands (Yoder 2000). This is evidence of that although herbicides can be in the same chemical class, sethoxydim and clethodim are both cyclohexanedione group 1 ACCase inhibitors, they can have different effects on the same taxa (Stoltenburg et al. 1989). Interestingly, the fusilade herbicide treatment, which is another group 1 acetyl CoA carboxylase but in the aryloxyphenoxy propionate chemical class, had no detrimental effects on hard fescue ‘MNHD’ seed yield, thousand seed weight or germination in any experimental environment. This has been observed before in an

Italian ryegrass (Lolium multiflorum Lam.) biotype that was susceptible to clethodim but not to diclofop, which is another aryloxyphenoxy herbicide (Betts et al. 1998, Gronwald et al. 1989). Presently, the reason for susceptibility of hard fescue to clethodim but not sethoxydim is not known. It may be caused by an ACCase enzyme that is sensitive to clethodim or it may due to physiological toxicity.

The purpose of these field experiments were to determine whether proven herbicides had adverse effects on hard fescue ‘MNHD’ characteristics. Two first year hard fescue seed production establishments, 2016 and 2018, showed reductions in seed yield, seed weight, and seed germination to the clethodim herbicide treatment, and therefore it cannot be recommended for use in ‘MNHD’ seed production. The other herbicides used in this experiment appear to be safe for seed production since they had no adverse effects on ‘MNHD’ compared to the control. Lack of adverse effects for clethodim in the second year stand of 2017 suggests that hard fescue ‘MNHD’ possibly has certain herbicide susceptibilities at specific growth stages. Further experiments may

look at how yield in fine fescue turfgrass taxa are effected when proven herbicides are applied at various stand maturity levels.

Table 1 – The six herbicides used in the field experiments. Trade name, active agent, herbicide class, group, mode of action, and target pest are described.

Trade Name Active Agent Herbicide Class Group Mode of Action Target Pest Section 2 clethodim cyclohexanedione 1 Acetyl CoA grass taxa Carboxylase (monocot) (ACCase) Inhibitors Fusilade DX fluazifop-p- aryloxyphenoxy 1 Acetyl CoA grass taxa butyl propionate Carboxylase (monocot) (ACCase) Inhibitors Callisto mesotrione triketone 27 Carotenoid broadleaf taxa Biosynthesis (dicot) Inhibitor Clarity dicamba benzoic acid 4 Synthetic Auxin broadleaf taxa (dicot) 2,4–D amine 2,4–D amine phenoxy acid 4 Synthetic Auxin broadleaf taxa (dicot)

Table 2 – Listed are the seven herbicide treatments used in the field experiments. Chemical, application rate, and percent surfactant are described. Treatments one through five consist of a

single herbicide while treatment six is a combination of 2,4–D amine and Clarity. Treatment seven was a control application of no herbicide.

Herbicide Treatment Chemical Application Rate Percent surfactant g a.i. hectare 1 Clethodim 209 1% 2 Fusilade 174 1% 3 Callisto 105 2.5% 4 Clarity 420 1% 5 2,4–D amine 398 1% 6 2,4–D amine + Clarity 398 + 420 1% 7 nh* nh nh * = no herbicide

Table 3 - Analysis of variance for yield, thousand seed weight, and percent germination for the three experimental environments.

Experimental Yield (kg ha-1) Thousand Seed Weight Percent Germination Environment (grams) 2016 Replication ns ns ns Herbicide *** *** *** 2017 Replication ns ns ns Herbicide ns ns ns 2018 Replication ns ns ns Herbicide *** *** *** *, **, ***, significant levels correspond to .05, .001, .0001, respectively, ns = not significant.

Figure 1 – Percent values above or below 100% are performance relative to the control. Significant differences at the p=.05 are indicated by different lowercase letters. 80

Figure 2 – Percent values above or below 100% are performance relative to the control. Significant differences at the p=.05 are indicated by different lowercase letters. 81

Figure 3 – Percent values above or below 100% are performance relative to the control. . Significant differences at the p=.05 are indicated by different lowercase letters. 82

Figure 4 – Percent values above or below 100% are performance relative to the control. Significant differences at the p=.05 are indicated by different lowercase letters.

Figure 4 – Percent values above or below 100% are performance relative to the control. . Significant differences at the p=.05 are indicated by different lowercase letters.

Figure 5 – Percent values above or below 100% are performance relative to the control. . Significant differences at the p=.05 are indicated by different lowercase letters. 85

Figure 6 – Percent values above or below 100% are performance relative to the control. Significant differences at the p=.05 are indicated by different lowercase letters. 86

Figure 7 – Percent values above or below 100% are performance relative to the control. . Significant differences at the p=.05 are indicated by different lowercase letters. 87

Figure 8 – Percent values above or below 100% are performance relative to the control. . Significant differences at the p=.05 are indicated by different lowercase letters. 88

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