12 SportsTurf | June 2013 www.sportsturfonline.com

FieldScience | By Leah A. Brilman, PhD

TURFGRASS BREEDERSmay have a more difficult jobthan most other plant breed-ers. For the most part theydeal with more than one

species, usually at least four major speciesand many minor ones, and a vast geo-graphic area for each species. What alsocomplicates the breeding for the seedpropagated species is breeders must breedat the same time for turf quality, diseaseresistance and other characteristics for turf

performance and also for seed yield. Most turfgrass species are cross-polli-

nated, self-incompatible species, whichmeans the same plant cannot be the motherand the father. This makes development ofinbred lines for hybrids or seed propagatedvarieties with one genotype unfeasible.Breeders must cross similar plants togetherto start the breeding process selected for thecharacteristics desired in the new cultivar.This means traditional breeding operates asa form of population improvement, with

each individual seed in a variety geneticallyrelated to but distinct from others. By tak-ing the portion of the population with thebest of a certain characteristic, darkestgreen, highest stress tolerance, least disease,and crossing these together the breedermoves the mean of that characteristic up.The selected plants must still match for

Turfgrass breeding for sports

SELECTED PERENNIAL RYEGRASS plantsplaced into an isolation cage for crossing.

Improvement of turfgrassvarieties is dependent onbeing able to efficientlyscreen large numbers ofplants for the desiredcharacteristic(s).

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many other characteristics such as color, date of seedhead appear-ance and height to make a uniform variety.

Kentucky bluegrass is the exception due to its apomictic repro-duction. It is hard to get hybrids, with often only 10% of plants ina cross being the hybrids, the rest being genetically identical to themother plant. These hybrids usually have all the chromosomes ofthe mother plant and about half of the father. Each plant is a shotin the dark but if you do get a good plant that is apomictic theprogeny will all be the same and it can be a new variety.

The general outline for breeding is1. Establish a goal (Improved wear tolerance, diseases resistance)2. Decide how to screen for improvements ( Select in turf trials

or spaced plants)3. Screen a large number of plants and select the best ones4. Cross these plants together letting wind scatter the pollen

(small crossing cages or bigger blocks of related plants), harvestseed, plant new trials

5. Evaluate progeny for selected improvement (perhaps selectbest plants again)

6. Seed from best plants or lines bulked together as BreederSeed

7. Breeder Seed used to plant first seedstock field and enterinto NTEP and other trials

8. Seedstock (Foundation) seed used to plant Certified fields Improvement of turfgrass varieties is dependent on being able to

efficiently screen large numbers of plants for the desired characteris-tic(s). The selected plants need to be crossed together and the prog-eny (offspring) evaluated again for the characteristic(s). If thecharacteristic is highly heritable the majority of the population maythen have the characteristic or additional cycles of selection must beperformed. Due to the complex inheritance of many desired charac-teristics being able to concentrate many of them in one population orvariety is often difficult. It is often necessary to evaluate the selectedplants and progeny over a number of years and environments to reli-ably screen for some characteristics. Screening for wear tolerance was

BREEDER BLOCK OF TALL FESCUE. Seed from the isolated plantsare planted in the greenhouse and spaced plants are established into aBreeder block (each row has plants derived from one plant). Look for uni-formity and seed yield or these progeny. Usually also planted in turfplots. Poor performers will have the whole row eliminated.

often difficult since the size and speed of themachines made it difficult to screen largenumbers of turf plots. Recently Rutgers Uni-versity developed the Rutgers Wear Stimula-tor (Turf Slapper) that can apply wear over alarge number of plots and has enable weartolerance and recovery to be more easily inte-grated into varietal development. Tall fescues with improved wear tolerance

and the ability to demonstrate wear toleranceas younger plants has been a recent emphasis.Recent information by Dr. David Miner ofIowa State University suggests that additionof large seed quantities early in the season,even with wear applied, increases the percent-age of tall fescue, perennial ryegrass or Ken-tucky bluegrass in the stand. Increasedestablishment occurred at rates up to 200kg/ha for perennial ryegrass and 40 kg/ha for

Kentucky bluegrass. Tall fescues were onlyslightly less effective than perennial ryegrassin establishing during play. Additional breed-ing work in tall fescues has emphasizeddrought tolerance as well as brown patch re-sistance in multiple locations, for durable re-sistance.Perennial ryegrass breeding in the United

States for many years has emphasized darkergreen dwarf varieties with high turf quality.An important new characteristic has been thediscovery and incorporation of genes for re-sistance to gray leaf spot disease, which is thesame pathogen as rice blast disease, and hasdecimated stands of Perennial ryegrass breed-ing in the United States for many years hasemphasized darker green dwarf varieties withhigh turf quality.perennial ryegrass in thetransition zone of the United States. A bal-

14 SportsTurf | June 2013 www.sportsturfonline.com

FieldScience

KENTUCKY BLUEGRASS BREEDER BLOCK.Very uniform due to high apomixis.

KENTUCKY BLUEGRASS TRIALS at Rutgers University with wear done on front half of each plot. Cultivar names are in the back of the plot.

Perennial ryegrass breedingin the United States for manyyears has emphasized darker

green dwarf varieties withhigh turf quality.

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ance must be achieved between resistanceto this disease and resistance to other im-portant pathogens such as brown patchand red thread. Wear tolerance as a majorcomponent in selecting new ryegrasses.Breeders have been crossing more winter-active wear tolerant ryegrasses with Ameri-can germplasm to increase the weartolerance during the colder months. An ad-ditional high priority in perennial ryegrassbreeding has been salt tolerance. This isdue to the increasing use of effluent waterin many golf courses in the United Statesand elsewhere.

Hybrids of Texas bluegrass and Ken-tucky bluegrass have the potential to ex-pand the range of Kentucky bluegrass.Many of these are more heat and droughttolerant than traditional Kentucky blue-grasses, although some new cultivars ofKentucky bluegrass have also been selectedfor more heat and drought tolerance. Theother major advantage of these hybrids istheir extensive rhizomes systems. In weartrials they have shown excellent wear toler-

ance, rapid recovery and more winter-activegrowth making them better suited for manyapplications.

In breeding of all species seed yield isjust as important as diseases resistance orturf quality. Often if you find cultivars orexperimentals that are only on the market ashort time or are never marketed it is dueto inadequate seed yield. We must oftencycle one generation for a turf characteris-tic and then another for seed yield. Turfbreeders have been very successful in im-proving turf quality and seed yield at thesame time but we may not find that true inthe future.

Development of new turf cultivars takesmany steps and the diverse needs make itdifferent from many other crops. Turf breed-ers must have patience and understand themany needs of customers plus seedgrowers. n

Dr. Leah A. Brilman is the director of re-search and technical services for Pickseed/SeedResearch of Oregon, www.sroseed.com.

PURE SEED COMPANY seed yield trials for Ken-tucky bluegrass. Wide variability in maturity and ap-pearance. Only a small fraction of these will make itto market.

WEAR TRIALS on tall fescues at Rutgers Univer-sity July 2011. New tall fescues are more wear toler-ant even under heat stress.