b'A New Tool cells, which does not involve foreign DNA. In an aside, Schwartz says breeding for Breeding turfgrasses relies on traditionalThis was the first time anyone hasshade tolerance has been more important methods for developing improved spe- come up with a method to deliver thethan he would have expected, as some of cies and varieties as there is reluctanceCas9 protein through lipofection intothe most high profile stadiums have seat-amongst the public to accept plants andplant cells, Liu says. Our major achieve- ing that casts a fair amount of shade.seeds that have been subjected to somement was to make that happen. Low light intensity and poor air move-form of genetic modification. ment in sports arenas can cause addi-However, Munshaw reports thatThoughtful Breeding Efforts tional disease pressures, says Fricker. In researchers at North Carolina StateBreeding turfgrasses for athletic fields andshady areas, the grass can be weakened University have developed a new way tovarious sporting activities is usually a bitby etiolation as it reaches for height.get CRISPR/Cas9 into plant cells withoutdifferent than breeding for the home lawn.As sports organizations, municipali-inserting foreign DNA. This allows forFor our breeding program, saysties and others move away from artificial precise genetic deletions or replacementsSchwartz, the difference lies in the finalturf, the demand for tough, resistant and with the end product not being a geneti- selection pressure for specific situations.durable grasses will provide an unrelent-cally modified organism (GMO). We dont test all 5,000 new hybrids weing market for the seeds developed by Specifically, CRISPR/Cas9 is a tool thatmake each year for wear tolerance. Weprivate and public turfgrass breeders. can be used to precisely cut and removenarrow the number that we eventuallyThe amount of testing and develop-or replace a specific genetic sequence. Thetrial by first selecting for adaptation toment that goes on before a variety goes Cas9 protein serves as a pair of molecularTifton, then for drought tolerance, thento market is a years-long, capital inten-scissors, guided to the specific geneticfor mowing response. Only then wouldsive effort aimed at offering end users a target by an easily swapped RNA guide. we trial the top 10-50 hybrids from eachproven product, Cain says. It is common In a recent study, Wusheng Liu, around of crossing for athletic field use. for this process to take over a decade.plant biologist and biotechnologist in theThe final difference, Schwartz says, isIf turfgrasses today, through thought-Department of Horticultural Science atthe collaborators you work with towardsful breeding, are 10 times better than they North Carolina State University, dem- the end. For example, we would try towere 10 years ago, it will certainly be inter-onstrated a new way of introducing theput out a few experimental athletic fieldsesting to see where turfgrasses will be ten Cas9 protein and guide RNA into plantprior to release.years from now.SWOCTOBER 2021SEEDWORLD.COM /13'