34 SportsTurf | July 2016 www.sportsturfonline.com
FIELD SCIENCE
BY DAVID R. HUFF, PHD
S
eed serves as a remarkable means of plant
propagation, particularly in terms of commercial
application of plant material. It ships well, it stores
well, and large-scale establishment can be achieved
relatively quickly at low cost. In the turfgrass industry, it
is most typical that cool-season species are propagated by
seed, whereas warm-season turfgrass species are propagated
vegetatively through either sprigs or sod. While there
are exceptions to this general tendency (i.e., vegetatively
propagated cool-season species and seeded warm-season
species), for the most part, our industry uses seed to establish
cool-season turfgrass species like bentgrass, perennial
ryegrass, tall fescue, Kentucky bluegrass and fine fescues,
while vegetative propagation is commonly used for warm-
season species like bermudagrass, St. Augustine grass,
zoysiagrass and seashore paspalum.
Much has been written about using seed as a means of
turfgrass propagation, including the basic importance of
various aspects like purchasing, applying and establishing
seed; for example, being able to properly understand and use
the important information contained on a seed label like the
calculation of the percent Pure Live Seed (PLS) for comparing
the true costs of different seed products (example, see
http://plantscience.psu.edu/research/centers/turf/extension/
factsheets/seed).
However in this article, I would like to present some of
the different, though no less important, aspects of using
seed to establish areas of turf. For example, over the years,
I have found that most turf managers view their seed as an
individual cultivar or variety, in that all the seed in a bag, of
say "Penncross" creeping bentgrass, is genetically all the same.
The truth is that each individual seed gives rise to a genetically
unique individual plant. By genetically unique, I mean that
some plants will be big and others small, some will be dark
green and others light green, some will tiller more while other
stay less dense, etc. This is because each seed in the bag was
the result of a fusion between a sperm from the pollen-donator
parent plant and an egg from the seed-bearing parent plant. And
just as in animals, insects and human beings, each individual is
genetically unique and different from all others because each
was derived from a unique combination of sperm and egg that
gives rise to their genetic uniqueness.
A NUMBERS GAME
I often like to tell my students that there are more stars in
the universe than all the grains of sand on all the beaches
of planet Earth and that there are more genetically different
individuals of Penncross creeping bentgrass than there are
SEED: WHAT'S IN THE NUMBERS?