Vol. 51—1997 - NorthEastern Weed Science Society

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Htrbicide resistant turfgrasses: potential and concerns
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Peter R. Day and Lisa Lee 1,2
b~tgraSs (Agrostis palustris Huds.) is a self-sterile outbreeding perennial grass
Crewing
that reproduces clonally by stolons. It belongs to the genus Agrostis which has many species.
Creeping bentgrassha, stolonifera L., A. palustris Huds.) is native to Eurasia but has become
naturalized in North America. Plants of creeping bentgrass spread close to the soil surface by long,
leafy stolons which Iare capable of rooting and developing new plants at each node.
The commoa name bentgrass is applied to all turfgrasses within the genus with the
exception of redtop! (A. alba.). The growth habits of bentgrass vary from a bunch type with limited
stoloniferous growt/h to forms that establish extensive stolon systems. Bentgrass is one of the most
tolerant cool seasoti turfgrassess which, because of its prostrate growth habit, can tolerate
continuous, close mowing at heights as low as 0.2". When closely mowed, bentgrass can form an
extremely fine textured, dense, high quality and uniform turf which meets the exacting standards
of golf course greens keepers. Its fine leaves, prostrate habit and tolerance to very low cutting
heights have made ~t the principal species used for putting greens and fairways on the golf courses
of temperate climatesaround the world. It is established in these locations by sowing seed on very
carefully prepared ~d levelled seed beds. In North America annual seed production of the
species, Principall~ in Oregon and Washington, approximates 3-4 million pounds.
Creeping bentgras1 regeneration and transfonnation
To transform creeping bentgrass, we developed a tissue culture regeneration system. About
6 - 8 weeks after surface sterilized seeds were placed on callus initiation medium, embryogenic
callus cultures were selected from germinating seedlings. Depending on thecultivar used, between
5-30% of seeds ca~'produce embryogenic callus cultures. Upon transfer. to regeneration medium
(MS medium with ut hormone), from 200-400 plants can be obtained from each gram (fresh
weight) of callus. . allus cultures were used to establish suspension cultures by placing
approximately 1-2 rams of callus into liquid MS medium (5Oml) in 250 ml flasks in the dark on a
rotary shaker (l25 Irpm). By subculturing to fresh medium twice a week, suspension cultures with
small cell clusters ~ere established for transformation. Both embryogenic callus and suspension
cultures were usedl as target tissues in transformation.
. ..' . was carried out using a Bio-Rad PDS-lOOOlHe Biolistic Delivery
System. This devi uses a pulse of helium at high pressure to accelerate very small (1-3 u) metal
particles coated w', transforming DNA to hit target plant cells placed in their path. Target tissues,
either suspension