Gene Transfer to Plants Within a decade of the first recoveries of transgenic "model" plants, gene trans- fer is an established and routine technique in numerous laboratories around the world. It contributes to the rapid progress in basic and applied plant sciences in disciplines as diverse as biochemistry, physiology, developmental biology, breeding, food sciences, and biotechnology (Lindsey 1992; Willmitzer and Topfer 1992; Kishore and Somerville 1993; Nessler 1994). Following years of unsuccessful experiments with variations in feeding iso- lated DNA to plant tissues and organs, gene transfer became a reality soon after it was discovered that the soil bacterium Agrobacterium tumefaciens contained a plasmid, part of it being transferred to competent plant cells (see Hooykaas; Introduction I: Agrobacterium tumefaciens, a natural vector system). Host range limitations of Agrobacterium-mediated gene transfer prompted the search for alternative gene transfer systems, leading soon to the development of "direct gene transfer to protoplasts" (see Potrykus; Introduction III: Direct gene trans- fer to protoplasts). Further limitations in both gene transfer systems led to the exploration of a great variety of further approaches such as pollen transforma- tion, pollen tube pathway, electrophoresis, microlaser, liposome-fusion and -injection, macroinjection, direct DNA application in numerous variations, etc. None of these approaches has, so far, been developed to a reproducible gene transfer technique and it is questionable whether they ever led to transformation (for a detailed assessment see Potrykus 1990).

Worldwide, acreage under grassland is estimated to be twice that of cropland. Two closely related genera, Festuca L. (fescues) and Lolium L. (ryegrasses) are of significant value in temperate grasslands. These genera (tribe Poeae, subfamily Pooideae) contain well-adapted, very productive grasses widely distributed in temperate and cool climates in Europe, North and South America, North, East and South Africa, Asia, Australia and New Zealand, where they are used for agricultural and recreational purposes (Jauhar 1993). They are important for grazing, stabilizing soil for agriculture, and enhancing the environment through multiple uses, such as forage, conservation and turf (Barnes 1990). Therefore, in the family Poaceae, the Festuca-Lolium group of grasses is among the most extensively studied by agronomists, plant breeders, animal scientists, taxonomists and cytogeneticists. The potential of biotechno- logical approaches has been recognized for the development of improved fescue and rye grass cultivars (Barnes 1990; Kau11990; Jauhar 1993). 1. 1 Agronomic Importance of the Festuca-Lolium Complex The Festuca-Lolium complex involves some well-adapted, highly productive persistent species which are widely used for soil stabilization, for agricultural purposes and as amenity grasses. For temperate grasslands, tall fescue, meadow fescue, Italian ryegrass and perennial ryegrass are particularly impor- tant species which show complementary desirable traits, such as palatability and fast initial growth of the ryegrasses, and winter hardiness, persistency combined with continued high production after the second harvest year of the fescues.