|Chastain, T - OSU, CORVALLIS, OR|
Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: September 17, 1997
Publication Date: N/A
Interpretive Summary: The management of ryegrass in pastures, lawns, or for seed is based on sound knowledge of how plants grow from the time they are vegetative until they make seed. Several features of ryegrass plant structure play critical roles in growth, development, and productivity. One important feature is the tiller, branch or shoot, on a ryegrass plant. It is the tiller that is considered a fundamental unit of the ryegrass stand. The fate of tillers is the major determinant of productivity in ryegrass plant populations. Similarly, physiological and genetic factors influencing ryegrass flowering and seed development can equally impact grass seed production agriculture. For example, if ryegrass from a northern latitude is grown in a more southern latitude, then factors that trigger flowering may not be present. This would have a dramatic impact ryegrass reproduction by seed.
Technical Abstract: The management of economic yields of Lolium spp. in grassland agriculture depends on sound knowledge of plant growth and development from vegetative to floral to seed. Ryegrass is noted for exceptional seedling emergence and stand establishment. Tiller development is a key event in ryegrass development. Leaves and tillers are produced according to a predetermined sequence and is directly related to accumulated heat units. The rate of leaf appearance in ryegrass has a strong influence on tiller production since the number of auxiliary buds that are initiated to form tillers is related to leaf appearance. The growth environment, as affected by both the natural climatic and edaphic conditions and the influence of management practices, can modify the growth and development of ryegrass. Irradiance and temperature are the most important environmental parameters affecting photosynthesis and hence growth and development. Among Lolium spp. a continuous gradient of floral induction requirements exist. Much of the difference in induction requirements for a population or closely related species is related to past climatic and agronomic selection.