Ryegrass germination

In 1963, Fletcher and Renney (.2) detected a plant growth inhibitor in knapweed and they suggested an allelopathic role for the substance(s) that could promote the spread of knapweed. Although these results are widely quoted, the inhibitor has never been identified nor has its existence been confirmed. Twenty years later, knapweed allelopathy was reexamined in our laboratory. A series of diffuse knapweed isolates were found to be inhibitory to ryegrass germination in petri dish assays... 

Parallel studies of extracts and mixtures of compounds isolated from ragweed, Ambrosia artemisiifolia L., were also made. Water extracts of ragweed proved highly inhibitory of seed germination. Mixed sesquiterpenes isolated from ragweed were very inhibitory of onion, oat, ryegrass, and Palmer amaranth germination when applied in a dichloromethane solution pretreatment. 

The most concentrated (1 16, w/w) extract inhibited only lettuce, tomato, and ryegrass. The osmolarity of the solution was 40.3 mOsm, insufficient to affect germination of most seeds (2). 

Dilution to 1 20 eliminated inhibition in onion, oat, ryegrass, red clover, and cheatgrass. Further dilution to 1 40 limited inhibition to lettuce, carrot, and Palmer amaranth. At this concentration lovegrass germination was promoted. The addition of 0.1%... 

Crimson Clover Legume Annual Aug. 15 Sept. 15 1/2 lb. Does well in mixture of ryegrass. Hard seed may germinate over several years. 

Burnet, M.W.M., J.T. Christopher, J.A.M. Holtum, and S.B. Powles (1994). Identification of two mechanisms of sulfonylurea resistance within one population of rigid ryegrass (Lolium rigidum) using a selective germination medium. Weed Sci., 42 468 173. 

Nurse Crops—Plant species (usually annuals) which germinate quickly and grow rapidly are sometimes planted with a perennial crop to provide competition with weeds and allow the crop to become established. The nurse crop is then harvested or ranoved to allow the perennial crop to take over. For example, oats are sometimes used as a nurse crop to help establish alfalfa or clover. Annual ryegrass is sometimes used in mixtures to provide a nurse crop for perennial rye, fescue, or bluegrass. 

Welty RE, Azevedo MD, Cooper TM. Influence of moisture content, temperature, and length of storage on seed germination and survival of endophytic fungi in seeds of tall fescue and perennial ryegrass. Phytopathology 77 893-900, 1987. 

Petroski RJ, Dombos DL Jr, Powell RG. Germination and growth inhibition of annual ryegrass (Lolium multiflorum L.) and Alfalfa (Medicago sativa) by loline alkaloids and synthetic N-acylloline derivatives. J Agric Food Chem 38 1716-1718, 1990. 

Certified, Pre-Basic and Basic seeds of oilseed and turnip rape have a minimum analytical purity of 98% and a minimum germination of 85%. The maximum content by weight of other seed species is 0.3%. There are also specific standards applied for wild oats, dodder, dock, wild radish, black-grass and flaxfield ryegrass contamination. 

There are many new varieties of ryegrass with rapid establishment in cool climates, developed for sports turf they are in use for racecourses and polo grounds to repair, renew and renovate swards that have heavy use. For winter National Hunt racecourses, pre-germination enables divots to be renovated within 2 weeks in temperatures as low as 3 °C. Some of these sports turf varieties will even germinate in soil temperatures as low as 3.5 °C. ... 

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