Submitted to: Crop Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/30/2003
Publication Date: 1/1/2004
Citation: Kindiger, B.K., Fujiwara, T., Kobashi, K., Mizuno, K. 2004. Registration of 'Shiwasuaoba' annual ryegrass. Crop Science. Volume(44):344-345. Interpretive Summary: Few cool-season forage grasses, perennial or annual, can be utilized in rotations with summer crops such as vegetables. Cooperative USDA-ARS forage performance trials at the Grazinglands Research Laboratory, El Reno, OK, the South Central Agricultural Laboratory, Lane, OK and the Japanese National Grassland and Livestock Research Institute, have identified productive and nutritious annual ryegrass germplasm which is 3 weeks earlier in maturity than varieties normally grown in the Southern Plains Region. Forage performance evaluations indicate fall and spring biomass production is competitive to later maturing varieties such as Marshall annual ryegrass and Linn perennial ryegrass. In addition, cytogenetic investigations of this germplasm revealed the unusual possession of varying numbers of additional chromosomes, also called supernumerary or B-chromosomes. The presence of these chromosomes may have value in genetic or Lolium-Fescue hybrid breeding programs. For agricultural purposes, the early maturity of this material offers crop producers in the Southern Plains the opportunity to utilize this germplasm as a fall and winter forage or as an early hay crop. Following maturity, the ryegrass pasture can be rapidly converted to till or no-till production of summer crops. The germplasm also has potential in blends with later maturing annual ryegrass varieties to enhance early forage production.
Technical Abstract: Few cool-season forage grasses, perennial or annual, can be utilized in rotations with summer crops such as vegetables. 'Shiwasuaoba' annual ryegrass (Lolium multiflorum L.) (Reg. No. PI 632337, NSSL 422765.51) is an early maturing, diploid form which carries several B-chromosomes. It is a leafy forage cultivar capable of producing early yields which are comparable to Marshall annual ryegrass. In Oklahoma, fall and spring forage performance trials indicate that Shiwasuaoba has superior spring yields and competitive fall yields when compared to varieties of Marshall and Linn ryegrass. Total yearly biomass production of Shiwasuaoba is approximately 60% of Marshall and Linn annual ryegrass. The distinctive feature of this variety is its extremely early maturity and early fall and spring forage production potential. Shiwasuaoba flowers three weeks earlier when compared to Marshall annual ryegrass and Linn perennial ryegrass. The extremely early heading date of this variety makes Shiwasuaoba a useful variety for growers interested in a cool-season grass forage that is rapid in growth, nutritious and palatable to livestock. In addition, Shiwasuaoba may be useful for livestock grazing or haying then quickly removed for the sowing of no-till summer crops such as vegetables and melons. It is also suggested for use in blends with later maturing annual ryegrass varieties to enhance the early forage production potential.