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United States Department of Agriculture

Agricultural Research Service

Title: Registration of Orarhr-G93 and Orarhr-M93 Italian Ryegrass Germplasm with Tolerance to Diclofop-Methyl

Authors
item Barker, Reed
item Mueller Warrant, George
item Banowetz, Gary
item Roush, M - OSU, CORVALLIS, OR
item Maxwell, B - OSU, CORVALLIS, OR
item Griffith, Stephen
item Radosevich, S - OSU, CORVALLIS, OR

Submitted to: Crop Science
Publication Type: Germplasm Release
Publication Acceptance Date: March 5, 1997
Publication Date: N/A

Interpretive Summary: Two Italian ryegrass germplasms, ORARHR-G93 and ORARHR-M93, with high levels of tolerance to the herbicide Hoelon were developed by personnel at the USDA-ARS National Forage Seed Production Research Center and from Oregon State University. The two germplasms were developed through a backcross selection program to obtain populations differing from parental cultivars in genes conditioning tolerance to the herbicide when it is applied at recommended field application rates. Hoelon is in a class of herbicides developed to control grasses in broadleaf crops and some cereals. These germplasms will be useful for further breeding and for studies on development of herbicide tolerance in grasses. In one study, ORARHR-G93 had 76.0% surviving plants, ORARHR-M93 had 84.2%, compared to less than 3.0% for twelve common cultivars. With four crosses to the recurrent parent, and by using 60 or more different plants in each crossing cycle, ORARHR-G93 AND ORARHR-M93 should be 93.75% genetically similar to Gulf and Marshall, respectively. Seed will be stored by the USDA-ARS National Forage Seed Production Research Center and limited quantities of each germplasm made available upon request.

Technical Abstract: Two Italian ryegrass (Lolium multiflorum Lam.) germplasms, ORARHR-G93 and ORARHR-M93, with high levels of tolerance to diclofop-methyl {(+) - 2 - [4 - (2,4 - dichlorophynoxy) phenoxy] propanoic acid} were developed by personnel at the USDA-ARS National Forage Seed Production Research Center and from Oregon State University. The two germplasms were developed through a backcross selection program to obtain isofrequent populations differing from parental cultivars in frequency of genes conditioning tolerance to the herbicide diclofop when applied at recommended field application rates. Diclofop is an aryloxyphenoxyproprionate, a class of herbicides developed to control grasses in broadleaf crops and some cereals. These germplasms will be useful for further breeding and for studies on development of herbicide tolerance in grasses. In one study, ORARHR-G93 had 76.0% surviving plants, ORARHR-M93 had 84.2%, Gulf 2.2%, Marshall 1.9%, 'Aubade' 3.8%, 'Passeral' and 'Tetrelite' 3.0%, 'Bison' 2.6%, 'Prominade' 2.0%, 'Jackson' 1.5%, 'Caramba' 1.0%, 'Surrey' 0.9%, 'Florida 80' 0.4%, and 'Multimo' 0%. With four crosses to the recurrent parent, and by using 60 or more different plants in each crossing cycle, ORARHR-G93 and ORARHR-M93 should be 93.75% genetically similar to Gulf and Marshall, respectively. Seed will be stored by the USDA-ARS National Forage Seed Production Research Center and limited quantities of each germplasm made available upon request

Last Modified: 12/22/2014
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