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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Sunflower and Plant Biology Research » Research » Publications at this Location » Publication #209763
Title: Sources of resistance to a new strain of Verticillium dahliae on sunflower in North America-2006

Author
item Radi, Scott
item Gulya Jr, Thomas

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 3/1/2007
Publication Date: 3/1/2007
Citation: Radi, S.A., Gulya Jr, T.J. 2007. Sources of resistance to a new strain of Verticillium dahliae on sunflower in North America-2006. 29th Sunflower Research Workshop, January 10-11, 2007, Fargo, ND. Available: http://www.sunflowernsa.com/research/research-workshop/documents/Radi_Verticillium_07.pdf

Interpretive Summary: In 2004, a new strain of Verticillium dahliae was identified in North Dakota and Minnesota and was designated NA-V2, which overcomes the V1 resistance gene in current sunflower hybrids. Greenhouse trials were conducted in 2004 and field trials were conducted in 2005 and 2006 to evaluate sunflower germplasm for resistance to this new strain. Greenhouse needle inoculation experiments included 109 current commercial hybrids and 112 Plant Introductions (PI) from the USDA-ARS sunflower core collection. Of the 221 entries, 27 were rated resistant (<1 on a 0-4 scale) and selected for field trials. Disease testing was conducted in fields naturally infested with V. dahliae and by artificial needle inoculation in separate trials. Two entries, PI 507901 and Interstate 4575 NS, were rated resistant in greenhouse trials, and in both years of field trials. PI 507901 and Interstate 4575 NS underwent additional Verticillium resistance evaluation at four locations in Argentina, and were rated moderately susceptible, suggesting the predominant Argentine strain is different from that in North America.

Technical Abstract: In 2004, a new strain of Verticillium dahliae was identified in North Dakota and Minnesota and was designated NA-V2, which overcomes the V1 resistance gene in current sunflower hybrids. Greenhouse trials were conducted in 2004 and field trials were conducted in 2005 and 2006 to evaluate sunflower germplasm for resistance to this new strain. Greenhouse needle inoculation experiments included 109 current commercial hybrids and 112 Plant Introductions (PI) from the USDA-ARS sunflower core collection. Of the 221 entries, 27 were rated resistant (<1 on a 0-4 scale) and selected for field trials. Disease testing was conducted in fields naturally infested with V. dahliae and by artificial needle inoculation in separate trials. Two entries, PI 507901 and Interstate 4575 NS, were rated resistant in greenhouse trials, and in both years of field trials. PI 507901 and Interstate 4575 NS underwent additional Verticillium resistance evaluation at four locations in Argentina, and were rated moderately susceptible, suggesting the predominant Argentine strain is different from that in North America.