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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 #155311

Title: METHODS OF INOCULATION OF SUNFLOWER HEADS WITH SCLEROTINIA SCLEROTIORUM

Author
item VAN BECELAERE, G
item Miller, Jerry

Submitted to: Helia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/22/2004
Publication Date: 12/1/2004
Citation: Van Becelaere, G., Miller, J.F. 2004. Methods of inoculation of sunflower heads with Sclerotinia sclerotiorum. Helia. 27(41):137-142.

Interpretive Summary: Sclerotinia head rot is a major disease of sunflower. The development of hybrids with adequate genetic resistance is necessary to reduce yield losses. The objective of this study was to find an effective technique of inoculating sunflower heads with Sclerotinia sclerotiorum for screening and identifying resistant and susceptible genotypes. A factorial experiment was conducted to evaluate the effectiveness of different inoculation procedures. The factors were bag color, water treatment, inoculum type, and rate of inoculation. Based on the results of this study, the inoculation procedure recommended to sunflower researchers who wish to screen lines or hybrids for Sclerotinia head rot resistance would be spraying the heads at the beginning of flowering with 5 mL of a suspension of ascospores containing 5000 ascospores per milliliter and covering the heads with brown paper bags immediately after inoculation. Application of additional water to the inoculated heads on two days following inoculation would not be needed. Measurements of infection could begin as soon as 35 days after inoculation.

Technical Abstract: Sclerotinia head rot, caused by Sclerotinia sclerotiorum (Lib.) de Bary, is a major disease of sunflower (Helianthus annuus L.). The development of hybrids with adequate genetic resistance is necessary to reduce yield losses. The objective of this study was to find an effective technique of inoculating sunflower heads with Sclerotinia sclerotiorum for screening and identifying resistant and susceptible genotypes. A factorial experiment was conducted to evaluate the effectiveness of different inoculation procedures. The factors were bag color, water treatment, inoculum type, and rate of inoculation. Based on the results of this study, the inoculation procedure recommended to sunflower researchers who wish to screen lines or hybrids for Sclerotinia head rot resistance would be spraying the heads at the beginning of flowering with 5 mL of a suspension of ascospores containing 5000 ascospores per milliliter and covering the heads with brown paper bags immediately after inoculation. Application of additional water would not be needed. Measurements of infection could begin as soon as 35 days after inoculation.