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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 #155267
Title: INHERITANCE OF THE WIDE-RANGE DOWNY MILDEW RESISTANCE IN THE SUNFLOWER LINE RHA 419

Author
item VEAR, F - INRA,CLERMONT-FERRAND, FR
item TOURVIEILLE DE LABRO, D - INRA, FRANCE
item MILLER, JERRY

Submitted to: Helia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/6/2003
Publication Date: 12/1/2003
Citation: Vear, F., Tourvieille De Labrouhe, D., Miller, J.F. 2003. Inheritance of the wide-range downy mildew resistance in the sunflower line RHA 419. Helia. 26(39):19-24.

Interpretive Summary: Downy mildew of sunflower is a worldwide disease, with at least 15 races now reported. Up to the present, downy mildew has been controlled successfully by the fungicide Apron. However, new races have evolved which attack sunflower with only Apron fungicide applied, and new fungicides have only been partially effective in their control. Therefore, genetic resistance is a major objective of sunflower researchers worldwide. Resistance to downy mildew derived from the USDA inbred sunflower line RHA 419 was studied in F2 and testcross progenies from crosses with a susceptible line and with lines carrying known resistance genes. The cross with a susceptible line indicated that RHA 419 had one dominant gene imparting resistance to races 304 and 710. The progenies from crosses of RHA 419 with lines carrying Pl5, Pl6, Pl7, or Pl8 all showed segregation when tested with races 304, 710, and 730, indicating that resistance was controlled by two independent genes. Therefore, RHA 419 has a new gene imparting resistance to all known races of downy mildew.

Technical Abstract: Downy mildew (Plasmopara halstedii) of sunflower (Helianthus annuus) is a worldwide disease, with at least 15 races now reported. Up to the present, downy mildew has been controlled successfully by the fungicide Apron. However, new races have evolved which attack sunflower with only Apron fungicide applied, and new fungicides have only been partially effective in their control. Therefore, genetic resistance is a major objective of sunflower researchers worldwide. Resistance to downy mildew derived from the USDA inbred sunflower line RHA 419 was studied in F2 and testcross progenies from crosses with a susceptible line and with lines carrying known resistance genes. The cross with a susceptible line indicated that RHA 419 had one dominant gene imparting resistance to races 304 and 710. The progenies from crosses of RHA 419 with lines carrying Pl5, Pl6, Pl7, or Pl8 all showed segregation when tested with races 304, 710, and 730, indicating that resistance was controlled by two independent genes. Therefore, RHA 419 has a new gene imparting resistance to all known races of downy mildew.