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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 #92119
Title: EVALUATING SUNFLOWER GERMPLASM FOR RESISTANCE TO PHOMOPSIS STEM CANKER

Author
item Gulya Jr, Thomas

Submitted to: Proceedings Sunflower Research Workshop
Publication Type: Proceedings
Publication Acceptance Date: 1/30/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: Phomopsis is a fungus that infects the leaves of sunflower and then progresses to produces a stem infection which often results in rotting of the stem and eventual lodging, with a great loss in yield. While the disease has been serious in Europe for over a decade, it has only become widespread and of economic importance in the United States within the last 4-5 years, when the weather pattern shifted from hot, dry summers to wet summers. During the last two years, we have conducted field tests of commercial hybrids (comparing the best European hybrids with U.S. entries), USDA breeding material and Plant Introductions, and done studies to determine the inheritance of resistance. In both years, European hybrids have been the most resistant, but in 1997 several U.S. experimental hybrids rivaled the best European entries. These trials have also identified many releases USDA lines with high levels of resistance to Phomopsis, which could be used by seed companies to produce resistant hybrids.

Technical Abstract: Phomopsis stem canker has increased in both incidence and severity to where it is the second most damaging disease of sunflower in the Dakotas and Minnesota (behind Sclerotinia wilt/stalk rot). Since the disease has only become economically important in the last five years, very few hybrids are available which combine high yield and resistance to Phomopsis. This study is the second year of a multi-faceted test to evaluate a broad range of germplasm for resistance to Phomopsis stem canker. The field test used natural infection to evaluate (1) US and European hybrids, (2) USDA Plant Introductions, (3) USDA released inbreds and interspecific germplasm, (4) U.S. commercial hybrids and a number of foreign hybrids in the FAO-sponsored trial. Sources displaying near total resistance to Phomopsis, even at physiological maturity, were identified in all groups of germplasm examined. European hybrids were the most resistant, but some U.S. experimental hybrids were equal to the best European hybrids. Several interspecific lines had excellent resistance to Phomopsis, and this may represent new genes.