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ARS Home » Midwest Area » Madison, Wisconsin » U.S. Dairy Forage Research Center » Research » Publications at this Location » Publication #67081
Title: TEMPERATURE DEPENDENT REACTION AND SELECTION RESPONSE OF TWO RED CLOVER POPULATIONS TO FUSARIUM OXYSPORUM

Author
item VENUTO, BRADLEY - LSU, DEPT OF AGRONOMY
item Smith, Richard
item GRAU, CRAIG - UNIV OF WISCONSIN-MADISON

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/10/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: The soil-borne fungal pathogen, Fusarium oxysporum, infects the root and crown tissue of the forage legume red clover causing severe root and crown rot and reduces the stand-life of this perennial forage. Selection for genetic resistance against this pathogen in red clover would reduce the degree of root and crown rot and extend its stand-life. However, when selecting for genetic resistance we observed that the disease symptom expressions of different populations of red clover were inconsistent at different temperatures. This suggested that different genetic mechanisms were operative in the different populations of red clover. Thus, different breeding and selection strategies have to be employed in the different populations to develop red clover with genetic resistance to the disease.

Technical Abstract: Two populations of red clover (Trifolium pratense L.), C11 and Arlington, were inoculated with a single-conidium isolate of Fusarium oxysporum Schlect. and grown in controlled environment chambers at 16 and 28 deg C. Resistant phenotypes were selected from each population at each temperature and recombined to form advanced populations for subsequent cycles of evaluation and selection. Three cycles of selection demonstrated that response to the pathogen was consistently and significantly greater at 28 deg C for both populations. However, the two red clover populations responded differently to the temperature of the selection environment. There were significant population by selection temperature interactions for cycle 1 and cycle 2 plants. Given the genetic homogeneity of the pathogen, the difference in population response to selection temperature is probably due to the existence of distinct mechanisms of resistance in the host populations. These results have important implications for the development of durable red clover resistance to F. oxysporum.