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ARS Home » Midwest Area » St. Paul, Minnesota » Plant Science Research » Research » Publications at this Location » Publication #167031
Title: RELATIONSHIP OF DISEASE RESISTANCE AND STAND PERSISTENCE IN ALFALFA CULTIVARS FROM THE 1940S TO THE 1990S

Author
item ARISS, J - OHIO STATE UNIVERSITY
item RHODES, L - OHIO STATE UNIVERSITY
item SULC, R - OHIO STATE UNIVERSITY
item Lamb, Joann

Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 8/15/2004
Publication Date: 8/15/2004
Citation: Ariss, J.J., Rhodes, L.H., Sulc, R.M., Lamb, J.F.S. 2004. Relationship of disease resistance and stand persistence in alfalfa cultivars from the 1940s to the 1990s [abstract]. Phytopathology. 94:S5.

Interpretive Summary:

Technical Abstract: Over the past six decades cultivated alfalfa has been bred to incorporate desirable agronomic traits, including improved yield, forage quality, and resistance to disease and insect pests. However, some studies have suggested that limited progress has been made in alfalfa yield and persistence, regardless of improvements in disease resistance. A 4-year field trial, seeded in 1999, compared yield, percent ground cover, and disease incidence and severity of several diseases among sixteen alfalfa cultivars. Entries were selected to include the top-yielding varieties by decade from the 1940s to the present. Additional modern cultivars were included as checks. In September 2003, percent ground cover was less in stands of cultivars with older release dates than stands of modern varieties. As expected, more plants affected by Fusarium wilt (Fusarium oxysporum f. sp. medicaginis) and anthracnose (Colletotrichum trifolii) were present in varieties with lower reported resistance. There were highly significant negative correlations between Fusarium wilt incidence and percent ground cover. Anthracnose incidence and percent ground cover also showed a significant negative correlation. There were no significant correlations between percent ground cover and spring black stem, summer black stem, Rhizoctonia stem blight or Sclerotinia crown and stem rot. While increased resistance to the major alfalfa diseases may not account wholly for increased yield and persistence, disease incidence data from Ohio suggests that resistance to specific diseases enhances stand persistence.