Submitted to: Mississippi Academy of Sciences Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: March 15, 2013
Publication Date: April 1, 2013
Citation: Miller Butler, M.A., Curry, K., Kreiser, B., Smith, B.J. 2013. Comparisons of electronic and visual ratings of strawberry leaves inoculated with two colletotrichum species. Mississippi Academy of Sciences Proceedings. 58:29-30. Technical Abstract: Inoculation of detached strawberry leaves with Colletotrichum species may provide a rapid and accurate method for identifying anthracnose resistant germplasm. The purpose of this study was to compare electronic and visual rating methods of screening for anthracnose resistance. Eight to 17 detached leaves of each of 21 strawberry clones (8 named "Cultivars" and 13 "MSUS" breeding clones) were inoculated with two Colletotrichum fragariae isolates and one C. gloeosporioides isolate. Anthracnose disease symptoms were analyzed quantitatively via computer based image analysis and qualitatively by two independent visual raters using a 0-5 rating scale (0=no disease, 5=lesion covering entire leaf). The "Cultivar" group had an average lesion area of 14% and an average disease score of 1.7 which were significantly higher than those of the "MSUS" group, which had an average lesion area of 6% and average disease score of 1.0. The higher values of the "Cultivar" group confirmed that as a group these clones were more susceptible to anthracnose than the "MSUS" group. A strong positive correlation was found between percent lesion area as determined by computer analysis and the visual disease scores of the two raters. Image analysis provided a precise measurement of percent lesion area of infected leaves while visual assessment provided rapid results.