ARS | Publication request: Variability associated with screening for common scab and verticillium wilt in potato

Submitted to: Potato Association of America Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: March 26, 2012
Publication Date: August 13, 2012
Citation: Braun, S., Uribe, P., Jansky, S.H. 2012. Variability associated with screening for common scab and verticillium wilt in potato [abstract]. Potato Association of America Proceedings. Paper No. 016.

Technical Abstract: Common Scab (CS) and Verticillium Wilt (VW) are caused by the soilborne bacteria Streptomyces scabies, and fungi, Verticillium dahliae and V. albo-atrum, respectively, in potato (Solanum tuberosum). Both diseases result in biological and/or marketable yield loss and are tested in fields with high disease pressure. Previous studies regarding VW have determined that sap from individual stems or bulked stems generate repeatable clone rankings and best explain the variability in yield loss. Studies that evaluate for CS typically assess the percent surface area (PSA, 1-100%) of the disease and lesion type (LT, 0-6) for individual tubers. However, unexplained variability has the potential to reduce detection of differences among genotypes and ultimately affect genotypic analysis for which continuous, phenotypic data is necessary. In this study, we have addressed variability associated with screening for CS and VW by determining the experimental unit size that reduces the standard deviation and limits the expense of testing per genotype. In 2011, eight check genotypes were planted in an RCBD, for a total of 14 plots each, in a field high CS pressure. Individual tubers were evaluated for both PSA and LT. In a separate field high in VW pressure, seven check genotypes were planted in an RCBD, for a total of three plots and four plants per plot from 2006 to 2011. These results will ultimately guide future decisions on number of tubers and plots to assess CS and the number of stems and plants to assess for VW.