The 2009 ASHS Annual Conference

Horseradish (Armoracia rusticana Gaertn., Mey. & Sherb.) is a major horticultural crop grown in the St. Louis metro east area in Illinois.  It is asexually propagated from root cuttings, called sets, that are saved from the previous years crop.  All cultivars used by Illinois growers result from a breeding program that was initiated about 50 years ago in the state.  The objective of this research was to evaluate 23 horseradish cultivars over the 2006 to 2008 growing seasons at grower locations in the Caseyville/Collinsville, Ill. area for yield, set production, root quality and resistance to internal root discoloration (IRD).  Horseradish cultivars that provided high primary root yields included 405, 406, 1573, 1590, D25E2 and ‘German,’ while those with high set production (> 4 sets per plant) were 15K, 1573, and D25E2.  Horseradish cultivar root quality as well as the incidence and severity of IRD were inconsistent over the three growing seasons.  Those cultivars that generally provided high root quality characters (e.g., smooth, non-hairy roots) were 405, 15K, 1573, 1038, D25E2, and ‘German.’  Internal root discoloration is a soil-borne disease complex that is currently the biggest challenge facing the Illinois horseradish industry.  Horseradish cultivars with low incidence of IRD included 15K, 402, 405, and 22C, while those with low severity of IRD were 330, 405, 7586, 9705, 15K, and 22C.  These results indicated that the horseradish cultivars 405 and 15K consistently provided high quality characters, IRD tolerance and yield.