Submitted to: Weed Science Society of America Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/5/2004
Publication Date: 2/7/2005
Citation: Nordby, D.E., Williams, M.M, Pataky, J., Sprague, C. 2005. Association between the sensitivity of sweet corn to nicosulfuron and mesotrione [abstract]. Weed Science Society of America Meeting. Vol. 45:25.
Technical Abstract: Certain sweet corn(Zea mays L.) hybrids and inbreds can be injured by postemergence applications of nicosulfuron or mesotrione. An association between the sensitivity of sweet corn to these herbicides was observed in field trials in 2003 and 2004. In 2003, 288 sweet corn hybrids and 34 sweet corn inbreds were screened; and in 2004, 375 hybrids, 32 inbreds,and 64 S2 families were screened for reactions to nicosulfuron and mesotrione. Each experimental unit was a single 3.5m row with 12 to 18 plants. Herbicides were applied to half of each row when plants were at the 4- to 6-leaf stages. Nicosulfuron was applied at 34.7 g ai/ha with a 0.25% v/v nonionic surfactant and 2.5% v/v UAN. Mesotrione was applied at 105.3 g ai/ha with 1% v/v COC. Injury was rated visually (0 to 100%) 7 and 21 days after application. Hybrids and inbreds were classified as susceptible if injury was greater than 20%, moderate if injury was 5-20%, and tolerant if injury was less than 5%. S2 families were classified as susceptible, tolerant or segregating. In 2003, 63% (5 of 8) of the mesotrione-susceptible hybrids were susceptible to nicosulfuron compared with 6% (16 of 273) of the mesotrione-tolerant hybrids that were susceptible to nicosulfuron. In 2004, 3 of 6 mesotrione-susceptible hybrids were susceptible to nicosulfuron but none of 283 mesotrione-tolerant hybrids were susceptible to nicosulfuron. A similar association occurred among inbred lines. In 2003, 7 of 8 nicosulfuron-susceptible inbreds had some injury from mesotrione but none of the 26 nicosulfuron-tolerant inbreds were injured by mesotrione. In 2004, 7 of 9 nicosulfuron-susceptible inbreds were susceptible to mesotrione but only 1 of 19 nicosulfuron-susceptible inbreds was susceptible to mesotrione. The association between sensitivity to mesotrione and nicosulfuron also was evident among S2 families. Thirty families segregated for reactions to one of the herbicides. Of the 34 families with homogeneous reactions, 13 were mesotrione-susceptible and 11 were nicosulfuron-susceptible. Ten of 13 mesotrione-susceptible families were nicosulfuron-susceptible but only 1 of 21 mesotrione-tolerant families was susceptible to nicosulfuron. Further studies of families derived from selected sweet corn inbreds will examine the genetic basis for the similarity of these reactions.