Differential Responses of Sorghum Varieties to Picloram1
- C. J. Scifres and
- R. W. Bovey2
‘Pioneer 820’ seedlings were the most tolerant of seven sorghum (Sorghum bicolor (L.) Moench.) varieties to pre- or postemergence irrigation and to postemergence sprays with various concentrations of 4-amino-3,5,6-trichloropicolinic acid (picloram). Response to the herbiside varied widely among varieties. Significant increases in dry weight of Pioneer 820, ‘RS-625’, and ‘PAG-665’ occurred when treated preemergence with irrigation water containing 0.5, 1, and 2 ppm of picloram whereas ‘GA-615’, ‘RS-671’, ‘Tophand’, and ‘RS-626’ were reduced in growth by these concentrations. Dry weights of Pioneer 820 and RS-625 were increased by irrigation water containing .001 to .005 ppm of picloram applied postemergence or when treated with sprays containing 0.035 to 0.7 kg/ha. Tophand was the least tolerant of picloram regardless of method of application. Varieties intermediate in susceptibility to picloram such as GA-615, RS-671, and RS-626 tolerated the low concentrations used with the various treatment methods, but the higher concentrations often reduced seedling growth.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © . .