Differential Tolerance of Sugarcane Varieties to Herbicides¹

An experiment was conducted to find out the differential tolerance of sugarcane (Saccharum officinarum L.) varieties to pre-emergence application of atrazine (2-chloro-6-ethylamino-4-isopropylamino-l, 1, 3, 5-triazine) and diuron (3-(3, 4-dichloro-pheny) 1, 1-dimethylurea) each at 2.4 and 9.6 kg/ha. Sugarcane varieties screened were Co. 1158,00.281,00.449, Co. 527, Co. 658, Co. 1130, Co. 62174, Co. 1163, BO. 17, and Co. 997. The soil of the experimental field was sandy clay loam and of medium fertility. Data showed that there were highly significant differences in cane yield among the sugarcane varieties under different treatments. Diuron both at low and high doses significantly reduced the cane yields of varieties Co. 281, Co. 1340, Co. 62174, B. O. 17 and Co. 997 while the high dose reduced the yield of Co. 1158 and Co. 449. Likewise, the low and high doses of atrazine significantly reduced yield of varieties Co. 658, Co. 1340, Co. 62174 and Co. 997, while yield of variety Co. 1158 was affected only under high dose. Varieties Co. 527 and Co. 1163 were found tolerant to both atrazine and diuron while varieties Co. 281, Co. 449 and B. O. 17 were tolerant only to atrazine