Inheritance and Assessment of Bentazon Herbicide Tolerance in `Santaka' Pepper

Experiments were developed to study the inheritance of the high level of tolerance to the herbicide bentazon exhibited by the pepper (Capsicum annuum L.) cultivar Santaka. Parental, F1, F2, and backcross populations of the cross 'Santaka' × 'Keystone Resistant Giant' were evaluated for injury in a greenhouse test using bentazon at a rate of 4.5 kg·ha -1 (1.1 kg×ha -1 is the rate recommended for most applications). Additionally, parental and F 1 populations were evaluated for injury under field conditions using sequential bentazon applications of 4.5, 4.5, 6.75, and 9.0 kg·ha -1 . A single, dominant gene determined tolerance. F1 hybrid plants (heterozygous at the locus conditioning tolerance) exhibited a high level of tolerance under field conditions. Results of the greenhouse test suggested a possible cytoplasmic involvement in the expression of the tolerance gene, but the results of the field test provided strong evidence that cytoplasm does not play a significant role. We propose that this gene be designated Bentazon tolerance and symbolized Bzt. Chemical name used: 3-(1-methylethyl)-(1H)-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide (ben- tazon). Bentazon is a selective postemergence herbicide used to con- trol certain broadleaf weeds and sedges in various major agro- nomic crops. Although highly toxic to many pepper cultivars and not currently registered for general use on the crop, ben- tazon is of interest to the pepper industry because it controls several broadleaf weeds and sedges (particularly yellow nut- sedge (Cyperus esculentus L.)) that cannot be controlled by currently registered herbicides. Additionally, most of the her- bicides presently used by pepper growers are applied preplant and there is a need for an effective herbicide to control emerged broadleaf weeds and sedges in the later growth stages of the