Loose smut resistant lines in wheat and triticale with combined resistance to Karnal bunt, rusts, powdery mildew and leaf blight

摘要

Loose smut caused by Ustilago segetum (Pres.) Russel var. tritici (Jensen) is one of the major diseases of wheat in northern India and is responsible for about 1-5 % yield losses every year, on an average (Joshi et al. 1988). The disease is totally seedborn and can easily be controlled by seed treatment with systemic fungicides like carboxin, carbendazim and tebuconazole (Chatrath et al. 1969; Bahadur and Sinha 1978; Sinha and Singh 1996). However, chemical usage has its own drawbacks and till date the adoption of these fungicides by the farmers is not up to the desired level, mainly due to the high cost of fungicides coupled with other issues like non availability of fungicides at proper time, unsuitable packing quantity and above all unfitness oftreated left over seeds for consumption. The issues of health and environmental hazards are also drawing attention and pressing for restricted uses of pesticides in agriculture. Keeping these problems in view, efforts were made by some workers in past toidentify resistant lines for loose smut (Aujla et al. 1990; Srivastava et al. 1992; Beniwal et al. 1998). However, such lines were not utilized extensively by the breeders since resistance to loose smut alone does not carry much significance in wheat since resistance to diseases like rusts and leaf blight is on the first priority of the wheat breeders. The present study was, therefore, done with an object to evaluate the wheat and triticale lines possessing resistance to other major diseases like rusts, Karnal bunt, powdery mildew and leaf blight, against loose smut, under artificially inoculated conditions so as to identify resistant sources that carry resistance to loose smut along with resistance to other important diseases.