Gamma Ray-Induced Field Tolerance to Phytophthora Blight in Sesame |
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Authors: | R Pathirana |
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Institution: | Department of Agronomy, Faculty of Agriculture, University of Ruhuna, Kamburupitiya, Sri Lanka |
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Abstract: | Due to the non-availability of sources of resistance in Sri Lanka to Phytopbthora blight in sesame (Sesamum indicum) caused by Phytopbthora nicotianae var. parasitica, a mutation breeding programme was initiated. Seeds of three genotypes were subjected to six doses of gamma rays from 100 Gy to 750 Gy from a 60Co source. Seeds of M2 bulks, sampled by variety and treatment from the first five capsules formed on M1 plants, were grown in a field with a history of repeated incidence of the disease. The best 21 lines, having the highest survival and seed production, identified in the screening of M3 and M4 progeny rows of selected M2 single plants were then tested in a replicated field trial with the recommended cultivar ‘MI 3’ as a control. The plant survival in selected lines averaged 43.3 percent as against 7.2 percent in the recommended variety. Eight selections recorded significantly higher seed yield than ‘MI 3’ at P < 0.01 and another three at P < 0.05. Gamma ray treatments of 450 Gy and 600 Gy produced more lines tolerant to the disease than the other doses used. |
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Keywords: | Sesamum indicum Phytophthora nicotianae seed mutagenesis gamma irradiation performance disease field tolerance resistant line selections |
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