Development and release of gamma ray induced sesame mutant ANK-S2 in Sri Lanka

Abstract

Epiphytotic conditions and non-availability of resistant germ plasm prompted the use of mutation induction technique to develop a variety resistant to phytophthora blight caused by Phytophthora nicotianae var. parasitica in sesame (Sesamum indicum L.). Dry seeds of three varieties were irradiated with six doses o f60Co gamma rays in the range 100-700 Gy. The mutant line 182/3 of variety MI 3 selected from 200 Gy dose treatment in the M2 showed tolerance to the disease at Angunakolapelessa in the disease nursery. The mutant line was tested in the advanced yield trial, National Co-ordinated Varietal Trials and in the National Coordinated Varietal Adaptability Trials. It was superior to MI 3 in yield and plant survival during the seasons favouring development of the disease and was similar to MI 3 and other recommended varieties during the other seasons. The variety has cream coloured seeds, branched stem, and recorded 1890 kg ha'1 at Girandurukotte, 1593 kg h a 1 at Maha Illuppallama and 1151 kg ha’1 at Angunakolapelessa under rainfed conditions. The mutant was released as ANK S2 in 1993 and may be used to increase the declining sesame area due to low yield of existing varieties and their susceptibility to disease. It should also serve as valuable parent material in cross-breeding programmes.