Performance of newly developed mutants of sesame (Sesamum indicum L.)

Three genotypes of sesame viz. TS3, Sanghar-1 and GP3804 were got irradiated with gamma rays ranging from 100Gy to 800Gy and were grown as M1 generation during kharif, 2003. The desirable mutants were selected from segregation population (M2) during 2004 and confirmed during 2005 in M3 generation. The selected true breeding lines were studied further for their different genetic behavior in respect of morphological/agronomic and economic traits. Based on this genetic information, six true breeding lines (NS11-2, NS11P2, NS100P2, NS103-1, NS240P1 and NS260) possessing higher seed yield along with disease resistance/tolerance and other desirable attributes were selected. These were evaluated for three consecutive years from 2006 to 2008, in station yield trials at Nuclear Institute for Agriculture and Biology, Faisalabad, Pakistan. The morphological attributes like days to flower, days to maturity, plant height, number of branches, capsule length, seeds per capsule, number of capsules, 100 seed weight, biomass yield, harvest index and seed yield were recorded. The data were subjected to analysis of variance and stability parameters for seed yield were computed. The results of combined analysis of variance showed highly significant differences among genotypes, environment and their interaction (genotypes x environment). It indicated that variation exists in the genotypes performance under different sets of environment during three consecutive years. Overall mean seed yield performance indicated that mutant line NS100P2, NS11-2 and NS103-1 produced higher seed yield (1871, 1547 and 1439 kg/ha) as compared to other mutant lines standard check TS3 and grand mean. NS100P2 had regression coefficient more than unity, hence is suitable for favourable environments to some extent. Similarly NS11-2 had also regression coefficient more than unity and standard deviations not near to zero. This mutant line had also poor wide adaptation. The mutant line NS103-1 proved as more stable because it produced higher mean seed yield along with regression coefficient near to unity and deviation to regression was almost near to zero. Morphological attributes of sesame mutants revealed that NS 260 showed an edge of earliness of three weeks (85 days) over the standard check TS3 (110 days). Further, this mutant line is resistant to lodging and withstands against heavy rains and wind storm. All mutant lines under study also showed more harvest index and more resistance to phyllody disease as compared to standard check TS3.