DUS Testing of Sesame (Sesamum indicum L.) Accessions Using Morphological Descriptors and Evaluation for Foliar Diseases of Sesame

The aim of the present study is to characterize Seven hundred and twenty accessions of Sesame (Sesamum indicum L.) along with two National check varieties viz., GT-10, TKG-22 and local check variety DS-5 were characterized based on the DUS descriptors. The experiment was executed in Augmented Block Design without replication at All India Co-ordinated Research Project on Sesame and Network on Niger experimental plot, Main Agricultural Research Station, University of Agricultural Sciences, Dharwad, Karnataka during kharif 2016. On the basis of DUS descriptors, Sesame accessions were characterized for twenty morphological descriptors and grouped into five DUS traits, viz. Growth, Stem, Leaf, Inflorescence and Capsule characters and evaluated for foliar diseases. A significant amount of variation was observed for most of the traits studied. Study of growth traits clearly revealed that majority of the genotypes showed variability for growth habit towards semi-erect types with determinate growth types and sparse hairiness on stem with majority of basal branching pattern. Towards stem characters, higher frequency of sparse/weak hairiness, lanceolate leaf shape for middle leaves, linear leaf shape for top leaves, entire basal leaf margin, absence of lobe incision of basal leaf and green petiole colour for leaf characters was observed in the studied set, respectively. Regarding inflorescence descriptors, 86.7 % of accessions exhibited one flower/leaf axil. Flower interior and exterior colour 38-39 % respectively. Sparse type corolla hairiness was in majority. Similarly, four number of locules/capsule, narrow oblong bicarpellate capsule shape, monocapsular arrangement, glaborous type of capsule hairiness for capsule characters also in higher frequency. 26.3 per cent of tested accessions have recorded beige colour at post harvest stage. Among 720 accessions studied only 1.3 % of accessions rated grade 2 for bacterial leaf blight and 9.3 % of accessions scored grade 3 for Cercospora leaf spot indicating moderately resistant genotypes. The identified DUS traits will serve as a marker in selection process which are less influenced by environmental fluctuations and are easily scorable and stable expression. They serve as diagnostic descriptors of germplasm accessions and hence useful to avoid mistakes in labelling, aid identification and minimize duplication in the germplasm and helps in the development of guidelines for varietal release and registration of new varieties of sesame. The study revealed the distinct characteristics of sesame accessions for morphological variations that exist in these lines due to variation in genetic makeup and could be better utilized by breeders in the selection based on their specific requirement for breeding programme. This study is highly useful for varietal identification and conservation.