A comparative karyo-morphometric analysis of Indian landraces of Sesamum indicum using EMA-giemsa and fluorochrome banding

Sesamum indicum commonly known as ‘Sesame’, ‘Til’ or ‘Gingli’ is an age-old high valued oil crop. With distinct seed and floral diversity and no detailed chromosomal analysis is available on Indian landraces of S. indicum (2n= 26). The present study demonstrates standardization of enzymatic maceration and air drying (EMA) method of chromosome preparation and comparative karyometric analysis in four Indian landraces of S indicum. All the landraces were characterized by very small chromosomes, length ranging from 1.24 ± 0.02 to 2.87 ± 0.09 µm. The EMA- Giemsa based karyotype analysis revealed nine pairs of chromosomes with nearly median primary constriction, three pairs were submedian and a single satellite pair in each of the studied landrace. The CMA staining of Sesamum chromosomes revealed the presence of distinct CMA positive (CMA+ve) signals in all the studied landraces. The Black seeded til (BT) and White seeded til (WT) were characterized by six chromosomes with distal CMA+ve signal on short arm, while the Dark brown seeded til (DBT) showed ten chromosomes with distal CMA+ve signal on short arm. The Light brown seeded til (LBT) was characterized by eight chromosomes with distal CMA+ve signal on short arm. The results obtained from the scatter plot of A1 versus A2 and PCA analysis provide a strong relationship with that of the fluorochrome banding analysis. The present research offers an explicit karyo-morphometric characterization of four Indian landraces of S. indicum for the first time.