ABSTRACT
Mung bean [Vigna radiata (L.) Wilczek] is an important grain legume crop. Earlier works on micropropagation protocols for mung bean suffer from genotype dependence, poor reproducibility and insufficient regeneration efficiency. Hence, we made an attempt to develop an efficient protocol for micropropagation of mung bean cv. KM 2 using transverse thin cell layer (tTCL) system. The epicotyl, hypocotyl and nodal tTCL explants were obtained from 5-day-old seedlings and cultured on MS medium with different concentrations of BAP (6-benzylaminopurine), TDZ (Thidiazuron) and kinetin. The maximum frequency (75.25%) of direct shoot initiation and multiplication was achieved from culturing the nodal tTCL explants on MS medium containing 1.0 mg/L BAP. It has been observed that 61.4% of the regenerated shoots successfully elongated and rooted in MS medium containing 1.0 mg/L of IBA (indole-3-butyric acid) after two weeks of culture. The plantlets successfully established under greenhouse conditions with 64 % survival rate. The hardened plants exhibited homogeneity and no morphological variations were detected among the regenerants and the mother plants. The identified regeneration system could be efficiently used in various in vitro manipulation studies in mung bean as well.
ABSTRACT
Sesame (Sesamum indicum L.) is an important crop known for its high-quality edible oil. Molecular markers are useful to explore highly diverse genotypes and relationships among populations for crossbreeding programs. In the present investigation, the genetic fidelity of 9 sesame cultivars of Tamil Nadu was assessed by 10 RAPD (Random Amplified Polymorphic DNA) and SSR (Simple Sequence Repeats) markers. A total of 102 DNA bands were obtained with RAPD primers, of which 46 were polymorphic. SSR primers generated 19 bands, of which 8 were polymorphic. The genetic relationships of nine varieties were inferred using the average linkage method. The cultivars were grouped into 2 clusters from RAPD and 3 clusters from SSR markers. Among the two RAPD clusters, cluster I comprised of TMV 4, TMV 5, TMV 6, TMV 7, SVPR 1, VRI 1, VRI 2, and CO 1 and cluster II comprised of TMV 3 cultivar. In SSR clusters, cluster I consisted of CO 1 and VRI 2, cluster II consisted of TMV 5, TMV 6, TMV 7, VRI 1, and SVPR 1 and cluster III consisted of TMV 3 and TMV 4 cultivars. The experimental results showed that mono-geographical separation of cultivars generally did not result in the greater genetic distance. This study demonstrated that RAPD and SSR markers were appropriate for evaluation of low diversified sesame varieties. Understanding of these characteristics of sesame cultivars in Tamil Nadu will provide a theoretical foundation for further development of variation among the sesame cultivars.