Characterization of 60CO γ-ray induced pod trait of blackgram-A promising yield mutants.

Purpose: Blackgram (Vigna mungo (L.) Hepper) possesses natural flower dropping character with self-pollination, which was highly challenging to create variability through hybridization. Gamma irradiation is a powerful tool to induce genetic alteration and improvement in crops with beneficial mutants. Hence, the present investigation focused on finding out the mutant characters related to the improvement of the agronomic characters and yield-related traits by using gamma irradiation. Pod mutant isolated with fruitful agronomic trait at M2 (Mutagenic) generation was identified and isolated by gamma irradiation is a central focus in the present study, which enhances the yield of the blackgram.Materials and methods: Viable and uniform size of blackgram Vamban-4 seeds were irradiated at a different dose of 60CO (Cobalt) γ-rays viz., 200, 400, 600, 800, 1000, and 1200 Gray (Gy). The further generations were screened and raised to M3 and M4 plants to select the stable mutants with yield traits.Results: In the M2 generation, the following viable and pod mutants were identified, such as tall, dwarf, multipod, small pod, bold pod, striata pod. Morphological traits, such as plant height (PH), number of branches per plant (NBP), number of leaves per plant (NLP), number of cluster per plant (NCP), number of pods per plant (NPP), number of seeds per pod (NSP), pod length (PL), a hundred seed weight (HSW), seed yield per plant (SYP), were measured. Among the mutants, the increased morphogenetic traits were recorded in tall mutants (600 Gy), and the enhancement of yield characteristics noticed in multipod (800 Gy) and bold pod mutants (600 Gy). Compared to other doses, 600 Gy shows enhanced quantitative traits for blackgram improvement.Conclusion: The 60CO γ-rays induced genetic variation in the yield and its related traits and obtained pod mutants, which are useful to enhance the commercial value of Vigna species and crop improvement.

Heavy metal enrichment in the seagrasses of Lakshadweep group of islands--a multivariate statistical analysis.

An assessment on heavy metal (Al, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb and Zn) accumulation by seven seagrass species of Lakshadweep group of islands was carried out using multivariate statistical tools like principal component analysis (PCA) and cluster analysis (CA). Among all the metals, Mg and Al were determined in higher concentration in all the seagrasses, and their values varied with respect to different seagrass species. The concentration of the four toxic heavy metals (Cd, Pb, Zn and Cu) was found higher in all the seagrasses when compared with the background values of seagrasses from Flores Sea, Indonesia. The contamination factor of these four heavy metals ranged as Cd (1.97-12.5), Cu (0.73-4.40), Pb (2.3-8.89) and Zn (1.27-2.787). In general, the Pollution Load Index (PLI) calculated was found to be maximum for Halophila decipiens (58.2). Results revealed that Halophila decipiens is a strong accumulator of heavy metals, followed by Halodule uninervis and Halodule pinifolia, among all the tested seagrasses. Interestingly, the small-leaved seagrasses were found to be efficient in heavy metal accumulation than the large-leaved seagrass species. Thus, seagrasses can better be used for biomonitoring, and seagrasses can be used as the heavy metal sink as the biomass take usually long term to get remineralize in nature.