MSc

The study entitled ‘Genetic variability analysis in Indian indigo (Indigofera tinctoria L.) using Random Amplified Polymorphic DNA (RAPD) technique’ was carried out during 2003-2004 at Department of Plantation Crops and Spices and at the biotechnology lab of the Department of Plant Biotechnology, College of Agriculture, Vellayani.
Indigofera tinctoria is a valuable medicinal plant, which is also utilized as a natural source of the blue dye, ‘indigo’. Twenty accessions of Indigofera tinctoria collected from different parts of Kerala state were assessed for morphological and molecular variability. The significant difference among the genotypes for different traits such as plant height, plant spread, height at first branching, number of branches, girth of stem, length and breadth of leaves, number of leaves, leaf area, root length, root girth at collar region, fresh and dry weight of leaves, shoots, pods, seeds, number of root nodules, number of effective root nodules, root fresh weight together with fresh and dry weight of root nodules and shell weight revealed considerable amount of genetic variability. The highest phenotypic and genotypic coefficient of variation was recorded for number of effective root nodule followed by pod yield and shoot yield. Correlation studies revealed that at both phenotypic and genotypic levels the characters such as number of branches per plant, number of leaves per plant and leaf area were positively correlated with leaf yield, shoot yield, root yield and pod yield. Root length had high positive correlation with root yield. Selection index was worked out and it was found that the accession IT 13 was found to be superior, followed by the accessions IT 11 and IT 9.
All the twenty accessions of Indigofera tinctoria from different parts of Kerala state were used for RAPD profiling. Random Amplified DNA (RAPD) profiling of all accessions was done using polymerase chain reaction using OPA and OPB primer kits (each primer kit contain different primer sequences). After initial screening, the primers OPA 10, OPB 3, OPB 5 and OPB10 were selected for further analysis. The selection was based on the reproducibility of the bands, level of polymorphism, number and intensity of bands produced. These four primers produced a total of 26 RAPDs (average 6.5 bands per primer) of which 17 were polymorphic (65.38 %) and 7 were monomorphic (34.62 %). Similarity and variation among these accessions were observed by cluster analysis with the help of dendrogram. A similarity matrix was constructed and the similarity coefficients ranged from 0.46 to 1.0. The molecular variability analysis of twenty accessions of Indigofera tinctoria revealed that the accession IT 13 was found to be distinct from all the other accessions with respect to the polymorphic banding pattern.
The study, thus indicated morphologically distinct, superior lines were also genetically differentiable.