Revealing contrasting genetic variation and study of genetic diversity in urdbean (Vigna mungo (L.) Hepper) using SDS-PAGE of seed storage proteins

Total seed storage protein profiles of 20 urdbean genotypes including the popular variety T9 were analysed by Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). 14 genotypes could be clearly identified based on genotype-specific seed protein fingerprints while rest of the test genotypes were categorized into three protein types. Dendrogram based on electrophoretic data clustered the genotypes into seven groups at 78.5% phenon level.  TU 95-1 with TU 12-25-4 revealed lowest similarity index value (0.33) followed by TU 95-1 with PU 30 and KU 96-3(SI=0.35). Clustering pattern revealed distinctly divergent group formed by TPU 95-1 and TPU 4. These may serve as a valuable source genotype in recombination breeding.   Key words: Seed storage protein profiling, SDS-PAGE, Genetic variation, urdbean

Identification of seed storage protein markers for drought tolerance in mungbean

A set of 292 mungbean germplasm accessions including 62 popularly adapted local land races and two wild forms (Vigna radiata var. sublobata), important breeding lines and standard ruling varieties were screened for drought stress tolerance at seedling stage.  Eight genotypes e.g., C. No. 35, OUM 14-1, OUM 49-2, Pusa 9072, OM 99-3, Banapur local B, Nipania munga, Kalamunga 1-A) have been identified to possess drought tolerance.  Globulin seed storage protein profiling was carried out in 19 selected mungbean genotypes comprising eight drought tolerant, seven drought sensitive, two wild forms of mungbean (TCR 20 and TCR 213) and two standard checks (LGG 460 and T 2-1) to explore differentially expressed polypeptides. Seed protein profiles revealed 15 scorable polypeptide bands with molecular weights ranging from 10.0 to 102.2kD. A specific 12.8kD polypeptide band was present in all above drought tolerant test genotypes including the wild accession TCR 20. Such a polypeptide band may serve as useful biochemical marker for identification of drought tolerant genotypes in mungbean.             Key words: Genetic diversity, seed storage protein profile, wild and cultivated Vigna radiata

Assessment of the recurrent mutagenesis efficacy of sesame crosses followed by isolation and evaluation of promising genetic resources for use in future breeding programs

The primary causes of low sesame production are a lack of high-yielding varieties, an inability to adjust to environmental challenges, and a poor response to enhanced crop management. The potential for improving sesame has been investigated using a variety of breeding approaches, including mutation and recombination breeding; however, these methods have only produced a minor increase in productivity. Recombination and mutant breeding have recently been proposed as novel, cutting-edge approaches to overcome the limitations of conventional breeding practices. This study was conducted to assess the recurrent mutagenesis efficacy of sesame crosses, followed by the isolation and evaluation of superior breeding lines that could be released as varieties in the future. In the F4M4 generation, the populations were grown in a randomized block design (RBD), and the efficacy of recurrent mutagenesis was assessed in terms of variability parameters such as the mean, standard deviation, and coefficient of variation. During the F5M5 generation, the materials were grown in three separate trials in Compact Family Block Design to evaluate the between-family and within-family variations, followed by the isolation of improved breeding lines based on per se performance. The improved breeding lines were further advanced to the F6M6 generation for evaluation in three separate trials in an RBD. In the F6M6 generation, ANOVA, correlation, regression, path coefficient, and Mahalanobis’s D 2 analysis were computed, followed by the construction of selection indices to select superior lines. The results showed the importance of three or four EMS treatment cycles for sesame improvement in the F4M4 generation. Twenty of the top lines based on per se performance (with a selection intensity of 27%) from each category in the F5M5 generation were carried forward to the F6M6 generation. In the F6M6 generation, the top six breeding lines (with a selection intensity of 30%) from each category, for a total of 18 breeding lines, were chosen based on these index scores. These high-yielding micromutant lines could be subsequently released as varieties through multiplication trials with standard checks. After a thorough evaluation, these lines have the potential to replace the current varieties and increase production, productivity, and adoption of sesame in India