Molecular characterization and genetic diversity studies of Indian soybean (Glycine max (L.) Merr.) cultivars using SSR markers.

BACKGROUND: The genetic base of soybean cultivars in India has been reported to be extremely narrow, due to repeated use of few selected and elite genotypes as parents in the breeding programmes. This ultimately led to the reduction of genetic variability among existing soybean cultivars and stagnation in crop yield. Thus in order to enhance production and productivity of soybean, broadening of genetic base and exploring untapped valuable genetic diversity has become quite indispensable. This could be successfully accomplished through molecular characterization of soybean genotypes using various DNA based markers. Hence, an attempt was made to study the molecular divergence and relatedness among 29 genotypes of soybean using SSR markers. METHODS AND RESULTS: A total of 35 SSR primers were deployed to study the genetic divergence among 29 genotypes of soybean. Among them, 14 primer pairs were found to be polymorphic producing a total of 34 polymorphic alleles; and the allele number for each locus ranged from two to four with an average of 2.43 alleles per primer pair. Polymorphic information content (PIC) values of SSRs ranged from 0.064 to 0.689 with an average of 0.331. The dendrogram constructed based on dissimilarity indices clustered the 29 genotypes into two major groups and four sub-groups. Similarly, principal coordinate analysis grouped the genotypes into four major groups that exactly corresponded to the clustering of genotypes among four sub-groups of dendrogram. Besides, the study has reported eight unique and two rare alleles that could be potentially utilized for genetic purity analysis and cultivar identification in soybean. CONCLUSION: In the present investigation, two major clusters were reported and grouping of large number of genotypes in each cluster indicated high degree of genetic resemblance and narrow genetic base among the genotypes used in the study. With respect to the primers used in the study, the values of PIC and other related parameters revealed that the selected SSR markers are moderately informative and could be potentially utilized for diversity analysis of soybean. The clustering pattern of dendrogram constructed based on SSR loci profile displayed good agreement with the cultivar's pedigree information. High level of genetic similarity observed among the genotypes from the present study necessitates the inclusion of wild relatives, land races and traditional cultivars in future soybean breeding programmes to widen the crop gene pool. Thus, hybridization among diverse gene pool could result in more heterotic combinations ultimately enhancing genetic gain, crop yield and resistance to various stress factors.

An Economic Analysis of Pigeonpea Seed Production Technology and Its Adoption Behavior: Indian Context.

The present study was based on primary data collected from 100 farmers in Gulbarga district of Karnataka, India, during the agricultural year 2013-2014. Study shows that average land holding size of pigeonpea seed farmers was higher in comparison to grain farmers and district average. The study illustrates a ratio of 32 : 68 towards fixed and variable costs in pigeonpea certified seed production with a total cost of ₹ 39436 and the gross and net returns were ₹ 73300 and ₹ 33864 per hectare, respectively. The total cost of cultivation, gross return, and net return in pigeonpea seed production were higher by around 23, 32, and 44 percent than grain production, respectively. Hence, production of certified seed has resulted in a win-win situation for the farmers with higher yield and increased returns. The decision of the farmer on adoption of seed production technology was positively influenced by his education, age, land holding, irrigated land, number of crops grown, and extension contacts while family size was influencing negatively. Higher yield and profitability associated with seed production can be effectively popularized among farmers, resulting in increased certified seed production.

Interference of Nanoparticulates in seed invigoration of Green gram.

In the present study, the impact of four metal/metal oxide nanoparticles (NPs) viz.Ag, ZnO),ZVI and TiO2 on physiological seed quality attributes of green gram (Vigna radiata) were evaluated. The synthesized NPs characterized and evaluated the germination percentage, vigour indices and physiological responses like catalase and peroxidase activities (seed quality parameters) of fresh, naturally aged and fresh accelerated aged seed lots of green gram. In naturally aged seeds, zinc oxide-NPs (1000 mg kg-1) treated seeds showed 14.96% higher germination percentage, 24.81% higher vigour index I and (3696) and 33.33% higher vigour index II than the controls. The treated seeds with ZnO-NPs (1000 mg kg-1) under fresh accelerated aged conditions resulted in higher than 15.15% of germination percentage, 23.61% of vigour index I and 24.11% of vigour index II over controls. Moreover, ZnO-NPs treated naturally aged seeds showed lower electrical conductivity (EC) of 20.10 µ S cm-1g-1 than the control (26.60 µ S cm-1 g-1). Pertinent to catalase enzyme activity, ZnO-NPs (1000 mg kg-1) treated naturally aged seed lots resulted in 356.89 µmol H2O2 mg-1 min-1 activity, 216.05 µmol H2O2 mg-1 min-1 activity in fresh accelerated aged seed lots.. Similarly, ZnO-NPs (1000 mg kg-1) enhanced peroxidase enzyme activity in naturally aged seed lots (3.21 µg/FW/10 min) than control (0.72 µg/FW/10 min) that depicts 63.35% of increased enzyme activity. The present results showcases the ZnO-NPs as potent nano-priming agents in maintaining the seed quality parameters that ultimately establish better crop stand and field performance.

Delineation of Inheritance Pattern of Aleurone Layer Colour Through Chemical Tests in Rice.

BACKGROUND: Rice aleurone layer develops different colours with various chemical tests that may help to develop some rapid tests for identification/grouping of rice varieties. Understanding the colour inheritance pattern could enable to develop chemical clues that may help for genetic purity analysis along with grow-out-test. RESULTS: In this study, inheritance pattern of aleurone layer colour was studied in parents, F1 and F2 progenies derived from the crosses IR 36 × Acc. No. 2693 and IR 64 × Acc. No. 2693. The parent IR 36 showed light yellow (NaOH/KOH) and brown (phenol/modified phenol test) colour; whereas, Acc. No. 2693 revealed wine red/dark wine red (NaOH/KOH) and light brown colour/no reaction (phenol/modified phenol test). In contrary, another parent IR 64 exhibited light yellow (KOH/NaOH) and dark brown (phenol, modified phenol) colour. Both the F1 showed an intermediate light wine red colour (NaOH/KOH) and dark brown (phenol and modified phenol) colour, which is dominant over their one of the parents. The colour pattern with standard phenol/modified phenol, NaOH and KOH tests in F2 progenies of both the crosses showed 9:7 (complementary gene interaction) and 11:5 ratios (reciprocal dominance modification of recessive alleles), respectively. CONCLUSIONS: Our findings clearly elucidate the colour inheritance pattern in rice that may facilitate to develop rapid chemical tests to identify/ group the varieties for genetic purity analysis.