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Selvakesavan R.K.,Institute of Forest Genetics and Tree Breeding | Dhanya N.N.,Institute of Forest Genetics and Tree Breeding | Dhanya N.N.,Nirmala College for Women | Thushara P.,Institute of Forest Genetics and Tree Breeding | And 21 more authors.
Symbiosis | Year: 2016

Casuarina equisetifolia Forst., a member of the Casuarinaceae family, is widely planted in coastal areas due to its ability to function as potential barrier against wind and waves. Significant variation has been reported in the ability of C. equisetifolia to grow under salinity stress. In the present study, 82 clones of C. equisetifolia were assessed for their response to 50 mM incremental NaCl concentrations ranging from 50 mM to 550 mM in Hoagland’s solution and clones with contrasted salt tolerance were identified. Several earlier reports attribute salt sensitivity in Casuarina species to the toxic effect of sodium. Intraclonal variation in the levels of sodium accumulation was therefore analysed. However, sodium content in the shoots and roots, showed little correlation (0.351 and −0.171) with salt tolerance in C. equisetifolia. Similarly, sodium to potassium ratio in the shoots and roots of NaCl treated and untreated clones also did not show correlation with mortality although certain tolerant clones exhibited selectivity of potassium over sodium under salt stress. Analysis of the shoot to root ratio of sodium however, showed better correlation (0.448) with salt tolerance, suggesting that restricted translocation of sodium to shoots and its relative retention in roots might play a crucial role in the salt tolerant clones of C. equisetifolia, and that shoot to root ratio of sodium could be a better parameter for salt tolerance in C. equisetifolia clones. The higher salt tolerance observed in certain clones despite higher sodium accumulation or shoot to root ratio of sodium suggests the presence of different multiple adaptive mechanisms that may be operating in different clones to help protect the cells from the toxic effects of sodium. The tolerant clone, TNIPT 4, which accumulated high concentrations of Na+, had low shoot to root ratio of Na+, and also a higher constitutive as well as NaCl induced accumulation of the compatible osmolyte, proline. The study thus emphasizes the need for characterising the genetic components involved in sodium transport, proline metabolism and other mechanisms contributing to salinity tolerance. The identified clones with contrasted stress tolerance mechanisms would thus be a valuable resource for transcriptomic, proteomic and metabolomic exploration in addition to their utility for field evaluation in flooded and coastal saline tracts. © 2016 Springer Science+Business Media Dordrecht

Ngom M.,Cheikh Anta Diop University | Ngom M.,Laboratoire Communications Of Microbiologie Ird Isra Ucad | Ngom M.,Laboratoire Mixte International Adaptation des Plantes et Microorganismes associes aux Stress Environnementaux LAPSE | Diagne N.,Laboratoire Mixte International Adaptation des Plantes et Microorganismes associes aux Stress Environnementaux LAPSE | And 7 more authors.
Symbiosis | Year: 2015

Frankia is a soil actinomycete that forms nitrogen-fixing root nodule symbioses with eight angiosperms families including Casuarinaceae. Knowledge on symbiotic performance of several isolated strains with Casuarina species is limited. In this study, we characterized a collection of Frankia strains based on their growth kinetics and their symbiotic ability with Casuarina glauca specie. Results showed that Frankia strains Allo2, CcI3, CeD and Cg70.9 do not exhibit the same symbiotic ability both for their infectivity and effectiveness towards Casuarina glauca. All strains were able to infect and improve C. glauca plants growth. Frankia isolate CcI3 better improved plants height while CeD and Cg70.9 strains formed more nodules on inoculated plants roots. However, there is no correlation between the number of nodules formed and the effectiveness of strains. These preliminary results give ideas on which Frankia strains to use for obtaining an efficient symbiosis with C. glauca. However, others plant species and growth conditions should be tested for a longer period to better optimize the use of Frankia in reforestation programs. © 2015 Springer Science+Business Media Dordrecht

Issa F.,Center National Of Recherches Agronomiques Cnra Isra | Issa F.,Cheikh Anta Diop University | Daniel F.,CIRAD - Agricultural Research for Development | Jean-Francois R.,CIRAD - Agricultural Research for Development | And 5 more authors.
African Journal of Biotechnology | Year: 2010

Production and seed quality in peanut (Arachis hypogaea L.) can be reduced substantially by in situ germination under unpredictable rainfed environments. Inheritance of fresh seed dormancy in Spanish x Spanish crosses was studied with two sets of segregating populations, an F2 population derived from true F1 hybrids identified with peanut microsatellites markers and other populations (F2, BC1P1S and BC1P2S) from randomly-selected F1 individuals. In the F2 population developed with true F1 hybrids, the chi square test was not significant for the deviation from the expected 3:1 (dormant: non-dormant) ratio. In addition, the bimodal frequency distribution curve with the F2 population gave more evidence that fresh seed dormancy is controlled by a single dominant gene. The average frequency (48%) of true F1 hybrids give evidence that deviations from expected ratios in the populations (F2 and BC1P1S) developed from non-tested F1 individuals, is most likely due to inadvertent selfs. This study emphasized the need to identify with molecular markers the cross progenies in self-pollinated crops as peanut before testing for any trait. © 2010 Academic Journals.

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