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Showing 2 results for Shirzadian-Khorramabad
Improvement of Salinity Tolerance Indices and regulation of Na+ and K+ homeostasis in Hashemi Rice Mutants (Oryza sativa L.)

Volume 0, Issue 0 (ARTICLES IN PRESS 2024)
Abstract
Salt stress is a serious environmental threat reducing crop yield. Hence, developing any breeding plan requires an understanding of the basic physiology and cell molecular genetic regulation under salinity stress. In this study, we evaluated the effectiveness of gene expression changes on ion homeostasis comprising salt overly sensitive (SOS1) and vacuolar Na+/H+ antiporter (NHX1) along with ion content measurement and proline content in the rice mutants at Rice Research Institute of Iran in 2018-2019. To survey these realities, tolerant mutant genotypes (em4hs290 and em4hs84) along with Hashemi parent cultivar, IR28 (sensitive), and FL478 (tolerant) seedlings were treated with 100 mM NaCl. Based on the results of growth indices, the seedling length of Hashemi cultivar and IR28 decreased considerably about 44.7%, and 44.2% reduction to that of the control, and the leaves progressively yellowed. Results showed that proline content and K+ and K+/Na+ ratio increased about ~2–3-fold higher in the tolerant genotypes than in the susceptible ones. Also, the overall amount of the OsNHX1 and SOS1 expression increased in tolerant genotypes compared to the susceptible ones. Accordingly, the compatible solute accumulation significantly advanced resulting in improvement of ionic homeostasis and probably suppresses the stress. Moreover, the variable pattern of gene expression in the two salt-tolerant mutants (em4hs290 and em4hs84) and Hashemi parent showed that the induced mutation could increase the salt-tolerant in mutant genotypes through ionic and osmotic homeostasis. Generally, these tolerant mutant genotypes could be applied to develop salt-tolerant varieties in rice breeding programs which can bring on production sustainability.

 
Genetic Diversity and Population Structure in Hashemi Rice (Oryza sativa L.) Mutants Revealed by Morphological and Molecular Markers

Volume 26, Issue 3 (5-2024)
Abstract
Mutagenesis has been one of the effective methods for creating genetic diversity and plant mutants can be significant bio-resources for crop breeding and functional genomics studies. The genetic and phenotypic diversity of 95 selected mutants from 17 mutant populations, obtained from an EMS mutagenized rice Hashemi variety, were phenotypically and molecularly assessed in M3 generation. Phenotypic variation of these mutants showed that grain yield components varied among the selected mutants compared to the control plants. In parallel, genetic diversity assessed by 13 Inter-Simple Sequence Repeats )ISSR) primers showed that the number of amplified fragments per primer varied from 4 (pr1-7) to 11 (ISSR-7, ISSR-11). In general, 13 primers amplified 99 fragments, 50 of which were polymorphic (52.92%). The genetic variation created by ISSR markers within 17 populations varied from 11.11% in HM9 (Hashemi Mutant Line number 9) to 45.45% in HM2. The average molecular polymorphism value was 0.27. In the total genetic variance, 95% of differences were attributed to within-population diversity, and 5% were related to among-populations. The Unweighted Pair-Group Method with Arithmetic mean (UPGMA) trees illustrating ISSR diversity classified the rice mutant population into seven groups, which were further supported by model-based STRUCTURE analysis. In general, the studied mutant genotypes revealed desirable genetic characteristics in populations 13 and 17, with em3h204 and em3h280 genotypes being the most divergent. 
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