Behzad Sorkhilalehloo

Background Maintaining genetic diversity is of the most essential principle for a long-term conservation of plant genetic resources and could play a crucial role in their management. The genus Aegilops is one important member of wheat germplasm, and there are evidences that novel genes of this genus’ species can be studied/utilized as ideal sources for the wheat cultivar improvement. The objective of this study was to dissect the genetic diversity and population structure among a set of Iranian Aegilops using two gene-based molecular markers. Methods and results This study investigated the level of genetic diversity among 157 Aegilops accessions consisting of Ae. tauschii Coss. (DD genome), Ae. crassa Boiss. (DDMM genome), and Ae. cylindrica Host. (CCDD genome) belonging to NPGBI using two sets of CBDP and SCoT markers. The SCoT and CBDP primers yielded 171 and 174 fragments, out of which 145 (90.23%) and 167 (97.66%) fragments were polymorphic, respectively. The average of polymorphism information content (PIC)/ marker index (MI)/resolving power (Rp) for SCoT and CBDP markers were 0.32/3.59/16.03 and 0.29/3.01/16.26, respectively. Results of AMOVA revealed the genetic variability within species was greater than the variation observed among them (SCoT: 88% vs. 12%; CBDP: 72% vs. 28%; SCoT + CBDP: 80% vs. 20%). Based on the information obtained from both markers, the higher level of genetic diversity was found in Ae. tauschii as compared to other species. The grouping patterns obtained by Neighbor-joining algorithms, principal coordinate analysis (PCoA), and Bayesian-model-based structure were consistent with each other and resulted in grouping all studied accessions according to their genomic constitutions. Conclusion The results of this study revealed a high level of genetic diversity among Iranian Aegilops germplasm. Moreover, SCoT and CBDP marker systems were efficient in deciphering DNA polymorphism and classification of Aegilops germplasm.

Sorghum (Sorghum bicolor (L.) Moench) is the fifth important cereal considered a drought-tolerant crop. However, its reduction of grain yield considerably occurs in a shortage of water. In the current study, 10 sorghum genotypes were assessed for their grain yield under normal irrigation and water deficit irrigation. As well, the efficacy of several drought indices was evaluated for the selection of high-yield and drought-tolerant genotypes. The experiment was conducted as a split-plot considering three irrigation levels as main-plot and 10 genotypes as sub-plot. Correlation among the indices, clustering of the genotypes along with principal component analysis was employed. Yield production was significantly and positively correlated with indices MP (mean productivity), STI (stress tolerance index), GMP (geometric productivity), HM (harmonic mean), and YI (yield index) in all the irrigation levels. Therefore, these indices are more effective in the selection of high-yielding genotypes under different water conditions. Rank means of stress indices for each genotype revealed that genotype TN-04-79 in mild deficit irrigation and genotypes KGS23 and TN-04-79 in severe deficit irrigation were the most tolerant.