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Among the wild relatives of wheat, Triticum urartu Tumanian ex Gandilyan is of interest to wheat breeders. Numerous works have focussed on its utilization for enrichment of the genetic variation of cultivated genotypes. In the present study, the genetic diversity and population structure in 85 accessions of T. urartu were investigated using start codon targeted (SCoT) polymorphism and CAAT-box derived polymorphism (CBDP) markers. Nineteen SCoT primers and fifteen CBDP primers amplified 185 and 141 polymorphic fragments with an average of 9.74 and 9.40 fragments per primer, respectively. The polymorphic information content (PIC) for the SCoT and CBDP primers ranged from 0.41 to 0.50 and 0.40 to 0.49, with the resolving power (Rp) ranging from 21.61 to 3.97 and 13.08 to 28.02, respectively. Neighbour-joining (NJ) based clustering grouped 72 accessions into two main clusters based on the two sets of markers and the combined data. Genetic relationships inferred from STRUCTURE analysis was matched with cluster analysis and principal coordinate analysis (PCoA), indicating that the accessions were grouped into two major clades and the grouping patterns were not correlated with the geographic origins. The results from this study revealed that Iranian T. urartu, especially Kerend-e-Gharb and Sisakht-Pataveh populations, can be interesting for wheat improvement. Hence, conservation of this region is recommended.

The genes encoding 13 classes of pathogenesis-related (PR) proteins were examined for positive selection using maximum-likelihood (ML) models of codon substitution. The study involved 194 sequences from 54 species belonging to 37 genera. Although the sizes of the sequences examined varied from 237 bp for PR12 to 1,110 bp for PR7, most classes (9 out of 13) contained sequences made up of more than 400 nucleotides. Signs of positive selection were obtained for sites in PR proteins 4, 6, 8, 9 and 15 using an ML-based Bayesian method and likelihood ratio tests. These results confirm the importance of positive selection in proteins related to defense mechanisms already observed in a wide array of organisms.

The genetic variability of the Brazilian physic nut (Jatropha curcas) germplasm bank (117 accessions) was assessed using a combination of phenotypic and molecular data. The joint dissimilarity matrix showed moderate correlation with the original matrices of phenotypic and molecular data. However, the correlation between the phenotypic dissimilarity matrix and the genotypic dissimilarity matrix was low. This finding indicated that molecular markers (RAPD and SSR) did not adequately sample the genomic regions that were relevant for phenotypic differentiation of the accessions. The dissimilarity values of the joint dissimilarity matrix were used to measure phenotypic + molecular diversity. This diversity varied from 0 to 1.29 among the 117 accessions, with an average dissimilarity among genotypes of 0.51. Joint analysis of phenotypic and molecular diversity indicated that the genetic diversity of the physic nut germplasm was 156% and 64% higher than the diversity estimated from phenotypic and molecular data, respectively. These results show that Jatropha genetic variability in Brazil is not as limited as previously thought.