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EXPOSED TO MN STRESS Keywords: Barley; Genome Wide Association Analysis; Manganese; Morphological Traits; QTL EN Barley Genome Wide Association Analysis Manganese Morphological Traits QTL INTRODUCTION In agricultural systems, plant productivity is strongly influenced by environmental conditions. The objectives of this study were (1) to evaluate genomic regions affected Mn stress and contributive morphological traits in a diverse spring barley collection, (2) to establish marker-trait associations for each trait, and (3) to identify genes/loci affecting Mn stress in spring barley that can be used for genetic improvement in breeding programs. The manganese toxicity symptoms vary widely among plant species and varieties within species, perhaps because the phytotoxic mechanisms of Mn involve different biochemical pathways in different plant genotypes (El-Jaoual and Cox, 1998). [Extracted from the article]

Differentiation among populations of the Iranian Teucrium polium L. was analyzed on the basis of morphological and phytochemical variability, to evaluate the level and distribution of diversity among four distant populations from arid, semi-arid, and subhumid regions of Fars Province. Morphological analysis included 11 characters related to the plant, leaf, and stem morphology. Analyses of variances and clustering were done to establish the variability and significance of morphological differentiation. The morphological analysis of plants from the studied populations confirmed that the species belonged to malacophyllous xeromorphic species and were distinguished by stable conservative xeromorphic characteristics. Morphological variation was correlated with ecological conditions at the site of origin and there was a small difference between the plants belonging to arid and semi-arid populations and the sub-humid ones. Chemical analysis was performed using combination of capillary GC, GC-MS after fractionation on column chromatography. The chemical composition of their oil differed qualitatively and quantitatively between the populations. β-Caryophyllene was the major oil compound in the sub-humid and semi-arid populations, while the main compound of arid populations were farnesene-cis-b and linalool. In addition, oil samples from semi-arid and sub-humid populations contained β-bisabolene (1.6-2.2%), myrcene (0.9-1.1%), bornyl acetate (0.7- 0.8%), and 3-octanol (0.6-0.8%), which were not detected in oil samples from arid populations. All oil samples, however, were dominated by hydrocarbon compounds. The relatively low morpho-chemical diversity in the populations indicates that the maintenance of their evolutionary potential is at risk if population sizes are not maintained and if there is no protection of the habitats. [ABSTRACT FROM AUTHOR]