Drought stress limits crop production in the world. Therefore, employing high-yielding cultivars tolerant to drought is an effective approach to reduce its detrimental effects. To identify drought tolerant genotypes, 36 wheat genotypes were evaluated during the 2010-2011 and 2011-2012 growth seasons. A field experiment was conducted in a split plot design with two irrigation treatments (100% field capacity until harvest and no irrigation after anthesis) as main plots in three replications and genotypes as subplots. Grain yield, its components and drought tolerance indices were measured. Results showed a significant reduction in yield and its components under drought conditions. Grain yield had significant positive correlations with stress tolerance index (STI), mean productivity index (MP) and geometric mean productivity (GMP) while it was negatively correlated with stress susceptibility index (SSI) and tolerance index (TOL) under stress condition. These results indicated that superior genotypes could be selected based on high values of STI, MP and A c c e p t e d M a n u s c r i p t Downloaded by [University of Arizona] at 04:19 05 July 2014 GMP and low value of SSI. The results were validated by principal component analysis (PCA) as it showed genotypes with high PC1 and low PC2 were more desirable. Based on the results, genotypes number 8, 11, 17, 30, 34 and 35 were recognized as suitable for both conditions.

Leaf rust, caused by Puccinia triticina Eriks., is the most common rust disease of wheat (Triticum aestivum L.) worldwide. Owing to the rapid evolution of virulent pathotypes, new and effective leaf rust resistance sources must be found. Aegilops tauschii, an excellent source of resistance genes to a wide range of diseases and pests, may provide novel routes for resistance to this disease. In this study, we aimed to elucidate the transcriptome of leaf rust resistance in two contrasting resistant and susceptible Ae. tauschii accessions using RNA-sequencing. Gene ontology, analysis of pathway enrichment and transcription factors provided an apprehensible review of differentially expressed genes and highlighted biological mechanisms behind the Aegilops–P. triticina interaction. The results showed the resistant accession could uniquely recognize pathogen invasion and respond precisely via reducing galactosyltransferase and overexpressing chromatin remodeling, signaling pathways, cellular homeostasis regulation, alkaloid biosynthesis pathway and alpha-linolenic acid metabolism. However, the suppression of photosynthetic pathway and external stimulus responses were observed upon rust infection in the susceptible genotype. In particular, this first report of comparative transcriptome analysis offers an insight into the strength and weakness of Aegilops against leaf rust and exhibits a pipeline for future wheat breeding programs.

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Salinity problem with its vast spread on the earth is one of the main factors which limits crop production. One of the methods to overcome this problem is taking advantage of the resistant genotypes. Investigation of changes resulting from the stress in an electrophoretic profile of proteins and understanding its relation with the tolerance and susceptibility of cultivars is an important criterion for identifying such cultivars. In this study, 4 wheat cultivars with different degrees of tolerance were grown in hydroponic culture under salinity treatment (0, 70, 140 and 210 mM NaCl). Leaf sampling was done on 5 leaf stage. Studying the electrophoretic pattern of the leaf soluble proteins in salinity and control treatments showed fundamental similarities among the cultivars. No polypeptide bands belonging to the specific cultivars or to one of the salinity treatments were observed. The study of protein changes by electrophoretic analysis under salinity treatment may be useful for understanding the salinity tolerance of genotypes.