Authors:J.Q. Xu, L. Wang, B.L. Liu, T.F. Xia, D.C. Liu, X. Chang, T.W. Zhang, H.G. Zhang, and Y.H. Shen
As one of the world’s earliest domesticated crops, barley is a model species for the study of evolution and domestication. Domestication is an evolutionary process whereby a population adapts, through selection; to new environments created by human cultivation. We describe the genome-scanning of molecular diversity to assess the evolution of barley in the Tibetan Plateau. We used 667 Diversity Arrays Technology (DArT) markers to genotype 185 barley landraces and wild barley accessions from the Tibetan Plateau. Genetic diversity in wild barley was greater than in landraces at both genome and chromosome levels, except for chromosome 3H. Landraces and wild barley accessions were clearly differentiated genetically, but a limited degree of introgression was still evident. Significant differences in diversity between barley subspecies at the chromosome level were observed for genes known to be related to physiological and phenotypical traits, disease resistance, abiotic stress tolerance, malting quality and agronomic traits. Selection on the genome of six-rowed naked barley has shown clear multiple targets related to both its specific end-use and the extreme environment in Tibet. Our data provide a platform to identify the genes and genetic mechanisms that underlie phenotypic changes, and provide lists of candidate domestication genes for modified breeding strategies.
Authors:A. Etminan, A. Pour-Aboughadareh, R. Mohammadi, A. Noori, and A. Ahmadi-Rad
Progress in plant molecular tools has been resulted in the development of gene-targeted and functional marker systems. CAAT box region is a different pattern of nucleotides with a consensus sequence, GGCCAATCT, which situated upstream of the start codon of eukaryote genes and plays an important role during transcription. In the present study, several CAAT box-derived polymorphism (CBDP) primers were used for fingerprinting in mini-core collection of durum wheat (including internationally developed breeding lines and Iranian landraces). Twelve selected primers amplified 98 loci, of which all were polymorphic. The average values of the polymorphism information content (PIC) and resolving power (Rp) were 0.31 and 9.16, respectively, indicating a high level of variability among studied genotypes. Analysis of molecular variance (AMOVA) indicated that 92% of the total variation resided among populations. The values of the percentage polymorphic bands (PPL), the observed (Na) and effective (Ne) number of alleles, Nei’s gene diversity (He) and Shannon’s information index (I) for Iranian landraces were higher than the breeding lines. The Fandendrogram obtained by cluster analysis grouped all individuals into three main clusters. Our results showed a remarkable level of genetic diversity among studied durum wheat, especially among Iranian landraces, which can be interest for future breeding programs. More importantly, the present study also revealed that CBDP technique was efficient and powerful tool to assess genetic diversity in wheat germplasm. Hence, this technique could be employed individually or in combination with other molecular markers to evaluate genetic diversity and relations among different species.
Authors:P. Martins-Lopes, B. Maças, and H. Guedes-Pinto
Guedes-Pinto, H., Pinto-Carnide, O., Igrejas, G., Nascimento, M., Carnide, V.P., Heslop-Harrison, J.S., Gateau, I., Branlard, G. 1998. Studies of Barbela wheat, an old Portuguese landrace with rye introgression. In: Lelley, T. (ed.), Current Topics in
Authors:Irma Tari, D. Camen, Giancarla Coradini, Jolán Csiszár, Erika Fediuc, Katalin Gémes, A. Lazar, E. Madosa, Sorina Mihacea, P. Poor, Simona Postelnicu, Mihaela Staicu, Ágnes Szepesi, G. Nedelea, and L. Erdei
Drought resistance of bean landraces was compared in order to select genotypes with either high morphological or high biochemical-physiological plasticity. The lines in the former group exhibited fast reduction in fresh and dry mass, decreased the water potential in primary leaves after irrigation withdrawal and the biomass mobilized from the senescent primary leaves was allocated into the roots. These genotypes had high frequency of primary leaf abscission under water stress. The genotypes with plasticity at the biochemical level maintained high water potential and photochemical efficiency, i.e. effective quantum yield, high photochemical (qP) and low non-hotochemical (NPQ) quenching in primary leaves under drought stress. While superoxide dismutase activity was not influenced by the drought and the genotype, catalase activity increased significantly in the primary leaves of the genotypes with efficient biochemical adaptation. Lines with high morphological plasticity exhibited higher quaiacol peroxidase activity under drought. Proline may accumulate in both cases, thus it may be a symptom of protein degradation or a successful osmotic adaptation. On the basis of contrasting responses, the genetic material cannot be screened for a large-scale breeding program by a single physiological parameter but by a set of the methods presented in this work.
.E., Ambrose, M.& Reader, S.M. (2001): The Watkins collection of land-race derived wheats. -in: Caligari, P.D.S. & Brandham, P.E. (Eds) Wheat Taxonomy: the Legacy of John Percival . The Linnean Special Issue, No. 3. Academic Press, pp. 113
Authors:Reshma, R. Agnihotri, R. Vamil, G. Singh, M. Ahmad, and R. Sharma
Agnihotri, R. K., Palni, L. M. S. and Pandey, D. K. (2006): Screening of landraces of rice under cultivation in Kumaun Himalaya for salinity stress during germination and early seedling growth. - Indian J. Plant