Latest Research on Wheat Genetics : Jun 2020

Chromosome 1B-encoded gliadins and glutenin subunits in durum wheat: Genetics and relationship to gluten strength

The progenies of crosses between Berillo and four durum wheat cultivars were analysed for storage protein composition (by four different electrophoresis procedures), genetic segregation and gluten quality (by SDS sedimentation test and Viscoelastograph). The crosses enabled the segregation patterns of alleles at Gli-B1, Glu-B3 and Glu-B1 on chromosome 1B, and at Gli-A2 on chromosome 6A to be determined. The gene order on chromosome 1B was deduced to be Glu-B1-centromere-Glu-B3-Gli-B1, with 47% recombination between Glu-B1 and Glu-B3, and 2% between Glu-B3 and Gli-B1. Genes coding for γ-gliadins at Gli-B1 were distal to ω-gliadin genes with respect to the centromere. Analyses of the prog progeny (F4 grains) from single F2 plants, indicated that gliadins γ-42 and γ-45 are only genetic markers of quality, whereas allelic variation for low molecular weight (LMW) glutenin subunits encoded at the Glu-B3 locus is primarily responsible for differences in SDS sedimentation volume and gluten viscoelastic properties.  [1]

Single-kernel analysis of glutenin: use in wheat genetics and breeding

Glutenin was quantitatively extracted from single kernels of (i) the hexaploid Chinese Spring and all except five of the compensating nullisomic-tetrasomic stocks, (ii) nullisomic-trisomic lines of 2A-2B, 7D-7A and 7D-7B, (iii) 31 ditelocentric lines in which both of a pair of chromosomes lacked one arm, (iv) the hexaploids Prelude, Canthatch, Thatcher and Rescue, and their derived tetraploid strains, (v) the Cheyenne-Chinese Spring substitution lines, (vi) 80 hexaploid varieties from the USDA World Wheat Collection, (vii) 55 tetraploid wheats, most of which were Triticum durum, but with some wild emmer wheats were included, (viii) nine diploid wheats of T. monococcum, T. aegilopoides and T. boeticum, and (ix) Aegilops squarrosa var. strangulata. In addition, various common and durum varieties were examined. Glutenin subunit composition was determined by sodium dodecyl sulphate polyacrylamide gel electrophoresis. [2]

Wheat Genetics Resource Center: The First 25 Years

The Wheat Genetics Resource Center, a pioneering center without walls, has served the wheat genetics community for 25 years. The Wheat Genetics Resource Center (WGRC) assembled a working collection of over 11,000 wild wheat relatives and cytogenetic stocks for conservation and use in wheat genome analysis and crop improvement. Over 30,000 samples from the WGRC collection of wheat wild relatives, cytogenetic stocks, and improved germplasm have been distributed to scientists in 45 countries and 39 states in the United States. The WGRC and collaborators have developed standard karyotypes of 26 species of the Triticum/Aegilops complex, rye, and some perennial genera of the Triticeae. They have developed over 800 cytogenetic stocks including addition, substitution, and deletion lines. [3]

SSR- Based Genetic Diversity Assessment in Tetraploid and Hexaploid Wheat Populations

Molecular analysis for a set of hexaploid (Triticum aestvium) and tetraploid (Triticum durum) wheat cultivars was investigated by applying 11 SSR primers set. The plant materials consisted of 45 genotypes 15 of which were Triticum aestivum and 30 of T. durum obtained from four different regions Egypt, Greece, Cyprus and Italy. PCR products were separated on a 6% denaturing polyacrylamide gel electrophoresis and produced a total of 3840 DNA fragments which were used for the molecular analysis. The estimated parameters computed by POPGENE (Version 1.32) within the two population indicated that the Nei’s genetic diversity (H) was 0.2827, and the Shannon’s Information index (I) was 0.4533 with standard deviation ± 0.0699 and ± 0.0852 respectively. [4]

Genetic Analysis of Grain Yield and Its Components in Bread Wheat (Triticum aestivum L.)

Aims: Increasing yield is the most important aim in any breeding program. Since yield is a complex trait with low inheritance and involves several quantitative components, its direct study is not usually sufficient and therefore it is suggested that its components be investigated instead. Awareness of gene action of traits is very important in plant breeding methods.

Study Design: The experiment was conducted using a randomized complete block design with two replications for each generation.

Place and Duration of Study: P1, P2, F2, F3 and F4 generations of a Gaspard (sensitive) × Kharchia (tolerant) cross were used as genetic materials. The parents and F2, F3 and F4 populations were grown in 2010-2011 growing season in the research farm of international center for sciences, High Technology & Environmental Science-Kerman Iran. [5]

Reference

[1] Pogna, N.E., Autran, J.C., Mellini, F., Lafiandra, D. and Feillet, P., 1990. Chromosome 1B-encoded gliadins and glutenin subunits in durum wheat: genetics and relationship to gluten strength. Journal of Cereal Science, 11(1), pp.15-34.

[2] Bietz, J.A., Shepherd, K.W. and Wall, J.S., 1975. Single-kernel analysis of glutenin: use in wheat genetics and breeding.

[3] Gill, B.S., Friebe, B., Raupp, W.J., Wilson, D.L., Cox, T.S., Sears, R.G., Brown‐Guedira, G.L. and Fritz, A.K., 2006. Wheat genetics resource center: the first 25 years. Advances in Agronomy, 89, pp.73-136.

[4] Abouzied, H.M., Eldemery, S.M. and Abdellatif, K.F., 2013. SSR-based genetic diversity assessment in tetraploid and hexaploid wheat populations. Biotechnology Journal International, pp.390-404.

[5] Abbasi, S., Baghizadeh, A., Mohammadi-Nejad, G. and Nakhoda, B. (2014) “Genetic Analysis of Grain Yield and Its Components in Bread Wheat (Triticum aestivum L.)”, Annual Research & Review in Biology, 4(24), pp. 3636-3644. doi: 10.9734/ARRB/2014/7565.

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