Genetic diversity and breeding value of synthetic hexaploid wheat introduced into the VIR collection

For the  successful  development of wheat  breeding in Russia, a genetically  diverse  and  well-characterized starting material, mainly stored  at the VIR collection, is needed. To replenish  the collection, 36 lines (accessions) of synthetic hexaploid  wheat  (SHWs) developed at CIMMYT by crossing Triticum durum with Aegilops tauschii were studied.  Our research  was aimed at studying  the SHWs using a complex of morphological and economically  valuable traits in the environments of European Russia’s northwestern part (E30°, N59°), evaluating the reaction  of the SHWs to a photoperiod  and determining their genetic heterogeneity and similarities by gliadins as biochemical  markers. The results showed that the variability of different traits for SHWs fits into the framework of the genus  Triticum, and so SHWs can be classified as poorly domesticated forms. Their distinctive feature, valuable for wheat  breeding, is a large weight  of a thousand grains (up to 60.6 g). This trait was characterized by a low degree of variability and a low correlation  with other  traits. The reaction  of wheat  plants to the length  of the day is crucial for their transition  from vegetative to reproductive development. The SHWs studied differed from common wheat and one another by responses to the short day and by the length  of the ‘emergence-heading’ phase  if they grew under  the conditions of a long day. The delay in the development of plants with a short photoperiod ranged from 5.4 to 53.8 days. On a long day, the duration of the ‘emergence-heading’ phase  varied from 39.5 to 53.9 days. A possible genetic basis for the differences  identified is discussed.  To assess the diversity of SHWs, we also used  gliadin proteins as informative  biochemical  markers. It was revealed  that 21 SHWs were homogeneous, and the rest, heterogeneous. Forty-four different biotypes were found for the SHWs studied,  from which 36 were unique.  Relationships between biotypes have been  demonstrated using cluster analysis. It should be noted that 13 SHWs were unstable. In each of them, some plants differed from the others  in terms of a complex of morphological characters, reaction to a photoperiod, and gliadin patterns. It is possible that the instability of accessions  is the result of genome rearrangement in SHWs. SHW accessions  and the forms isolated from them are considered as sources of new genetic variability to improve common wheat.

1. Identification of Varieties and Registration of the Gene Pool of Cultivated Plants by Seed Proteins. St. Petersburg: VIR, 2000. (in Russian)

2. Lapochkina I.F., Iordanskaya I.V., Yachevskaya G.L., Labban A.A. Cytogenetic study of synthetic wheats from National Small Grain Collection of USDA-ARS in the conditions of Nechernozemnaya zone of Russia. Sel’skokhozyaistvennaya Biologiya = Agricultural Biology. 2014;3:77-82. DOI 10.15389/agrobiology.2014.3.77rus. (in Russian)

3. Merezhko A.F., Udachin R.A., Zuev Ye.V., Filatenko A.A., Serbin A.A., Lyapunova O.A., Kosov V.Yu., Kurkiev U.K., Okhotnikova T.V., Navruzbekov N.A., Boguslavsky R.L., Abdulaeva A.K., Chikida N.N., Mitrofanova O.P., Potokina S.A. Guidelines on the Replenishment, Preservation in Living Form, and Study of the World Collection of Wheat, Aegilops, and Triticale. St. Petersburg: VIR Publ., 1999. (in Russian)

4. Khakimova A.G., Pukkenen V.P., Dulneva N.D., Shestobitov V.V., Gubareva N.K., Martynenko N.M., Mitrofanova O.P. Catalog of the World Collection of VIR. Wheat. Synthetic Hexaploid Wheat: Characteristics of 36 Accessions from CIMMYT Added to the VIR Collection (Certificate Data, Morphological Description, Economically Valuable Signs, Registration According to Gliadin Spectra). St. Petersburg, 2018. (in Russian)

5. Shamanin V.P., Pototskaya I.V., Shepelev S.S., Pozherukova V.E., Chursin A.S., Morgunov A.I. Synthetic Wheat, a Monograph. Omsk, 2018. (in Russian)

6. The CMEA Wide Unified Classifier of the Genus Triticum L. Leningrad, 1989. (in Russian)

7. Shcherban A.B. The reorganization of plant genomes during allopolyploidization. Russ. J. Genet.: Appl. Res. 2013;3(6):444-450. DOI 10.1134/S2079059713060087.

8. Beales J., Turner A., Griffiths S., Snape J.W., Laurie D.A. A pseudo-response regulator is misexpressed in the photoperiod insensitive Ppd-D1a mutant of wheat (Triticum aestivum L.). Theor. Appl. Genet. 2007;115:721-733. DOI 10.1007/s00122-007-0603-4.

9. del Blanco I.A., Rajaram S., Kronstad W.E. Agronomic potential of synthetic hexaploid wheat-derived populations. Crop Sci. 2001; 41:670-676. https://dl.sciencesocieties.org/publications/cs/abstracts/41/3/670.

10. Diaz A., Zikhali M., Turner A.S., Isaac P., Laurie D.A. Copy number variation affecting the Photoperiod-B1 and Vernalization-A1 genes is associated with altered flowering time in wheat (Triticum aestivum). Plos One. 2012;7(3):e33234. DOI 10.1371/journal.pone003234.

11. Frizon P., Brammer S.P., Lima M.I.P.M., de Castro R.L., Deuner C.C. Genetic stability in synthetic wheat accessions: cytogenetic evaluation as a support in breeding programs. Ciência Rural. 2017;47(4): 1-7. DOI 10.1590/0103-8478cr20160314.

12. Gill B.S., Raupp W.J., Sharma H.C., Browder L.E., Hatchett J.H., Harvey T.L., Moseman J.G., Waines J.G. Resistance in Aegilops squarrosa to wheat leaf rust, wheat powdery mildew, greenbug, and hessian fly. Plant Dis. 1986;70:553-556. https://www.apsnet.org/publications/PlantDisease/BackIssues/Documents/1986Articles/PlantDisease70n06_553.PDF.

13. Gul Kazi A., Rasheed A., Mahmood T., Mujeeb-Kazi A. Molecular and morphological diversity with biotic stress resistances of high 1000-grain weight synthetic hexaploid wheats. Pak. J. Bot. 2012; 44(3):1021-1028. https://www.researchgate.net/publication/260594114_Molecular_and_morphological_diversity_with_biotic_stress_ resistances_of_high_1000-grain_weight_synthetic_hexaploid_ wheats.

14. Huang L., Wang Q., Zhang L.-Q., Yuan Z.-W., Wang J.-R., Zhang H.-G., Zheng Y.-L., Liu D.-C. Haplotype variations of gene Ppd-D1 in Aegilops tauschii and their implications on wheat origin. Genet. Res. Crop Evol. 2012;59:1027-1032. DOI 10.1007/s10722-011-9741-2.

15. Kihara H. Discovery of the DD-analyser, one of the ancestors of Triticum vulgare. Agric. Hortic. 1944;19:889-890.

16. Li A., Liu D., Yang W., Kishii M., Mao L. Synthetic hexaploid wheat: yesterday, today, and tomorrow. Engineering. 2018;4:552-558. DOI 10.1016/j.eng.2018.07.001.

17. McFadden E.S., Sears E.R. The origin of Triticum spelta and its freethreshing hexaploid relatives. J. Hered. 1946;37(4):107-116. DOI 10.1093/oxfordjournals.jhered.a105590.

18. Mujeeb-Kazi A., Delgado R. A second, elite set of synthetic hexaploid wheats based upon multiple disease resistance. Ann. Wheat Newslett. 2001;47:114-115.

19. Mujeeb-Kazi A., Fuentes-Davila G., Delgado R., Rosas V., Cano S., Cortes A., Juarez L., Sanches J. Current status of D genome based, synthetic hexaploid wheats and the characterization of an elite subset. Ann. Wheat Newslett. 2000;46:76-79.

20. Mujeeb-Kazi A., Hettel G.P. (Eds.). Utilizing Wild Grass Biodiversity in Wheat Improvement: 15 years of Wide Cross Research at CIMMYT. CIMMYT Research Report No. 2, 1995.

21. Mujeeb-Kazi A., Rosas V., Roldan S. Conservation of the genetic variation of Triticum tauschii (Coss.) Schmalh. (Aegilops sguarrosa auct. non L.) in synthetic hexaploid wheat (T. turgidum L. s. lat. ×T. tauschii; 2n = 6x = 42, AABBDD) and its potential utilization for wheat improvement. Genet. Res. Crop Evol. 1996;39:129-134. Available at https://link.springer.com/article/10.1007%2FBF00126756#page-1.

22. Nishida H., Yoshida T., Kawakami K., Fujita M., Long B., Akashi Y., Laurie D.A., Kato K. Structural variation in the 5′ upstream region of photoperiod-insensitive alleles Ppd-A1a and Ppd-B1a identified in hexaploid wheat (Triticum aestivum L.) and their effect on heading time. Mol. Breeding. 2013;31:27-37. DOI 10.1007/s11032-012-9765-0.

23. Ogbonnaya F.C., Abdalla O., Mujeeb-Kazi A., Kazi A.G., Xu C.C., Gosman N., Lagudah E.S., Bonnett D., Sorrells M., Tsujimoto H. Synthetic hexaploids: harnessing species of the primery gene pool for wheat improvement. Plant Breed. Rev. 2013;37:35-122. DOI 10.1002/9781118497869.ch2.

24. Rasheed A., Saldar T., Gul-Kazi A., Mahmood T., Akram Z., MajeebKazi A. Characterization of HMW-GS and evaluation of their diversity in morphologically elite synthetic hexaploid wheats. Breed. Sci. 2012;62:365-370. DOI 10.1270/jsbbs.62.365.

25. Tonosaki K., Osabe K., Kawanabe T., Fujimoto R. The importance of reproductive barriers and the effect of allopolyploidization on crop breeding. Breed. Sci. 2016;66:333-349. DOI 10.1270/jsbbs.15114.

26. UniProt. Taxonomy – × Aegilotriticum (GENUS). 2019. Available at https://www.uniprot.org/taxonomy/289427.

27. van Ginkel M., Ogbonnaya F. Novel genetic diversity from synthetic wheats in breeding cultivars for changing production conditions. Field Crops Res. 2007;104:86-94. DOI 10.1016/j.fcr.2007.02.005.

28. Wang D.-W., Li D., Wang J., Zhao U., Wang Z., Yue G., Liu X., Qin H., Zhang K., Dong L., Wang D. Genome-wide analysis of complex wheat gliadins, the dominant carriers of celiac disease epitopes. Sci. Rep. 2017,7:44609. DOI 10.1038/srep44609.

29. Wilhelm E.P., Turner A.S., Laurie D.A. Photoperiod insensitive Ppd-A1a mutations in tetraploid wheat (Triticum durum Desf.). Theor. Appl. Genet. 2009;118:285-294. DOI 10.1007/s00122-008-0898-9.

30. Yan L., Liu Z., Xu H., Zhang X., Zhao A., Liang F., Xin M., Peng H., Yao Y., Sun Q., Ni Z. Transcriptome analysis reveals potential mechanisms for different size between natural and resynthesized allohexaploid wheats with near-identical AABB genomes. BMC Plant Biol. 2018;18:28. DOI 10.1186/s12870-018-1248-y.

31. Yang W., Liu D., Li J., Zhang L., Wei H., Hu X., Zheng Y., He Z., Zou Y. Synthetic hexaploid wheat and its utilization for wheat genetic improvement in China. J. Genet. Genomics. 2009;36:539-546. DOI 10.1016/S1673-8527(08)60145-9.