Production of synthetic wheat lines to exploit the genetic diversity of emmer wheat and D genome containing Aegilops species in wheat breeding

Ghader Mirzaghaderi,Mohammad Majdi,Rahman Ebrahimzadegan,Ali-Akbar Mozafari,Zinat Abdolmalaki,Fatemeh Orooji,Farshid Bahmani

doi:10.1038/s41598-020-76475-7

Abstract

Due to the accumulation of various useful traits over evolutionary time, emmer wheat (Triticum turgidum subsp. dicoccum and dicoccoides, 2n = 4x = 28; AABB), durum wheat (T. turgidum subsp. durum, 2n = 4x = 28; AABB), T. timopheevii (2n = 4x = 28; AAGG) and D genome containing Aegilops species offer excellent sources of novel variation for the improvement of bread wheat (T. aestivum L., AABBDD). Here, we made 192 different cross combinations between diverse genotypes of wheat and Aegilops species including emmer wheat × Ae. tauschii (2n = DD or DDDD), durum wheat × Ae. tauschii, T. timopheevii × Ae. tauschii, Ae. crassa × durum wheat, Ae. cylindrica × durum wheat and Ae. ventricosa × durum wheat in the field over three successive years. We successfully recovered 56 different synthetic hexaploid and octaploid F2 lines with AABBDD, AABBDDDD, AAGGDD, D1D1XcrXcrAABB, DcDcCcCcAABB and DvDvNvNvAABB genomes via in vitro rescue of F1 embryos and spontaneous production of F2 seeds on the Fl plants. Cytogenetic analysis of F2 lines showed that the produced synthetic wheat lines were generally promising stable amphiploids. Contribution of D genome bearing Aegilops and the less-investigated emmer wheat genotypes as parents in the crosses resulted in synthetic amphiploids which are a valuable resource for bread wheat breeding.

Highlights

IntroductionDue to the recent origination of bread wheat, the D subgenome of bread wheat is still substantially similar to the D genome of Ae. tauschii, such that introgression of D genome chromosome segments from Ae. tauschii into the wheat background does not result in significant deleterious genetic drag in hybrids: as a result, Ae. tauschii has been efficiently utilized for the improvement of common wheat for d ecades[12]
Due to the accumulation of various useful traits over evolutionary time, emmer wheat (Triticum turgidum subsp. dicoccum and dicoccoides, 2n = 4x = 28; AABB), durum wheat (T. turgidum subsp. durum, 2n = 4x = 28; AABB), T. timopheevii (2n = 4x = 28; AAGG) and D genome containing Aegilops species offer excellent sources of novel variation for the improvement of bread wheat (T. aestivum L., AABBDD)
Fifty six different synthetic hexa- and octaploid F 2 lines were recovered with AABBDD, AABBDDDD, AAGGDD, D1D1XcrXcrAABB, DcDcCcCcAABB or DvDvNvNvAABB genome complements; a subset of these lines were further analyzed by fluorescence in situ hybridization (FISH)

Summary

Introduction

Due to the recent origination of bread wheat, the D subgenome of bread wheat is still substantially similar to the D genome of Ae. tauschii, such that introgression of D genome chromosome segments from Ae. tauschii into the wheat background does not result in significant deleterious genetic drag in hybrids: as a result, Ae. tauschii has been efficiently utilized for the improvement of common wheat for d ecades[12] Useful traits such as tolerance to c old[13] and salt[14], leaf and stem rust r esistance[15] and resistance to cereal cyst and root-knot n ematodes[16,17] exist within of the allopolyploid Aegilops species containing a copy of the D genome: Ae. crassa 4x (2n = D1D1XcrXcr), Ae. crassa 6x (2n = D1D1XcrXcrDcrDcr), Ae. cylindrica (2n = DcDcCcCc), Ae. vavilovii (2n = D1D1XcrXcrSvSv), Ae. ventricosa (2n = DvDvNvNv) and Ae. juvenalis (2n = DjDjXjXjUjUj).

Objectives

Methods

Results

Discussion

Conclusion