Stacking small segments of the 1D chromosome of bread wheat containing major gluten quality genes into durum wheat: transfer strategy and breeding prospects

Using a chromosome engineering strategy, we previously developed two durum wheat recombinant lines, each containing on chromosome 1A a short segment of bread wheat chromosome 1D with either the Glu-D1 (PL line) or the Gli-D1/Glu-D3 (PS line) genes. Since PL and PS transfers produced substantial but different effects on durum gluten properties, in the present work stacking of their 1DS and 1DL segments into the same chromosome 1A was undertaken to investigate their combined effect in durum wheat and to potentially widen the spectrum of the crop end-uses. Development of genetic and genomic in situ hybridization (GISH)-based physical maps of PS and PL recombinant arms facilitated selection of carriers of the double-recombinant (PS + PL) 1A chromosome among F-2 progeny from the PS x PL cross. With the 1DS transfer spanning the terminal 17% of recombinant 1AS, and the interstitial 1DL segment occupying 16% of recombinant 1AL, PS + PL chromosomes were generated by pairing events occurred with a 68.4% frequency in 1A regions shared by parental chromosomes. Homozygous double-recombinant F-3 plants exhibited no significant differences for relevant agronomic traits compared to sib lines possessing either one or no 1D segment. Among quality parameters preliminarily assessed, SDS sedimentation values increased by 12% in PS and by over 32 and 38% in PL and PS + PL lines, respectively, compared to null controls. As a whole, the novel recombinant genotype offers good prospects for direct exploitation in breeding, and hence for an effective contribution to the enhancement of the crop value.