Transfer of alien Hessian fly resistance genes to durum wheat by induced homoeologous recombination.

摘要

The Hessian fly resistance gene H21 is present in the wheat-rye whole-arm translocation T2BS·2RL and was recently transferred to durum wheat. However, homozygous T2BS·2RL durum plants are almost completely sterile. The first objective of this study was to reduce the rye segment in T2BS·2RL using ph-mediated recombination, and thereby making this gene available for durum wheat breeding. A total of 39 recombinants were recovered from a population of 512 plants (7.6%) involving about 10% of the distal regions of the long arms of 2R and 2B. Ten primary recombinants were tested for their resistance to Hessian fly. Three recombinants with about the distal 10% of the 2BL arm derived from 2RL were resistant and, thus, had the H21 gene. Two recombinants with very distal 2RL segments and three recombinants with the distal 10% of the 2RL arm derived from 2BL were susceptible to Hessian fly and did not retain the H21 gene. The remaining two recombinants consisted of almost the complete 2RL arm with very distal 2BL segments were resistant and still had the resistance gene H21. The distal primary recombinants with the H21 were vigorous, had normal seed set, and can now be used in the durum wheat improvement. The second objective of this study was to transfer the Aegilops tauschii-derived Hessian fly resistance genes (H22, H23, H24 and H26) from common wheat to durum wheat. A total of 2,053 segregating BC₁F₁ were tested against Hessian fly and resistant plants (1,132) were backcrossed again with LDN 5D(5B) to produce BC₂ F₁ and selfed to produce BC₁F₂. Microsatellite analysis indicated that H22 recombinants were recovered and can be described as T1AS-1DS·1DL. The recombinant involving H23 probably consisted of the whole short arm of 6D and long arm of 6A described as T6DS·6AL. Both recombinants can be used in durum wheat improvement. In addition, monosomic substitution lines were recovered for the remaining resistance genes H24 and H26. These monosomic substitution lines are useful germplasm for further manipulation aimed to transfer genes H24 and H26 to durum wheat.