Transfer of wheat-rye translocation chromosomes conferring resistance to Hessian fly from bread wheat into durum wheat

The Hessian fly, Mayetiola destructor (Say), is a damaging pest of bread wh eat, Triticum aestivum L., and durum wheat, T. turgidum L, ssp. durum Desf. Husn,, in many wheat production areas of the world. Breeding for host plan t resistance is the most agronomically desirable way to control this pest. Twenty-seven major genes conferring resistance to Hessian fly hale been ide ntified and used in wheat improvement. These genes confer resistance to spe cific biotypes of the Hessian fly, Recently, new sources of Hessian fly res istance derived from cultivated rye, Secale cereale L,, have been reported that confer resistance to all known biotypes of the Hessian fly, The resist ance gene H21 is present on the wheat-rye whole arm translocation T2BS . 2R #2L.H25 is present on an interstitial rye segment in the 4AL arm of the whe at-rye translocation chromosome Ti4AS . 4AL-6R#1L-4AL. The objective of the present study was to transfer H21 and H25 to tetraploid durum wheat, there by making these genes available for the improvement of durum wheat. Homozyg ous T2BS . 2R#2L and Ti4AS . 4AL-6R#1L-4AL translocation durum lines were r ecovered that expressed the H21 and H25 resistance, The H25 durum transloca tion line was vigorous and set seeds similar to the durum wheat parental cu ltivar, Thus, the H25 transfer can be used directly in durum wheat improvem ent. Plant vigor and seed set of the H21 durum translocation line was drast ically reduced, indicating that the missing 2BL arm in this translocation h as genes that are essential for normal plant vigor and fertility. Further c hromosome engineering is required to shorten the rye segment in this transl ocation before H21 can be used in durum breeding.