Reactions of Eleven Tetraploid and Hexaploid Wheat Introductions to Hessian Fly

The expression of resistance of wheat ( Triticum spp.) to the Hessian fly ( Mayetiola destructor Say) is affected by cultivar, biotype, and temperature. The objectives of this study were to: (i) evaluate the resistance of seven durum wheat ( T. durum desf.) and four common wheat ( T. aestivum L.) introductions, and three wheat checks to biotypes B, D, and L of Hessian fly, and (ii) examine their expressions of resistance to biotype D at three temperatures. Tests against the three biotypes were conducted in a greenhouse at 19 ± 2 °C; temperature experiments were conducted in controlled environment chambers at 19, 23, and 26 ± 2 °C. In all experiments, 30 seeds of each wheat line were planted in a row in a 54 ✕ 36 ✕ 8 cm wooden flat filled with a greenhouse soil mixture. Twenty‐one days after infestation, the seedlings were classified as resistant or susceptible. The 11 wheat introductions were resistant to biotypes B, D, and L under greenhouse conditions. Nearly all seedlings of the durum lines Portugal 2536, Portugal 2852, Rebeiro, BD 3431 and IN 8464( H5H5 ) were resistant at 19, 23, and 26 °C. Fewer seedlings of the durum lines BD 3414, BD 3885, and PI 422297; and of the common wheat lines PI 86202, PI 117499, PI 134867, PI 321644, and ‘Abe’( H5H5 ) were resistant at temperatures > 19 °C. Resistance conferred by the H5 gene was expressed in a greater percentage of seedlings of IN 8464 than Abe, especially at temperatures > 19 °C. These results are of practical importance to wheat breeders in tropical or subtropical regions of the world where Hessian fly is a serious pest of wheat.