HESSIAN FLY-RESISTANCE GENE H26 TRANSFERRED FROM TRITICUM-TAUSCHII TOCOMMON WHEAT

There is a continuing need for enhanced genetic diversity in common wh eat (Triticum aestivum L.) for resistance to the Hessian fly (Mayetiol a destructor Say). The objectives of this study were (i) to transfer a gene for Hessian fly resistance from the accession TA 2473 of the wil d diploid goatgrass T. tauschii (Coss.) Schmal. into an elite, hexaplo id wheat genotype and (ii) to determine the chromosomal location of th e gene. The F-1 and BC1 progenies from the cross 'Karl'/TA 2473 were m ale-sterile and set very few backcross seed, but seven BC2F2-derived l ines were resistant or segregating for resistance to Biotype L of Hess ian fly. Homozygous resistant BC2F4 and BC2F5 progeny within those lin es were crossed to 'Wichita'-based stocks monosomic for six of the sev en D-genome chromosomes and to tester stocks carrying the genes H13, H 22, H23, H24, and an unnamed gene, all transferred previously from T. tauschii. Segregation of F-2 plants from those crosses showed that res istance derived from TA 2473 is governed by one dominant gene located on chromosome 4D. This gene, designated herein as H26, is the only Hes sian fly-resistance gene known to be located on 4D. Gene H26 condition s a high level of antibiosis to Biotype L and has been transferred int o a germplasm line, KS92WGRC26, which has most of the desirable agrono mic traits of its recurrent parent, Karl. Therefore, H26 is expected t o be a useful addition to the set of Hessian fly-resistance genes avai lable to wheat breeders.