Chromosomal mapping of Hessian fly-resistance gene H13 in the D genome of wheat

Abstract

Monosomic analysis was used to locate a single, dominant, Hessian fly-resistance gene (H13) present in the D genome of common wheat germpiasm KS8 1H 1640HF derived from Aegilops squarrosa L. The seven D-genome monosomics (1D-7D) of the cultivar Wichita were crossed with KS8 1H 1640HF and 41-chromosome F₁ plants were allowed to self. Among the seven D-genome monosomic F₂ families, six gave 3:1 segregation for the H13 gene in reaction to Hessian fly biotype D. Critical monosomic 6D F₂ plants deviated significantly from 3:1 ratio and indicated that the H13 gene is located on chromosome 6D. The F₃ families derived from resistant F₂ plants were again tested for H13 gene segregation. Six monosomic F₃ families gave resistant to segregating reaction in a ratio of 1:2 and only monosomic 6D F₃ families deviated significantly from the 1:2 ratio. N-banding analysis indicated that the few segregating monosomic 6D F₃ families encountered arose from cytological abnormalities in a small fraction of the resistant F₂ plants. Telocentric analysis was used to map the H13 gene on 6Dq (long arm) 35.0 ± 8.0 recombination units from the centromere.