Fine Mapping of qhir8 in Maize

Abstract

The doubled-haploid (DH) technology has become an important tool for line development in modern maize breeding. However, the genetic basis of haploid induction remains elusive. In previous QTL mapping research, qhir8 besides qhir1 significantly affected haploid induction rate (HIR). Our objective was to fine map qhir8 and assess its effect on HIR, segregation distortion (SD) and embryo abortion (EmA). A total of 3989 F₂ plants from the cross of inducers CAUHOI and UH400 were screened for recombinants in the qhir8 region. F₂ plants and F₃ plants from selfing progenies of 34 recombinant F₂ plants were evaluated for HIR, SD and EmA. In parallel, we developed 31 new markers providing good coverage of the qhir8 region. We confirmed that qhir8 has an increasing effect on HIR and EmA, but not on SD. Moreover, we successfully narrowed down the qhir8 locus to a 789 kb region flanked by markers 4292232 and umc1867.