Dissection of a major QTL qhir1 conferring maternal haploid induction ability in maize.
Among the qhir11 and qhir12 sub-regions of a major QTL qhir1, only qhir11 has significant effect on maternal haploid induction, segregation distortion and kernel abortion. In vivo haploid induction in maize can be triggered in high frequencies by pollination with special genetic stocks called haploid inducers. Several genetic studies with segregating populations from non-inducer x inducer crosses identified a major QTL, qhir1, on chromosome 1.04 contributing to in vivo haploid induction. A recent Genome Wide Association Study using 51 inducers and 1482 non-inducers also identified two sub-regions within the qhir1 QTL region, named qhir11 and qhir12; qhir12 was proposed to be mandatory for haploid induction because the haplotype of qhir11 was also present in some non-inducers and putative candidate genes coding for DNA and amino acid binding proteins were identified in the qhir12 region. To characterize the effects of each sub-region of qhir1 on haploid induction rate, F2recombinants segregating for one of the sub-regions and fixed for the other were identified in a cross between CML269 (non-inducer) and a tropicalized haploid inducer TAIL8. To quantify the haploid induction effects of qhir11 and qhir12, selfed progenies of recombinants between these sub-regions were genotyped. F3plants homozygous for qhir11 and/or qhir12 were identified, and crossed to a ligueless tester to determine their haploid induction rates. The study revealed that only the qhir11 sub-region has a significant effect on haploid induction ability, besides causing significant segregation distortion and kernel abortion, traits that are strongly associated with maternal haploid induction. The results presented in this study can guide fine mapping efforts of qhir1 and in developing new inducers efficiently using marker assisted selection.
International Maize and Wheat Improvement Center (CIMMYT), ICRISAT campus, Patancheru, Greater Hyderabad, 502324, India.
Sudha K
SK
Nair
Institute of Plant Breeding, Seed Science and Population Genetics, University of Hohenheim, 70593, Stuttgart, Germany.
Willem
W
Molenaar
Institute of Plant Breeding, Seed Science and Population Genetics, University of Hohenheim, 70593, Stuttgart, Germany.
Albrecht E
AE
Melchinger
International Maize and Wheat Improvement Center (CIMMYT), ICRAF campus, UN Avenue, Gigiri, P.O.Box 1041-00621, Nairobi, Kenya.
Prasanna M
PM
Boddupalli
International Maize and Wheat Improvement Center (CIMMYT), Apdo. Postal 6-641, 06600, Mexico, D.F, Mexico.
Leocadio
L
Martinez
International Maize and Wheat Improvement Center (CIMMYT), Apdo. Postal 6-641, 06600, Mexico, D.F, Mexico.
Luis Antonio
LA
Lopez
International Maize and Wheat Improvement Center (CIMMYT), ICRAF campus, UN Avenue, Gigiri, P.O.Box 1041-00621, Nairobi, Kenya. v.chaikam@cgiar.org.
Vijay
http://orcid.org/0000-0002-5046-1097
V
Chaikam
D018744:DNA, Plant / Q000235:genetics; D005787:Gene Frequency; D056726:Genetic Association Studies; D005838:Genotype; D006238:Haploidy; D006239:Haplotypes; D010641:Phenotype; D040641:Quantitative Trait Loci; D011995:Recombination, Genetic; D012639:Seeds / Q000235:genetics; D003313:Zea mays / Q000235:genetics*
D018744:DNA, Plant