title: Recombination and genetic variance among maize doubled haploids induced from F1and F2plants.
abstract: Inducing maize doubled haploids from F2plants (DHF2) instead of F1plants (DHF1) led to more recombination events. However, the best DHF2 lines did not outperform the best DHF1 lines. Maize (Zea mays L.) breeders rely on doubled haploid (DH) technology for fast and efficient production of inbreds. Breeders can induce DH lines most quickly from F1plants (DHF1), or induce DH lines from F2plants (DHF2) to allow selection prior to DH induction and have more recombinations. Our objective was to determine if the additional recombinations in maize DHF2 lines lead to a larger genetic variance and a superior mean of the best lines. A total of 311 DHF1 and 241 DHF2 lines, derived from the same biparental cross, were crossed to two testers and evaluated in multilocation trials in Europe and the US. The mean number of recombinations per genome was 14.48 among the DHF1 lines and 21.38 among the DHF1 lines. The means of the DHF1 and DHF2 lines did not differ for yield, moisture, and plant height. The genetic variance was higher among DHF2 lines than among DHF1 lines for moisture, but not for yield and plant height. The ratio of repulsion to coupling linkages, which was estimated from genomewide marker effects, was higher among DHF1 lines than among DHF2 lines for moisture, but not for yield and plant height. The higher genetic variance for moisture among DHF2 lines did not lead to lower moisture of the best 10 % of the lines. Our results indicated that the decision of inducing DH lines from F1or F2plants needs to be made from considerations other than the performance of the resulting DHF1 or DHF2 lines.
authors.affiliation: Syngenta Seeds, LLC, 317 330th Street, Stanton, MN, 55018, USA.|Department of Agronomy and Plant Genetics, University of Minnesota, 411 Borlaug Hall, 1991 Upper Buford Circle, Saint Paul, MN, 55108, USA.
authors.forename: Joshua A
authors.initials: JA
authors.lastname: Sleper
authors.affiliation: Department of Agronomy and Plant Genetics, University of Minnesota, 411 Borlaug Hall, 1991 Upper Buford Circle, Saint Paul, MN, 55108, USA. bernardo@umn.edu.
authors.forename: Rex
authors.identifier: http://orcid.org/0000-0003-3323-4690
authors.initials: R
authors.lastname: Bernardo
mesh_terms: D003433:Crosses, Genetic; D018744:DNA, Plant / Q000235:genetics; D006238:Haploidy; D010641:Phenotype; D000069600:Plant Breeding; D020641:Polymorphism, Single Nucleotide; D011995:Recombination, Genetic; D003313:Zea mays / Q000235:genetics*
chemical_list: D018744:DNA, Plant