title: Genetic analysis of the interaction between Allium species and arbuscular mycorrhizal fungi.
abstract: The response of Allium cepa, A. roylei, A. fistulosum, and the hybrid A. fistulosum × A. roylei to the arbuscular mycorrhizal fungus (AMF) Glomus intraradices was studied. The genetic basis for response to AMF was analyzed in a tri-hybrid A. cepa × (A. roylei × A. fistulosum) population. Plant response to mycorrhizal symbiosis was expressed as relative mycorrhizal responsiveness (R') and absolute responsiveness (R). In addition, the average performance (AP) of genotypes under mycorrhizal and non-mycorrhizal conditions was determined. Experiments were executed in 2 years, and comprised clonally propagated plants of each genotype grown in sterile soil, inoculated with G. intraradices or non-inoculated. Results were significantly correlated between both years. Biomass of non-mycorrhizal and mycorrhizal plants was significantly positively correlated. R' was negatively correlated with biomass of non-mycorrhizal plants and hence unsuitable as a breeding criterion. R and AP were positively correlated with biomass of mycorrhizal and non-mycorrhizal plants. QTLs contributing to mycorrhizal response were located on a linkage map of the A. roylei × A. fistulosum parental genotype. Two QTLs from A. roylei were detected on chromosomes 2 and 3 for R, AP, and biomass of mycorrhizal plants. A QTL from A. fistulosum was detected on linkage group 9 for AP (but not R), biomass of mycorrhizal and non-mycorrhizal plants, and the number of stem-borne roots. Co-segregating QTLs for plant biomass, R and AP indicate that selection for plant biomass also selects for enhanced R and AP. Moreover, our findings suggest that modern onion breeding did not select against the response to AMF, as was suggested before for other cultivated species. Positive correlation between high number of roots, biomass and large response to AMF in close relatives of onion opens prospects to combine these traits for the development of more robust onion cultivars.
authors.affiliation: Department of Plant Breeding, Plant Research International, Wageningen University and Research Centre, Wageningen, The Netherlands.
authors.forename: Guillermo A
authors.initials: GA
authors.lastname: Galván
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Kuyper
authors.forename: Karin
authors.initials: K
authors.lastname: Burger
authors.forename: L C Paul
authors.initials: LC
authors.lastname: Keizer
authors.forename: Rolf F
authors.initials: RF
authors.lastname: Hoekstra
authors.forename: Chris
authors.initials: C
authors.lastname: Kik
authors.forename: Olga E
authors.initials: OE
authors.lastname: Scholten
mesh_terms: D054458:Amplified Fragment Length Polymorphism Analysis; D018533:Biomass; D002874:Chromosome Mapping; D032461:Chromosomes, Plant; D008040:Genetic Linkage; D005838:Genotype; D055137:Glomeromycota / Q000254:growth & development; D038821:Mycorrhizae / Q000254:growth & development*; D019697:Onions / Q000235:genetics* / Q000254:growth & development* / Q000382:microbiology; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development; D018517:Plant Roots / Q000235:genetics* / Q000254:growth & development* / Q000382:microbiology; D040641:Quantitative Trait Loci; D012987:Soil / Q000032:analysis; D013559:Symbiosis
chemical_list: D012987:Soil