title: Genome mapping of postzygotic hybrid necrosis in an interspecific pear population.
abstract: Deleterious epistatic interactions in plant inter- and intraspecific hybrids can cause a phenomenon known as hybrid necrosis, characterized by a typical seedling phenotype whose main distinguishing features are dwarfism, tissue necrosis and in some cases lethality. Identification of the chromosome regions associated with this type of incompatibility is important not only to increase our understanding of the evolutionary diversification that led to speciation but also for breeding purposes. Development of molecular markers linked to the lethal genes will allow breeders to avoid incompatible inbred combinations that could affect the expression of important agronomic tratis co-segregating with these genes. Although hybrid necrosis has been reported in several plant taxa, including Rosaceae species, this phenomenon has not been described previously in pear. In the interspecific pear population resulting from a cross between PEAR3 (Pyrus bretschneideri × Pyrus communis) and 'Moonglow' (P. communis), we observed two types of hybrid necrosis, expressed at different stages of plant development. Using a combination of previously mapped and newly developed genetic markers, we identified three chromosome regions associated with these two types of lethality, which were genetically independent. One type resulted from a negative epistatic interaction between a locus on linkage group 5 (LG5) of PEAR3 and a locus on LG1 of 'Moonglow', while the second type was due to a gene that maps to LG2 of PEAR3 and which either acts alone or more probably interacts with another gene of unknown location inherited from 'Moonglow'.
authors.affiliation: Research and Innovation Centre, Fondazione Edmund Mach, Via Mach 1, 38010 San Michele all'Adige (TN), Italy; The New Zealand Institute for Plant & Food Research Limited, Palmerston North Research Centre, Palmerston North, New Zealand; Institut de Recherche en Horticulture et Semences - UMR1345, Institut National de la Recherche Agronomique (INRA), SFR 4207 Quasav, 42 rue Georges Morel, F-49071 Beaucouzé, France.
authors.forename: Sara
authors.initials: S
authors.lastname: Montanari
authors.affiliation: The New Zealand Institute for Plant & Food Research Limited, Motueka Research Centre , Motueka, New Zealand.
authors.forename: Lester
authors.initials: L
authors.lastname: Brewer
authors.affiliation: The New Zealand Institute for Plant & Food Research Limited, Motueka Research Centre , Motueka, New Zealand.
authors.forename: Robert
authors.initials: R
authors.lastname: Lamberts
authors.affiliation: Research and Innovation Centre, Fondazione Edmund Mach , Via Mach 1, 38010 San Michele all'Adige (TN), Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Velasco
authors.affiliation: Research and Innovation Centre, Fondazione Edmund Mach , Via Mach 1, 38010 San Michele all'Adige (TN), Italy.
authors.forename: Mickael
authors.initials: M
authors.lastname: Malnoy
authors.affiliation: Institut de Recherche en Horticulture et Semences - UMR1345, Institut National de la Recherche Agronomique (INRA), SFR 4207 Quasav, 42 rue Georges Morel, F-49071 Beaucouzé, France; Institut de Recherche en Horticulture et Semences - UMR1345, Université d'Angers, F-49045 Angers, France.
authors.forename: Laure
authors.initials: L
authors.lastname: Perchepied
authors.affiliation: Institut de Recherche en Horticulture et Semences - UMR1345, Institut National de la Recherche Agronomique (INRA), SFR 4207 Quasav, 42 rue Georges Morel, F-49071 Beaucouzé, France; Institut de Recherche en Horticulture et Semences - UMR1345, Université d'Angers, F-49045 Angers, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Guérif
authors.affiliation: Institut de Recherche en Horticulture et Semences - UMR1345, Institut National de la Recherche Agronomique (INRA), SFR 4207 Quasav, 42 rue Georges Morel, F-49071 Beaucouzé, France; Institut de Recherche en Horticulture et Semences - UMR1345, Université d'Angers, F-49045 Angers, France.
authors.forename: Charles-Eric
authors.initials: CE
authors.lastname: Durel
authors.affiliation: The New Zealand Institute for Plant & Food Research Limited, Hawke's Bay Research Centre , Havelock North, New Zealand .
authors.forename: Vincent G M
authors.initials: VG
authors.lastname: Bus
authors.affiliation: The New Zealand Institute for Plant & Food Research Limited, Palmerston North Research Centre , Palmerston North, New Zealand.
authors.forename: Susan E
authors.initials: SE
authors.lastname: Gardiner
authors.affiliation: The New Zealand Institute for Plant & Food Research Limited, Palmerston North Research Centre , Palmerston North, New Zealand.
authors.forename: David
authors.initials: D
authors.lastname: Chagné