Multilocus half-tetrad analysis and centromere mapping in citrus: evidence of SDR mechanism for 2n megagametophyte production and partial chiasma interference in mandarin cv 'Fortune'

Publication Overview
TitleMultilocus half-tetrad analysis and centromere mapping in citrus: evidence of SDR mechanism for 2n megagametophyte production and partial chiasma interference in mandarin cv 'Fortune'
AuthorsCuenca J, Froelicher Y, Aleza P, Juarez J, Navarro L, Ollitrault P
TypeJournal Article
Journal NameHeredity
Volume107
Issue5
Year2011
Page(s)462-470
CitationCuenca J, Froelicher Y, Aleza P, Juarez J, Navarro L, Ollitrault P. Multilocus half-tetrad analysis and centromere mapping in citrus: evidence of SDR mechanism for 2n megagametophyte production and partial chiasma interference in mandarin cv 'Fortune'. 2011. Heredity 107(5):462-470.

Abstract

The genetic structure of 2n gametes and, particularly, the parental heterozygosity restitution at each locus depends on the meiotic process by which they originated, with first-division restitution and second-division restitution (SDR) being the two major mechanisms. The origin of 2n gametes in citrus is still controversial, although sexual polyploidisation is widely used for triploid seedless cultivar development. In this study, we report the analysis of 2n gametes of mandarin cv ‘Fortune’ by genotyping 171 triploid hybrids with 35 simple sequence repeat markers. The microsatellite DNA allele counting-peak ratios method for allele-dosage evaluation proved highly efficient in segregating triploid progenies and allowed half-tetrad analysis (HTA) by inferring the 2n gamete allelic configuration. All 2n gametes arose from the female genitor. The observed maternal heterozygosity restitution varied between 10 and 82%, depending on the locus, thus SDR appears to be the mechanism underlying 2n gamete production in mandarin cv ‘Fortune’. A new method to locate the centromere, based on the best fit between observed heterozygosity restitution within a linkage group and theoretical functions under either partial or no chiasmata interference hypotheses was successfully applied to linkage group II. The maximum value of heterozygosity restitution and the pattern of restitution along this linkage group would suggest there is partial chiasma interference. The implications of such a restitution mechanism for citrus breeding are discussed.
Stocks
This publication contains information about 9 stocks:
Stock NameUniquenameType
FortuneFortunecultivar
Common MandarinCommon Mandarincultivar
EllendaleEllendalecultivar
MinneolaMinneolacultivar
MurcottMurcottcultivar
Fortune_x_Common MandarinFortune_x_Common Mandarinpopulation
Fortune_x_EllendaleFortune_x_Ellendalepopulation
Fortune_x_MinneolaFortune_x_Minneolapopulation
Fortune_x_MurcottFortune_x_Murcottpopulation
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URLhttp://dx.doi.org/10.1038/hdy.2011.33