A genetic map of tetraploid Paspalum notatum Flügge (bahiagrass) based on single-dose molecular markers
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2007-01-29
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Springer Science+Business Media B.V.
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Descripción
Paspalum notatum Flu¨ gge is a warmseason
forage grass with mainly diploid (2n =
20) and autotetraploid (2n = 40) representatives.
Diploid races reproduce sexually and
require crosspollination due to a self-incompatible
mating system, while autotetraploids
reproduce by aposporous apomixis. The objectives
of this work were to develop a genetic
linkage map of Paspalum notatum Flu¨gge at
the tetraploid level, identify the linkage/s
group/s associated with apomixis and carry
out a general characterization of its mode of
inheritance. A pseudo test-cross F1 family of
113 individuals segregating for the mode of
reproduction was obtained by crossing a synthetic
completely sexual tetraploid plant
(Q4188) as female parent with a natural
aposporous individual (Q4117) as pollen donor.
Map construction was based on single-dose
markers (SDAFs) segregating from both parents.
Two linkage maps (female and male)
were constructed. Within each map, homologous
groups were assembled by detecting
repulsion-phase linked SDAFs. Putative
Q4188 and Q4117 homolog groups were
identified by mapping shared single dose markers
(BSDF). The Q4188 map consisted of 263
markers distributed on 26 co-segregation
groups over a total genetic distance of 1.590.6
cM, while the Q4117 map contained 216 loci
dispersed on 39 co-segregation groups along
2.265.7 cM, giving an estimated genome coverage
of 88% and 83%, respectively. Seven and
12 putative homologous chromosomes were
detected within Q4188 and Q4117 maps,
respectively. Afterward, ten female and male
homologous chromosomes were identified by
mapping BSDFs. In the Q4117 map, a single
linkage group was associated with apospory. It
was characterized by restriction in recombination
and preferential chromosome pairing. A
BPSD marker mapping within this group
allowed the detection of the female homolog
and the putative four male groups of the set
carrying apospory.
Palabras clave
Apospory, Mapping in autopolyploids, Paspalum notatum, Single dose markers