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2002; He et al. 2003; Ferguson et al. 2004;
Moretzsohn et al. 2004; He et al. 2005; Moret-
zsohn et al. 2005; Palmieri et al. 2005; Bravo
et al. 2006; Budiman et al. 2006; Gimenes et al.
2007; Proite et al. 2007; Wang et al. 2007; Cuc
et al. 2008; Naito et al. 2008; Liang et al. 2009;
Moretzsohn et al. 2009; Song et al. 2010; Yuan
et al. 2010; Koilkonda et al. 2012; Macedo et al.
2012; Pandey et al. 2012) and molecular mark-
ers based on MITE markers (Shirasawa et al.
2012 and unpublished data). Generally, these
markers have shown a trend toward becoming
more informative, and now microsatellites, being
codominant and easy to score in the tetraploid
genome, are considered the molecular marker of
choice, with MITE markers also showing much
potential.
TxAG-6
A. batizocoi
×
[ A. cardenasii
×
A.
{
diogoi ]
4x . A total of 370 RFLP loci were
mapped onto 23 linkage groups, for a map dis-
tance of 2,210 cM (Burow et al. 2001). The map
was characterized by pairing of homoeologous
linkage groups, consistent with a disomic nature
of the cultigen. An AFLP-based A-genome map
was generated from an F 2 population developed
from the cross A. kuhlmannii x A. diogoi ; 102
markers were mapped over 1,068 cM (Milla
2003). A RAPD-based map of A. stenosperma
x A. cardenasii was developed by Garcia et al.
(2005). This map contained 167 RAPD and 39
RFLP loci spanning 800 cM and 11 linkage
groups.
The first microsatellite-based map of peanut
was developed with an F 2 population derived
from a cross between A genome diploids A.
duranensis and A. stenosperma , and had 170
microsatellite markers on 11 linkage groups cov-
ering 1,231 cM (Moretzsohn et al. 2005). Sub-
sequently a microsatellite map of the B genome
based on a cross of A. ipaensis and the closely
related A. magna was produced (Moretzsohn
et al. 2009). This map had 10 linkage groups,
with 149 loci spanning a very similar total map
distance of 1294 cM. The comparison of 51
shared markers between these two maps revealed
high levels of synteny, with all but one of the
B linkage groups showing a single main cor-
respondence to an A linkage group. Fonceka
et al. (2009) developed a map of 289 SSR mark-
ers using a BC 1 population between the culti-
var Fleur 11 and a synthetic amphidiploid ( A.
duranensis x A. ipaensis ) 4x . This map again
showed good colinearity between the A and B
subgenomes in general, though several inver-
sions of order were noted.
A higher-density version of the diploid map
based on the cross of A. duranensis and A.
stenosperma published by Moretzsohn et al.
(2005) was reported by Leal-Bertioli et al.
(2009). This map consisted of a total of 369
markers, including 188 SSRs and 80 legume
anchor markers, 46 AFLPs, 32 NBS analogs,
17 SNPs, 4 RGA-RFLPs, and 2 RGA-SCAR
}
Maps Based on Crosses Involving Wild
Species
The very narrow genetic base of cultivated
peanut has provided a substantial obstacle
to genetic mapping using only cultivated
germplasm. This meant that maps were initially
generated using crosses involving wild species.
Subsequently mapping in cultivated x cultivated
crosses has advanced considerably (see discus-
sion later in the chapter). In spite of this, mapping
using crosses involving wild species is likely to
continue to be important. Wilds are a source of
new alleles for cultivated peanut conferring, for
instance, strong disease resistances; the greater
DNA polymorphism of the wilds allows for
higher resolution mapping; also, diploid genetics
simplifies genetic analysis and the use of some
marker types (notably marker types based on sin-
gle nucleotide polymorphisms, or SNPs).
The first genetic linkage map of peanut was
developed using an F 2 population of a cross
between A-genome diploids A. stenosperma and
A. cardenasii . The 117 mapped RFLP markers
were distributed among 11 linkage groups over
1,063 cM (Halward et al. 1993). A second map
was constructed from a tetraploid cross of the
cultivar Florunner
×
the synthetic amphidiploid
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