Mapping and Tagging of Simply Inherited Traits - Genetics, Genomics and Breeding of Crop Plants - page 129

resistant plants had thus far only been reported in cocklebur, Arabidopsis ,
and sunflower (Kolkman et al. 2004).
4.4 Male Sterility
4.4.1 Restoration of Cytoplasmic Male Sterility
Cytoplasmic male sterility (CMS) is characterized by the inability of a plant
to produce viable pollen while being female fertile. CMS is caused by a
mutation in the mitochondrial genome. In sunflower, the first reliable CMS
system (PET1) was reported by Leclercq (1969) in descendants of an
interspecific hybrid between Helianthus petiolaris Nutt. and the cultivated
sunflower. In the meantime, other sources of CMS have been found. Fertility
restoration of dominant nuclear genes is essential for hybrid breeding based
on CMS to obtain high yields of seeds. For PET1, a large number of fertility
restoration lines have been developed by plant breeders. One to four
dominant restorer genes have been described depending on the material
(Serieys 1996). However, in most of the elite sunflower lines, the two dominant
nuclear genes Rf1 and Rf2 are responsible for fertility restoration (Leclercq
1984). As Rf2 is present in nearly all inbred lines, including maintainers of
CMS, the Rf1 gene is most important for sunflower hybrid breeding.
The Rf1 gene was mapped by Gentzbittel et al. (1995, 1999) on group 6
of their RFLP and consensus map. Horn et al. (2003) constructed a linkage
map around the Rf1 gene using populations from the cross RHA325 x
HA342. They identified RAPD and AFLP markers closely linked to the
restorer gene Rf1 and converted two RAPD markers into SCAR markers.
Kusterer et al. (2005) saturated the chromosomal region of Rf1 with PCR
marker. They also used SSR markers and mapped marker ORS1030 on this
LG. ORS1030 was mapped on LG 13 on the public SSR map of sunflower.
Gentzbittel et al. (1999) mapped another fertility restoration locus of the
PET1 cytoplasm ( Msc1 ) on group 12 of their map. This linkage group
corresponds to LG 7 of the public map. Recently, Abratti et al. (2008) also
mapped a novel fertility restoration gene ( Rf3 ) for the PET1 cytoplasm on
LG 7. Rf3 was found in the public inbred line RHA340, which was derived
from a cross between H. argophyllus and HA89 as recurrent parent.
4.4.2 Nuclear Male Sterility
Nuclear male sterility (NMS) in sunflower was first discovered by Kuptsov
in 1934 (Gundaev 1971). Since then numeral sources of NMS have been
reported (see Miller and Fick 1997). Up to now, 11 nuclear male sterility
genes are published (Pérez-Vich et al. 2005; Cheng et al. 2006). MS6 , MS7 ,
MS9 , MS10 , and MS11 have been placed on the genetic map of sunflower.