Sunflower (Helianthus annuus L.) is one of
the four important sources of edible oil in the
world. Fungal diseases are considered as major
constraints for its seed yield and quality. Basal
stem rot resulted by Sclerotinia sclerotiorum (Lib.)
de Bary fungus, is known as a serious disease on
oily sunflower, worldwide. In this project, genomic
region linked with partial resistance to basal stem
rot disease was identified using a population of
recombinant inbred lines (RILs) created from the
hybridization between PAC2 (♀) and RHA266
(♂) lines. Nine phenotypic characters related
to disease resistance including PN4D, PN8D,
PN12D, NCW100S, CW100S, NCPY, CPY,
DP100S and DPY were measured under artificial
infection in the field conditions. Newly developed
genetic linkage map of sunflower was used for
detecting and mapping QTLs. The linkage map
includes 210 SSR and 11 SNP markers distributed
in 17 groups. The analysis was carried out using
composite interval mapping (CIM) procedure.
High coefficient of variation (CV) was detected
for those studied characters that reveal high
genetic variability for susceptibility to disease in
the studied sunflower RIL population. Totally, 56
putative QTLs were identified for the studied nine
quantitative characters. The number of QTLs for
each character ranged from 1 to 9, explaining 0.91
to 80.75% of phenotypic variation (R2). Additive
effect sign was positive for 17 QTLs, suggesting
that the promising allele has been transmitted
from male parent (RHA266). In this project, major
QTLs (LOD≥2.5 and R2≥10%) were identified for
all of the studied characters, exceptifor NCW100S
and CW100S characters. The major QTLs are
important for running marker-aided selection
(MAS) in resistant breeding programs.