Abstract:
Sunflower is an annual herb belonging to the genus Helianthus which comprises of genus of
65 species. It is a diploid plant having chromosome number 34 and genome size 2871-3189
Mbps. Due to its remarkable size and conspicuous showy flowers, it is cultivated for
ornamental purposes. Broomrape is considered as a holoparasitic plant having parasitic effect
on sunflower root system. The infected plants are smaller having abridged kernel/husk ratio
leading to the reductions in yield potentials dramatically. It has become a serious issue for
sunflower production worldwide. In this analysis, a populace of F9 RILs were established
from crossing established between PAC2 and RHA266 via single-seed descent approach. The
experiment was completely randomized with three replicates under broomrape conditions in
Hamadan, Karaj, and Urmia. The genomic DNA of RILs and their parents were extracted,
and QTL mapping, descriptive statistics and ANOVA were performed. Correlation‘s analysis
revealed that FSW was significantly correlated with NFS, CW, CD, LL, LW, and PDW.
There was also significant correlation between FSW with NI in Karaj, Urmia. ANOVA
disclosed a significant interaction between sunflower samples and three different regions for
all of the studied traits expect for days to flowering and days to maturity. The map position
and characteristics of QTLs associated with the studied traits in Hamadan, Urmia, and Karaj
the highest and lowest number of QTLs were found in Hamadan and Urmia respectively.
QTLs explained from 12% to 60% of the phenotypic variance of the traits (R2), and both
parental lines contributed to the expression of the different target traits. Overlapping QTLs
were found for different traits on several linkage groups. Further experiments revealed that
the highest number of QTLs with ten QTLs were detected for NL in all datasets followed by
FSW, NFS, and LW with eight QTLs. No QTL was detected for ESW in different locations.
QTL mapping is an extremely operative method for considering genetically complex forms of
plant disease resistance.
