Development of Broomrope resistance in Sunflower

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.