Assessment of branching phenomenon in the female parental inbred line of hybrid sunflower (Helianthus annus L.) cv. Azargol

Maintenance of genetic purity of parents of hybrid is important in hybrid development and commercialization. Branching phenotype in maternal line of Azargol, an Iranian sunflower hybrid, is a challenging. This experiment was carried out to understand thae basis of this phenomenon, and included three phases. Genetic phase, all possible crosses between plants possessing one, two, and/or three heads (suspicious plants) were made during 2013 to 2015 in Seed and Plant Improvement Institute, Iran and their progenies were backcrossed to single-headed parent. Molecular phase, previously published branching-linked molecular markers were evaluated on individuals from the parents, original single –headed, and original multi head genotypes. Bioinformatics phase, presence of environmentally responsive cis-regulatory elements in the promoters of branching genes characterized in other plant species were investigated. Genetic analysis indicated that progenies of all crosses (239 indivudials) appeared to be single headed plants. Similar banding pattern was observed among suspicious plants and original single-headed lines, but differed from original multi head genotypes. At least one cis-regulatory elements responding to cold and drought stress were found in the promoters of branching genes in other plant species. Results of the three phases of this experiment revealed insufficient evidence to attribute the branching phenotype in the inbredline of interest to genetic factors.