MOLECULAR MARKER BASED COMPARISION OF DROUGHT TOLERANT AND SENSITIVE TURKISH SUNFLOWER (HELIANTHUS ANNUS L.) CULTIVARS
Authors: Şahin Rabia Vildan , Halász Júlia 
Published: February 2025

Helianthus annuus L. is the second most notable oilseed crop all around the world, after soybean, and comes from temperate North America. Sunflowers use for not only human consumption it uses also for many purposes. Morphological, geographical, molecular, and archaeological data indicate that sunflowers used as food, medicine, body painting in rituals, bioenergy and dye. Sunflower is a self-fertilize plant and it needs to pollen activity and honey bee for fertilization. There are some objectives in terms of sunflower breeding. These are drought resistance, resistance to disease and pets, breeding for self-fertile lines and branching shape. The pioneering sunflower breeding study was belonged to develop varieties with increased oil content. This was followed by the development of cytoplasmic male sterility (CMS) and haploid induction methods. In order to produce new cultivars with classical breeding methods is time consuming. To reduce this period uses double haploid technology and molecular marker-based technology. Molecular markers have been employed in a wide range of fields, including genetic mapping, paternity testing, identification of mutant genes related to hereditary diseases, cultivar identification, marker-assisted crop breeding, population history, epidemiology, food safety, and population studies. Among these, the start codon targeted (SCoT) marker has gained popularity for its ability to target a specific region around the ATG start codon, which is conserved across all plant species. SCoT markers are considered useful tools for studying genetic diversity in various plant species due to their simplicity, cost-effectiveness, high polymorphism, reproducibility, and time-saving attributes. Drought is defined as geographic location, amount, and time of precipitation. Also, it is defined as a shortage of water availability sufficient to cause a loss in yield or a period of no rainfall or irrigation that results in insufficient soil moisture leading to reduced crop growth and yield. Sunflower is one of the plants that needs a high amount of water during the development period. Studies of sunflower mainly focuses on drought response. This study aims to compare drought tolerant and sensitive Turkish cultivars using the SCoT marker system to find a linked DNA region that could be responsible for the tolerance. This research conducted with five common sunflower (Helianthus annus L.) genotypes that from three of them was drought tolerant, two of them was drought sensitive genotypes. The DNA of each sample was isolated from fresh leaves using the DNeasy Plant Mini Kit. Altogether 25 primers were tested and 13 SCoT primers gave enough polymorphism and PCR amplification was performed in a 2720 thermocycler. DNA bands were visualized by UV illumination using a gel document system (Bio-Rad). The approximate fragment size was compared with the GeneRuler™ 1 kb DNA ladder (Thermo Fisher Scientific). Banding profiles generated by SCoT primers were compiled into a data binary matrix based on the presence or absence of the selected band. The dendrogram and principal component analysis (PCA) were conducted using Past 4.04 software. Altogether 25 primers were tested and 13 SCoT primers successfully amplified 3 droughts tolerant and 2 drought sensitive genotypes of Helianthus annus L. and 13 SCoT primers gave 100% amplification with polymorphism. The total number of bands from 13 SCoT primers was 161, with 125 bands showing polymorphism and the average percentage of polymorphic bands was 76.79%. The size range of bands was from 250-8000 bp. The total number of bands range from 4 to 27 an average of 12.38 bands, while the number of polymorphic bands varied from 2 to 21 an average of 9.61 bands per primer. Based on the similarity and difference matrices highest value was belonged to drought tolerant cultivar with name 8129R. On the other hand, drought sensitive genotypes 9718A and 97251A have shown closely related values. The PCA result supports the results of similarity and distance matrices, which shows that 9718A and 97251A are closely related. In conclusion, the SCoT marker can be used as an effective molecular marker in case of sunflower genetic diversity analysis. Especially, drought tolerant cultivars TUNCA and P64LL62 showed similar characteristics in terms of genetical background of drought tolerant