## 1 Introduction  
The continuous growth of the world population highlights one of the most delicate problems of our century: providing food for mankind. Wheat is one of the most important cereal crops in the world, originally cultivated approximately 12,000 years ago in the Fertile Crescent [1]. In a course of history, about 8000 years ago, wheat became the main food source of most communities, so today it is widely cultivated around the world, covering 17% of the world's cultivated area and feeding 40% of the world's population [2]. Nowadays, wheat is a crop with multiple and diverse genetic resources available because of the general evolution of people and particularly the evolution of the agricultural segment, as there are currently many species of wheat cultivated by thousands of populations all over the world. Known functional genetic studies regarding the wheat crop are mostly focused on identifying natural variations, therefore contributing to the assembly and enrichment of wheat genetic stock [3, 4]. By implementing different breeding programs, cultivators aim to obtain wheat crops with an increased agronomic performance, characterized by an improved yield, better quality and increased resistance to disease [4]. Sustainable wheat cultivation involves the conservation of species and the evaluation and characterization of genetic resources, as genetic diversity can nowadays be considered the key for many agricultural challenges. Romania, due to its geographical location and temperate-continental climate, offers favorable conditions for wheat cultivation. Romanian wheat culture has been known since ancient times, from the Upper Neolithic and the Bronze Age [5]. Due to the food-friendly chemical composition, consisting of proteins, carbohydrates, lipids, minerals and vitamins but also its bread-making properties, wheat is used in human nutrition in the form of bread, pasta, biscuits and pastries [6]. As these products are very common for most countries globally, wheat occupies the first place in worldwide cereal production. The main wheat producers are considered to be European Union countries, China, India, Russia, USA, Canada, Ukraine and Pakistan [7]. In the EU, Romania achieved the 4 th rank in wheat production after France, Germany and Poland [6], being one of the most important producers from Europe and the world. Among cereals, it occupies one of the largest areas of the total arable land, being of great economic importance in Romania and contributing to the country's food security [8]. In 2000, the wheat production in Romania was about 4.4 million tons per year. In 2020, this amount increased to 52.27%, and it is estimated to grow even more by 2030, up to 138%, which is 16 million tons of wheat annually [9]. The milling and bakery sectors depend on wheat production and grain quality. Romanian wheat varieties, such as Izvor, Glosa, Miranda, Pitar, Putna and Ariesan, must be adapted to the climatic conditions and soils on which they are cultivated to produce grains of as high of a quality as possible [10]. In order to describe the genetic diversity within and between populations or groups of individuals, molecular markers are used. Molecular markers are capable of detecting high levels of polymorphism [11]. These markers are provided by the wheat seed protein complex, which is mostly associated with the bakery quality of a product [12]. Gliadin, as an important protein compound, plays a primordial role in creating the gluten network, which is decisive in terms of dough rheological properties, especially when it comes to its elasticity and viscosity [13]. Gliadin is mainly responsible for dough viscosity, whereas glutenin, another important gluten protein, is responsible for dough elasticity [14]. Although there are other grains that contain gluten-type proteins, wheat is the only grain that can form dough when mixed. Chemically, wheat flour contains gluten proteins in proportions of 75-85% of the total protein content and there are also more proteins in the wheat endosperm [15].