Cotton is one of the most significant fiber commodities in the world, and it has significant economic and monetary returns that significantly impact the national income of cotton-producing countries in large quantities and across large areas. There are about 50 types of cotton in the world, but only four types of these fifty types represent the spread of cotton and its cultivation in the world. We find that American cotton or Upland cotton (Gossypium hirsutum L.) is spread in an area of up to about 90% of the total areas planted with cotton in the world, which amounts to 2.5% of the cultivated area on the globe. Then comes Indian cotton and African cotton (Gossypium herbaceum L.) and Gossypium arboreum L.), which together represent about 7% of the total cotton cultivated area in the world. Then comes Egyptian cotton (Gossypium barbadense L.), which represents the best and softest types of cotton in the world and represents approximately 3% of the total cotton cultivated area in the world. We find that one of the most important features of American cotton is that it is tolerant to different weather conditions and tolerant to temperatures, whether high or low temperatures and contains genetic genes specific to drought tolerance and salinity tolerance, whether soil salinity or soil salinity. In addition, the presence of a group of descriptive characteristics and the possibility of applying genetic engineering techniques to produce insect-resistant plants, represent the economic dilemma of cotton production in the world. Therefore, its spread over a very wide range of latitudes and over a wide range of temperatures, whether low temperatures or high temperatures and its ability to spread over a wide range of lands is what creates a place for it to spread as the largest cotton cultivated area in the world. This chapter elucidates the properties and potential applications of fibers obtained from upland cotton species leaves, the techniques for extracting fibers, germplasm biodiversity and conservation, the goals and stages of beetroot breeding initiatives, and traditional breeding methodologies. It also covers contemporary methods of plant breeding, including genetic alteration and marker-assisted selection.