Wheat (Triticum aestivum L.) "King of the cereals" is the staple food of people in many countries. It is the main rabi crop of Pakistan and India and ranks second after rice in Pkistan. It is used both as food for human consumption and feed for animals. It plays pivotal role in human nutrition containing carbohydrates, proteins, inorganic ions and vitamins. So, there is a dire need to develop genotypes having better yield potential per unit area. This will be achieved only by exploring maximum genetic potential from available germplasm of wheat. The origin of the cultivated wheat and its uses by mankind antedated the earliest recorded history. Wheat is believed to have been one of the first plants to be domesticated and cultivated by the humans, beginning possibly more than 15 thousands years ago with the seed gathered from wild grass ancestors of present day wheat species. The evolution of wheat has been the subject of great research during previous century. The basic evolutionary step was hybridization between the species.