Wheat crop plays an important role in the agricultural system of Pakistan. Grain yield in Pakistan is much less as compared to other wheat producing countries of the world. Various factors are considered responsible for better crop harvest. Among which high potential varieties offer a tremendous scope. Different varieties of cereal respond differently through agro climatic conditions of a particular area due to difference in their genetic makeup and physical life process [6]. Selection of improved and high yielding genotypes of different cereal having a wide range of adaptation to agro climatic condition is essential to increase the yield per hectare. Breeders are making continuous efforts to improve wheat yield and production in Pakistan. However, still there is big gap in the yield per acre of wheat as compared to some other developing countries. This can be achieved by the agronomic, cultural and the genetic improvement. The improvement to 30-50% in wheat yield has been achieved by the introduction of newly high yielding cultivar in the country [2]. In general breeding for tolerance to drought involves combining good yield potential in the absence of the stress and the selection of traits that provide drought stress tolerance [8]. In defining a strategy for wheat breeding under drought stress, [5] suggested simultaneous evaluation of the germplasm both under near optimum conditions (to utilize high heritability and identify genotypes with high yield potential) and stress conditions (to preserve alleles for drought tolerance). In the case of wheat, yield in extremely dry years are reduced as much as 81% [4].
The production of 1 kg of wheat grain under fully irrigated conditions requires about 1 to 2 m3 of irrigation water [7], while in rainfed areas it requires from 1 to 3 m3 of rainwater [9]. Drought is the most dangerous problem of Pakistan as wheat is grown in areas where artificial means of irrigation are either lacking or inadequate. Low yield of wheat in Khyber Pakhtunkhwa (KPK) is due to moisture stress during its growth period mainly because most of the areas in the province are rainfed. The solutions include the development of different irrigation systems which require huge expenses. The best option is to develop drought tolerant wheat genotypes. High yield potential varieties play a pivotal role in increasing per hectare yield under optimum growing season. Although many high yielding wheat varieties have been evolved and recommended for general cultivation in the past but their performance under farmer’s field is not up to the mark as these have lost their adaptability to environmental conditions [1]. The wheat occupies a central position in the farming system of Pakistan. However, farmers grow low yielding local cultivars, which are susceptible to diseases like rusts, smuts and lodging. The yield in such places is about 30 percent lower than national average [3]. Low yield of wheat may be attributed to poor soil fertility, lack of irrigation water, weeds infestation, use of old agronomic practices and varieties of low yield