ABSTRACT
Wheat (Triticum aestivum L.) is grown in a wide range of environments around the world and has the broadest adaptation of all cereal crop species (Briggle and Curtis 1987). Although the majority of wheat is produced in the range of 25-50° latitude, wheat production has expanded to the lower latitude (15°) as a cool season crop and to the higher latitude (60°N) as a warm season crop (Musick and Porter 1990). In addition, wheat is the number one food grain consumed directly by humans and provides more nourishment for people than any other food source. Wheat grains are the most important source of carbohydrates in the countries of temperate zone (Briggle and Curtis 1987). Therefore, wheat production plays a critical role in the world economy and food security.
