Early hybridization Universally referred to as the staff of life, wheat’s cultivation has allowed civilization to shift from a hunter-gatherer to agrarian lifestyle by supporting the congregation of enormous, concentrated populations (Brown et al.
, 2016; Jones, 2016; Sayer, 2013; Sofi, 2013). Triticum monococcum (einkorn) was the original strand of wheat, commonly referred to as the ancient wheat. Einkorn was cultivated around 3300 BC in the Middle East and Eastern Europe; the strand was not cold-tolerant and had a total of 14 chromosomes–the simplest genetic code of all wheat species (Davis, 2015).Shortly after the cultivation of ancient wheat, a new species formed as the natural offspring of einkorn and Aegilops speltoides (goatgrass).
The genome combination of both the einkorn and goatgrass resulted in emmer: a wheat species consisting of 28 chromosomes. Einkorn and emmer became staple foods in the agrarian diet, as these two earliest strands of wheat were bred from highly nutritious grasses. Both, however, shared alleles for poor yield and no resistance to extreme temperature change. Consequently, early domesticators attempted to increase the yield of the crop by breeding emmer with high yielding, weather resistant grasses.
It was rapidly discovered that allopolyploidization would allow wheat to easily inherit the allele for high yield from its parent plants. Allopolyploidization, unique to wheat, refers to the cereal crops ability to accumulate the sum of both parent plants’ specific genomes, thus allowing feasible selective breeding for the addition of desirable traits (Farris, 2014). This was the start of early wheat hybridization: a movement to increase wheat yield and resistance with no attention paid to the inevitable nutritional consequences of the altered crop (Carvalho, 2006; Nadeem, 2010; Shiferaw, 2012).Triticum turgidum (emmer) was eventually bread with Aegilops tauschii (a diploid goatgrass species) to form Triticum aestivum–a 42 chromosome strand, closely resembling wheat consumed in the 21st century–along with hundreds of other new strands (Davis, 2015). As the population continued to thrive on these cereal grains, the need for new hybridized stands of wheat that possessed genomes that coded for augmented yield increased (Davis, 2015; Brown et al., 2016; Reynolds, 2005).