The QTL analysis demonstrated that conspecific weed-crop differentiation involved many genomic segments with multiple loci regulating natural variation for adaptation and competitiveness.
In addition, more QTL clusters detected in this research indicate that "a small number of chromosomal segments" (Bres-Patry et al. 2001) is insufficient to explain the conspecific weed-crop differentiation for adaptive or domestication-related traits.
The first and second crops only appear to have differentiated at independent times because the first crop's differentiation and developmental seasons are separated by low-temperature-induced winter dormant period.
Moreover, various chemical tests were used so far in identification and differentiation of crop varieties based on the colour differences generated in the aleurone layer when reacted with different chemical tests.
Although studies have shed light on specific aspects of C. lunatus pathogenicity such as induce-virulence variations on maize crop [ 41], virulence differentiation on maize crop [ 42], secretome weaponries on potato crop [ 43], and heat-dependent virulence on Lolium spp. [ 44], the nutritional evolution of C. lunatus is unresolved.
An increase in chromosome number, or polyploidization, is associated with a variety of biological changes including breeding of cereal crops and flowers, terminal differentiation of specialized cells such as megakaryocytes, cellular stress and oncogenic transformation.
As such it represents both a tractable and evolutionarily appropriate genetic model for teasing apart sex differentiation in this crop and its wild relatives (Liston et al. 2014).
This led Bomblies and Doebley (2006) to suggest that, in general, undesirable secondary effects associated with pleiotropic genes could limit selection for favourable 'domestication alleles' during early stages of the differentiation of a crop from its wild progenitor.
These genes were responsible for major morphology differentiation between cultivated crops and their progenitors, such as branch (tb1) and glume architecture (tga1) in maize [ 52, 53], seed size (fw2.
Although the suitability of land for crops differs widely (Elsheikh et al. 2013), differentiation of yield potential for specific crops and forest species is missing and should be the topic of future methodical refinement.
