As a crop, maize was subjected to artificial selection during domestication [2], [3] and [4] with subsequent episodes of post-domestication selection or improvement [5] and innovative agronomic practices. Strong selection pressure directed at genes controlling traits of agronomic importance shapes genetic variation that is available to modern breeders as it affects genome-wide nucleotide diversity and patterns of linkage disequilibrium (LD) [6]. Thus, the variation can be optimized and the check details direction of recombination enhanced via evolutionary

analyses using genomics information to exploit the variation acted on by artificial selection [6]. Human selection of maize has largely focused on grain since its early domestication. Therefore, a number of genes associated with maize ears, including those for kernel color (c1 [7] and y1 [8]), and kernel composition (bt2 and su1 [9], su1 [10], sh2 [11]), were analyzed for the effects of their association with selection [3]. The maize P locus is involved in the synthesis of a red flavonoid pigment in cobs, in

the kernel pericarp, and in other floral tissues [12]. Gene P1, encoding a Myb transcription factor [13], [14] and [15], confers different color phenotypes on pericarp and cob glumes through different epigenetic alleles or forms [14], [15], [16], [17], [18] and [19]. A sharp probability peak (highest, P = 10− 17) in a mapping study was found to coincide with the known location of P1 (Fengler K, personal communication in reference [20]). QTL mapping based on a number of populations developed Ruxolitinib price by crossing two functional, but distinct, P alleles has identified a QTL in bin 1.03 [21]. It had also been an important model for gene expression regulation since the early days of modern genetics [22]. Other findings suggested that the P locus is a complex locus with different copy-number variants in a tandem repeat pattern and regulated by methylation

[12] and [13]. Candidate gene association was conducted to verify Liothyronine Sodium that P1 was associated with pericarp, cob, and silk pigmentation in 76 maize lines [23]. In addition, P1 was suggested to be tightly linked with a chromosomal region that is important for controlling yield in those source populations [24]. Later work demonstrated that selection for cob color had effects on several other traits including grain yield in different genetic backgrounds [25]. It was suggested that some maize color components were less preferred, by or more toxic, to caterpillars such as Helicoverpa zea (Boddie) and sap beetles such as Carpophilus lugubris [26], which are major pests of maize during kernel storage. All this information suggests that cob glume color might be a trait under selection or a result of selection during breeding and consumer preference during the post-domestication period.