This group of gene classes describes the accumulated research into the basis of the variation in glume color phenotypes which spans red, black, brown and grey colors.

Glume color is an important trait to characterize wheat cultivars and has been studied for many years using conventional techniques (e.g. Sikka et al., 1961; Zeven, 1983; Efremova et al., 1998; Khlestkina et al., 2006; 2009). Recent GWAS analysis of a a global diversity panel of 267 spelt accessions by Abrouk et al., (2021) has concluded that the gene Rg-B1 encodes a putative R2R3-MYB-like transcription factor, TraesCS1B02G005200 .

MYB transcription factors have been identified as major determinants of grain, kernel, fruit, and flower pigmentation in plants by regulating the biosynthesis of flavonoids. In the reference genome wheat cultivar ‘Chinese Spring’, which has white glumes, a 8.1 kb Mutator-like transposable element (MULE) is inserted in the second intron of the Rg-B1 gene (TraesCS1B02G005200).

Red glumes Gene Class

• Rg1 (Triticum) gene
• Rg2 (Triticum) gene
• Rg3 (Triticum) gene
• Rg-A1 (Triticum) gene
• Rg-A1a (Triticum) allele
• Rg-A1b (Triticum) allele
• Rg-A1c (Triticum) allele
• Rg-A1d (Triticum) allele
• Rg-B1 (Triticum) gene
  • Rg-B1a (Triticum) allele
  • Rg-B1b (Triticum) allele
• Rg-D1 (Triticum) gene
  • Rg-D1a (Triticum) allele
  • Rg-D1b (Triticum) allele
  • Rg-D1c (Triticum) allele

• QRg.ipk-1D QTL

Black glumes Gene Class

• Bg (Triticum) gene
• bg (Triticum) allele
• Bga (Triticum) allele
• Bgb (Triticum) allele

Pseudo-black chaff Gene Class

• Pbc (Triticum) gene

Chocolate chaff Gene Class

• cc (Triticum) gene

Inhibitor of glume pigment Gene Class