Mapping the glaucousness suppressor Iw1 from wild emmer wheat “PI 481521”

Many species of Triticeae display a glaucous phenotype. In wheat, glaucousness/waxiness on spikes, leaves and shoots is controlled by wax production genes (W loci) and epistatic inhibitors (Iw loci). In this study, a suppressor of glaucousness from wild emmer wheat (Triticum turgidum ssp. dicoccoides) accession “PI 481521” was investigated in a pair of durum (T. turgidum ssp. durum cv. “Langdon”, LDN)—wild emmer wheat chromosome substitution lines, LDN and “LDN_DIC521-2B”. Genetic analysis revealed that the non-glaucous phenotype of LDN_DIC521-2B was controlled by the dominant glaucous suppressor Iw1 on the short arm of chromosome 2B. In total, 371 2B-specific marker differences were identified between LDN and LDN_DIC521-2B. The location of the Iw1 gene was mapped using an F₂ population that stemmed from LDN and LDN_DIC521-2B, generating a partial linkage map that included 19 simple sequence repeats (SSR) and ten gene-based markers. On the current map, the Iw1 gene was located within the Xgwm614–BE498111 interval, and cosegregated with BQ788707, CD893659, CD927782, CD938589, and Xbarc35. Mapping of Iw1 in LDN_DIC521-2B, a publically accessible and widely distributed line, will provide valuable information for marker-assisted selection of the agronomically important trait of glaucousness.