Genome-wide association analysis of coleoptile length and interaction with plant height in durum wheat

Genotypes with longer coleoptiles can be sown in deep soil layers to reach the underground moisture needed for germination in dry areas. Developing new varieties with longer coleoptiles and shorter plant heights would be novel for wheat breeding and production. In this study, coleoptile lengths of a panel of durum wheat (Triticum turgidum ssp. durum) genotypes were determined, and 14,255 DArTseq (SNP and Silico-DArT) markers were used to identify coleoptile length-associated markers by genome-wide association study (GWAS). A wide genetic variation was accounted for both coleoptile length and plant height. The genetic relationships between coleoptile length and plant height were evaluated using plant height values from five different environments. Two environmentally stable MTAs were identified, one for coleoptile length (QCol.su.4BS) and one for plant height (QPh.su.4BS). These MTAs were located on the short arm of chromosome 4B, with LOD scores up to 12.00 and 17.00, respectively. A relatively high LD (r2 = 0.71) was accounted for between QCol.su.4BS and QPh.su.4BS. The LD block intervals of the MTAs overlapped with some genes with roles in plant growth and development. The functions of plausible candidate genes tell us that QCol.su.4BS may be controlling coleoptile length, whereas QPh.su.4BS may be regulating plant height. The combination of the two loci would be desirable. In conclusion, this study sheds light on the genetic control of coleoptile length and its relationship with plant height in durum wheat. Cultivars with longer coleoptiles perform better at emergence and seedling establishment.A diverse durum wheat panel was studied using GWAS analysis to evaluate coleoptile length and plant height.Two significant and stable genomic regions were identified for coleoptile length and plant height.These regions might enhance coleoptile length while reducing plant height.