Genomic regions and underlying candidate genes associated with coleoptile length under deep sowing conditions in a wheat RIL population

Longer coleoptile is a desirable trait in wheat for sowing under drought stress environments with moisture availability in the deeper layers of the soil. In the present study, WL711/C306 wheat RIL population and the parents were phenotyped for coleoptile length under deep sowing conditions in the field and plant growth chamber. C306, a tall traditional cultivar had longer coleoptile compared to the semi dwarf parent WL711 carrying Rht-B1b gene. The RIL population showed considerable variation, normal distribution and transgressive segregation for coleoptile length under field and controlled environment conditions. The genetic linkage map of WL711/C306 RIL population was constructed comprising of 346 markers. The total map distance was 4,526.8 cM with an averaged interval of 12.9 cM between the adjacent markers. Major novel consistent QTLs for coleoptile length were identified on 4BS, co-located with the Rht-B1b gene and on 3BS. Also major QTL was identified on chromosome 3BL for coleoptile length explaining up to 12.4 % of phenotypic variation. On comparison with the rice (Oryza sativa L.) genomic DNA sequences syntenic to wheat chromosome 4BS and 3BS, two candidate genes were identified namely gibberellin C-20 oxidase 1 and alpha-Expansin. These genes play a role in cell wall expansion in the young expanding tissue in the coleoptile. QTLs qCL.4B.1 and qCL.3B.1 emerge to be important for coleoptile length in the WL711/C306 RIL population suggesting their potential value for use in marker assisted selection after validation for longer coleoptile length and improved establishment.