In wheat, a QTL QTrl.saw-2D.2 associated with the total root length was identified, presumably containing genes closely related to root development. A mapping population of 184 recombinant inbred lines derived from the cross SY95-71 × CH7034 was used to map QTL for seedling root characteristics in hydroponic culture (HC) and in soil-filled pot (SP) methods. Four traits, including maximum root length (MRL), root number (RN), total length (TRL), and root diameter (RD) were measured and used in QTL analyses. A total of 33 QTL for the four root traits were detected, 17 QTLs for TRL, six for RN, seven for MRL, and three for RD. Seven QTL were detected in both HC and SP methods, which explained 7-18% phenotypic variation. One QTL QTrl.saw-2D.2 detected in both HC and SP methods was also validated in another population comprised of 215 diverse lines. This QTL is a novel QTL that explained the highest phenotypic variation 18% in all QTL identified in the present study. Based on candidate gene and comparative genomics analyses, the QTL QTrl.saw-2D.2 may contain genes closely related to root development in wheat (Triticum aestivum L.). The two candidate genes were proposed to explore in future studies.
Keywords: Drought tolerance coefficient; Quantitative trait locus; Stay green; Total root length; Yield components.