Root-trait variation in F3 wheat populations under three water-regimes

Context Root traits may support early-generation wheat selection, but valid interpretation requires experimental independence and adequate sampling of segregating material. Aims We quantified phenotypic variation in total root length (TRL), mean root diameter (MRD), root dry mass (RDM) and specific root length (SRL) among seven F3 populations and two check cultivars separately within control, −0.3 MPa and −1.0 MPa sectors. Methods Each regime occupied one physically separate greenhouse sector. Within each sector, nine entries were randomised in four complete replications and harvested at anthesis. Because water regime was not independently replicated, across-sector patterns were descriptive and formal inference was restricted to entry comparisons within sectors. Key results Entries differed for MRD in all sectors, for RDM at −0.3 MPa, and for SRL at −0.3 and −1.0 MPa; TRL did not differ significantly within any sector. These estimates describe small samples of four selected F3 plants per population and sector. Conclusions MRD provided the most consistent entry differentiation, while RDM and SRL supplied complementary information within specific sectors. Implications The results identify candidate root phenotypes for independently replicated validation with larger population samples; they do not demonstrate causal regime effects, stable population rankings or drought tolerance.