Genetic variation in specific root length in Scandinavian wheat and barley accessions

Summary

Specific root length (SRL, m root g-1 root dry matter) was studied in a broad selection of old and presently grown accessions of spring wheat and barley from Norway and Sweden, at sub-optimal phosphorus conditions in nutrient solution and soil. The results indicated that genotype did not have a significant effect on SRL. A close relationship between root length (RL) and root weight (RW) was found, and more than 70% of the variation in root lengths was explained by root weights of representative and homogenous root samples. In nutrient solution, the relationship between RL and RW was described by the regression equations RL = 0.32RW – 0.19 (R2 = 0.74) for wheat and RL = 0.20RW + 0.73 (R2 = 0.56) for barley. In the soil experiment, the relationships between RL and RW were described by the equations RL = 0.16RW + 0.50 (R2 = 0.77) for wheat and RL = 0.15RW + 0.95 (R2 = 0.67) for barley. Hence, in screenings of a large number of cereal genotypes, the root length (y-axis) may be estimated with good accuracy by records of root weight (x-axis) and an appropriate regression equation.