Increasing root penetration into a different environment is more
important than improving rooting depth
Abstract
Deep rooting is often thought as a promising phenotype for resource
extraction, but on soils with constraints, desired rooting depth was
rarely observed. We hypothesised that if the genetic effect on root
growth and rooting depth were separated from other effects, the
determinants of root growth and rooting depth could be quantified. The
conventional core-breaking method was used to measure root growth of
wheat at two sites in two successive years under rain fed conditions.
The Bayesian hierarchical nonlinear mixed models (HNLMMs) were employed
to estimate root distribution, heritability and rooting depth. We found
that root penetration from the non-sodic top to the sodic subsoil was
most critical in determining rooting depth. Our study indicates that
focusing on root-soil interaction at the transition layer where soil
constraints start to emerge would lead to a more effective solution to
develop resilient roots. Our work not only serves as a guide for
selecting genotypes in pot trials, but also provides a theoretical
support to breed advance crops with better soil adaptation.