Modelling root plasticity and response of narrow-leafed lupin to heterogeneous phosphorus supply

<p><strong>Background & Aims:</strong> Searching for root traits underpinning efficient nutrient acquisition has received increased attention in modern breeding programs aimed at improved crop productivity. Root models provide an opportunity to investigate root-soil interactions through representing the relationships between rooting traits and the non-uniform supply of soil resources. This study used simulation modelling to predict and identify phenotypic plasticity, root growth responses and phosphorus (P) use efficiency of contrasting <i>Lupinus angustifolius genotypes</i> to localised soil P in a glasshouse.</p> <p><strong>Methods:</strong> Two <i>L. angustifolius</i> genotypes with contrasting root systems were grown in cylindrical columns containing uniform soil with three P treatments (nil and 20 mg P kg⁻¹ either top-dressed or banded) in the glasshouse. Computer simulations were carried out with root architecture model ROOTMAP whichwas parameterized with root architectural data from an earlier published hydroponic phenotyping study.</p> <p><strong>Results:</strong> The experimental and simulated results showed that plants supplied with banded P had the largest root system and the greatest P-uptake efficiency. The P addition significantly stimulated root branching in the topsoil, whereas plants with nil P had relatively deeper roots. Genotype-dependent root growth plasticity in response to P supply was shown, with the greatest response to banded P.</p>