A novel P indicator to evaluate bread wheat (Triticum aestivum L.) genotypes to identify tolerance to phosphorus deficiency based on two distinct root phenotyping platforms

Background and aims: Phosphorus is a crucial micronutrient for plant growth that, despite its abundance in soils, is often a limiting factor in agricultural productivity, particularly for cereals such as wheat. In this study, the response of different wheat genotypes to two different levels of phosphorus (P) was evaluated on a large trial encompassing 26 genotypes using two distinct root phenotyping platforms, ALSIA and 4PMI. Methods: Rhizotubes allowed non-invasive root phenotyping, revealing significant genotypic effects on biomass production and root system traits. Phosphorus acquisition and use efficiency of the wheat genotypes were estimated by using five different metrics. Key results: A synthetic indicator for agronomic relevance integrating the efficiency metrics has been established. Under optimal conditions, after 96 days, P acquisition efficiency (PAE) was inversely correlated with P utilization efficiency (PUE), suggesting an acquisition-use tradeoff. Conversely, under low P conditions, both after 27 and 96 days PAE and PUE showed moderate positive correlations, indicating adaptive coordination to improve P utilisation under scarcity. Conclusions: Overall, our findings highlighted the importance of root-target strategies in phosphorus efficiency in wheat, providing insights for breeders to enhance P tolerance in wheat.