Coupled functional physiological phenotyping and simulation model to estimate dynamic water use efficiency and infer transpiration sensitivity traits

Abstract

As agricultural drought becomes more frequent worldwide, it is essential to improve crop productivity whilst reducing the water consumption to achieve a sustainable production. Plant transpiration and water use efficiency (WUE) collectively determine the yield performance, yet it is challenging to balance the two in breeding programs due to still insufficient mechanistic understanding of the traits. Here we developed a method of quantifying the genotype-specific traits reflecting sensitivity of transpiration to radiation (Rad) and vapor pressure deficit (VPD) under evolving developmental stage and water availability (STr-Rad and STr-VPD). Our method takes advantages of the state-of-the-art functional physiological phenotyping (FPP) and the principle of inversely using simulation models. We revealed the genotypic difference of STr-Rad and STr-VPD in three watermelon accessions, the dramatic change in each of them across the treatment phases, and the quantitative impacts of them on dynamic WUE patterns. Based on our findings, a general principle for transpiration ideotype design is proposed, which highlights the benefits of lowering STr-VPD to increase WUE and increasing STr-Rad to offset the decline of Tr. FPP-enabled phenomic selection will help screen for elite crops lines with desired transpiration sensitivities.