Field phenomics reveals genetic variation for transpiration response to vapor pressure deficit in sorghum

Abstract

Drought adaptation for water-limited environments relies on traits that optimize plant water budgets. Limited transpiration (LT) reduces water demand under high vapor pressure deficit (VPD) (i.e., dry air condition), conserving water for efficient use during the reproductive stage. Although studies in controlled environments report genetic variation for LT, confirming its replicability in field conditions is critical for developing water-resilient crops. Here we test the existence of genetic variation for LT in sorghum in field trials and whether canopy temperature (TC) is a surrogate method to discriminate this trait. We phenotyped transpiration response to VPD (TR-VPD) via stomatal conductance (gs), canopy temperature (TC) from fixed IRT sensors (TCirt), and unoccupied aerial system thermal imagery (TCimg) in 11 genotypes. Replicability among phenomic approaches for three genotypes revealed genetic variability for TR-VPD. Genotypes BTx2752 and SC979 carry the LT trait, while genotype DKS54-00 has the non-LT trait. TC can determine differences in TR-VPD. However, the broad sense heritability (H2) and correlations suggest that canopy architecture and stand count hampers TCirt and TCimg measurement. Unexpectedly, observations of gs and VPD showed non-linear patterns for genotypes with LT and non-LT traits. Our findings provide further insights into the genetics of plant water dynamics.

Plant phenotyping relevance

圃場での蒸散応答という植物生理形質を、固定式赤外線センサーとUAS熱画像で測定し、手法間の再現性と代理指標としての妥当性を評価しており、フェノタイピング手法が中心である。

Code and data availability

The supplied blocks describe field phenotyping (porometer gs, IRT and UAV thermal imaging) and R-based regression analyses, but contain no data availability statement, no deposited phenotype datasets or thermal images, and no author code repository or public URL. The only URL mentioned in methods (PRISM climate data)is

No evidence-backed public reproduction asset is currently recorded.