Saving water to get ‘more crop per drop’ – A new phenotyping framework revealed wide plasticity in wheat

Abstract

ABSTRACT Improving transpiration efficiency (TE) offers a pathway to increase yield in drought-prone environments. This study examined genotypic variation in TE and its physiological determinants across diverse wheat lines. An initial experiment with six cultivars was expanded to 105 genetically-diverse genotypes evaluated under well-watered conditions and fluctuating vapour pressure deficit (VPD). Using a high-throughput lysimeter platform, transpiration rates were recorded every 10 minutes and normalised daily at low VPD to account for genotypic variations in canopy size. TE was strongly associated with reduced normalised transpiration rate at high VPD (TR norm-highVPD ), while no significant relationship was found with maximum photosynthetic capacity. High-TE lines achieved either greater biomass with similar water use or similar biomass with lower water use, reflecting a water-saving strategy under high evaporative demand. A complementary experiment under low VPD revealed limited genotypic variation in intrinsic TE, reinforcing the value of TR norm-highVPD as a screening trait. Consistent correlations between TE and TR norm-highVPD across experiments highlight the potential of TR norm-highVPD as a robust phenotyping target. Several high-TE lines outperformed modern cultivars, offering promising sources of novel alleles. These findings provide a scalable framework to identify drought-resilient genotypes and support breeding strategies to improve water productivity and achieve more crop per drop. HIGHLIGHT Wheat genotypes with reduced normalised transpiration rate under high evaporative demand achieved greater transpiration efficiency. A new automatised high-throughput phenotyping framework is proposed to assist drought-resilient breeding.

Plant phenotyping relevance

高スループットライシメータによる蒸散効率・正規化蒸散速度の取得とスクリーニング枠組みが研究の中心であり、育種向け表現型測定法を提案・評価している。

Code and data availability

The supplied blocks describe wheat lysimeter phenotyping experiments and R-based analyses but contain no data availability statement, public dataset deposit, or author code repository URL. The only URL present is a cited reference DOI (Zadoks 1974), which is unrelated prior work.

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