ORIGINAL RESEARCH article
Front. Plant Sci.
Sec. Crop and Product Physiology
This article is part of the Research TopicWater Use Efficiency (WUE): Enhancing Crop Resilience Using Agronomic and Genetic Strategies Under Abiotic Stress ConditionsView all articles
Divergent physiological strategies distinguish tolerant and plastic genotypes in elite Australian lines under limited irrigation
Provisionally accepted
- 1Swinburne University of Technology, Hawthorn, Australia
- 2Leibniz-Institut fur Pflanzengenetik und Kulturpflanzenforschung (IPK), Seeland, Germany
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Water scarcity threatens global rice production, necessitating identification of genotypes with improved water use efficiency (WUE) whilst maintaining productivity. Previous drought studies typically imposed severe stress conditions that compromised yield and quality, creating a knowledge gap regarding rice responses to moderate water limitation during vegetative growth. Here we show that 19 temperate japonica and 2 indica rice genotypes employ two distinct water conservation strategies under controlled limited water conditions (60–65% field capacity): inherent physiological tolerance versus adaptive phenotypic plasticity. We evaluated rice varieties under ponded and limited water treatments, integrating stomatal traits, chlorophyll fluorescence parameters, leaf carbon isotope composition (δ¹³C), and surface properties quantified via scanning electron microscopy and ATR-FTIR spectroscopy. Inherently tolerant genotypes (Moroberekan, Harra, Sherpa, Reiziq, Langi) maintained stable photosynthetic performance through constitutively lower stomatal conductance and enhanced cuticular wax deposition. Conversely, adaptive genotypes (Pokkali, Doongara, Namaga, Amaroo) exhibited pronounced physiological plasticity under water limitation. Notably, LW treatment induced significant enlargement of leaf surface papillae positioned over stomatal complexes, suggesting a potential structural mechanism contributing to reduced transpirational water loss. This represents a previously under-recognised adaptation in smooth-leaf Australian germplasm lacking protective trichomes. Mixed-effects modelling confirmed that photochemical traits and water-use traits responded most strongly to treatment, while reproductive and yield-related measurements indicated no major penalty under limited water. Carbon isotope discrimination (δ¹³C) validated superior intrinsic WUE in top-performing varieties. These complementary strategies provide multiple pathways for breeding water-efficient rice adapted to Australian temperate production systems under moderate water limitation without substantial yield loss.
Keywords: cuticular and epicuticular wax, drought adaptation, glabrous leaf phenotype, leaf surface hydrophobicity, Oryza sativa, papillae morphology, photosystem II efficiency
Received: 04 Dec 2025; Accepted: 09 Jan 2026.
Copyright: © 2026 Fernando, Kuhlmann, Adams and Butardo. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Vito M. Butardo
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