Carbon Isotope Discrimination: A Gateway to Smarter Water Use and Drought-resilient Cereals
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Date
2026-06-09
Journal Title
Journal ISSN
Volume Title
Publisher
Hill Publishing
Abstract
Carbon isotope discrimination (Δ¹³C) is widely used as an integrative physiological trait for assessing intrinsic water use efficiency (iWUE) in cereals under water
limited conditions. This review synthesizes the physiological basis linking Δ¹³C to iWUE through intercellular-to-atmospheric CO₂ ratios (cᵢ/cₐ), emphasizing sto
matal conductance, photosynthetic capacity, and genotype × environment interactions. Environmental drivers, including drought, temperature, vapor pressure defi
cit, and atmospheric CO₂, are evaluated alongside differences between C₃ and C₄ cereals. Analytical approaches such as isotope ratio mass spectrometry (IRMS),
near-infrared spectroscopy (NIRS), and laser-based methods are compared in terms of precision and scalability. Evidence shows a strong inverse relationship between Δ¹³C and iWUE in C₃ species, while C₄ responses are weaker due to CO₂ concentrating mechanisms. Despite limitations related to environmental sensitivity and inconsistent trait-yield relationships, integrating Δ¹³C with complementary traits, multi-environment testing, and genomic tools enhances its application in breeding. Δ¹³C remains a valuable tool for developing drought-resilient cereal ideotypes.
Description
Keywords
Wheat, drought tolerance, C₃ photosynthesis, crop improvement, climate resilience, carbon isotopic signatures
Citation
Mafirakurewa, T., Mathema, N. and Mutanda, M. (2026) ‘Carbon Isotope Discrimination: A Gateway to Smarter Water Use and Drought-resilient Cereals’, International Journal of Food Science and Agriculture, 10(2), pp. 131–145 DOI: 10.26855/ijfsa.2026.06.003