
TY  - JOUR
A1  - Dingkuhn, M 
A1  - Farquhar, GD 
A1  - De, Datta SK 
A1  - O'Toole, JC 
A1  - Datta, SKde 
T1  - Discrimination of <sup>13</sup>C among upland rices having different water use efficiencies
JF  - Australian Journal of Agricultural Research
JO  - Aust. J.  Agric. Res.
Y1  - 1991
VL  - 42
IS  - 7
SP  - 1123
EP  - 1131
KW  - 
UR  - https://doi.org/10.1071/AR9911123 
N2  - Discrimination of stable carbon isotopes in leaves is physiologically linked to water-use efficiency. Twenty-eight contrasting rice (Oryza sativa L.) cultivars were grown in the Philippines as upland rice under continuous, mild water stress. In situ measurements of leaf level water-use efficiency (WUE), net photosynthesis, conductance, water potential and leaf rolling were reported previously. The present study used leaf samples from the same experiment to determine, by means of a mass spectrometer, the carbon isotope discrimination (-) and total C and N content. Among rice cultivars, - ranged from 19.8 to 21.5960, with japonica types having the lowest mean -, aus types, the greatest, and indica types, intermediate-the opposite pattern to that observed for WUE. Carbon isotope discrimination was negatively correlated with WUE across all cultivars (P < 0.001) and within japonica (P < 0 -01) and aus (P < 0.05) groups, but not among indica rices. No correlation was observed between - and any other measured variable. Varietal differences in - and WUE were not related to leaf N content or stomata1 conductance. High WUE was associated with high leaf C content (P < 0.01), with aus cultivars having the lowest mean WUE and C content among the genetic groups. We conclude that even under variable field conditions, analysis of foliar - is a potential tool to identify water-use efficient rice genotypes. 
ER  -

