ARS | Publication request: CARBON ISOTOPE DISCRIMINATION AS A SELECTION CRITERION FOR RICE SALT TOLERANCE

Submitted to: Soil Science Society of America Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: September 1, 2001
Publication Date: October 1, 2001
Citation: Poss, J.A., Zeng, L., Grieve, C.M. 2001. Carbon isotope discrimination as a selection criterion for rice salt tolerance. Soil Science Society of America Annual Meeting, held in Charlotte, NC. Oct. 21-25, 2001. (CD-ROM).

Technical Abstract: Twelve greenhouse cultured rice cultivars were grown at two soil water salinities (0.9 and 8 dS/m). Carbon isotope discrimination ([Delta]) values were obtained from seedling tissues harvested at 25 and 46 days after planting. These seedling tissue [Delta] values were then compared with final seed yield components of plants grown to maturity. Flag leaf [Delta] values of two of the genotypes known to have the largest differences in salt tolerance were also compared to final harvest indices of remaining plants for these genotypes. Fractionation effects of salinity stress on [Delta] were significantly different among genotype groupings. Although differences in yield due to salinity stress were large, the absolute [Delta] value differences between control and salt-stressed rice were approximately 1 per mil or less. These differences in [Delta] values due to salinity do not appear to be related to carboxylation efficiencies or stomatal resistances to the degree predicted from estimates of [Delta] based the ratio of internal leaf CO2 (Ci) to ambient CO2 (Ca) from gas exchange surveys when assuming primary factors responsible for tissue [Delta] are diffusion of CO2 and fractionation during carboxylation. General agreement with leaf tissue [Delta] rankings and a final salt tolerance ranking based on grain yield were observed.