Effect of water stress on carbon isotope discrimination and Rubisco activity in bread and durum wheat genotypes

Abstract

Carbon isotope discrimination (CID) has been suggested as an indirect tool for selection of water use efficiency in wheat. This study evaluates the role of Rubisco activity in regulating carbon isotope discrimination (CID) and discriminate the response of durum (PDW-233) and bread (C-306, HD-2329) wheat genotypes for carbon isotope discrimination and Rubisco activity under induced water stress hydroponically created by using different concentrations of PEG. In C-306, a well known drought tolerant genotype, CID was positively correlated with Rubisco activity. In C-306 CID was positively correlated with both Rubisco activity (r = 0.588* at 5). A positive but not a strong correlation was observed between Rubisco activity and CID (r = 0.418) in durum type PDW-233. Although in HD-2329 the Rubisco activity (r = 0.303) was positively correlated with CID, the correlations were not significant. We show that carbon isotope discrimination technique is a potential tool for selection of lines with high Rubisco activity in the wheat breeding program. © Prof. H.S. Srivastava Foundation for Science and Society 2009.