Carbon isotope discrimination as a means to evaluating drought resistance in barley, rice and cowpeas.

AUSTIN, R. B.; CRAUFURD, P. Q.; HALL, M. A.; ACEVEDO, E.; PINHEIRO, B. da S.; NGUCI, E. C. K.

Carbon isotope discrimination as a means to evaluating drought resistance in barley, rice and cowpeas.

Autores

Descripción

In all the crops studied there was variation among genotypes in carbon isotope discrimination (Δ). In trials of barley genotypes there were strong positive correlations between grain yield and Δ, though in trials which were irrigated or received abundant rainfall, this correlation was non-significant or negative. Some of the variation in yield and Δ was related to date of heading, as early varieties in stressed trials had highest yields and had high Δ. In an experiment with 8 early and 10 late flowering rice genotypes there were consistent positive correlations between yield and Δ in the early group, but in the late group the correlations tended to be negative. Among the early group the early genotypes were highest yielding, and may be presumed to have avoided the worst effects of drought and hence had higher Δ. In the late group, there was no correlation between yield and date of flowering. In one experiment with cowpeas, a weak positive correlation between grain yield and Δ was observed, but in a second trial, in an abnormally wet season, no such correlation was observed. In all three crops further work is needed before the usefulness of carbon isotope discrimination for screening for high yield in water-limited environments can be assessed.