Carbon isotope discrimination and grain yield for three bread wheat germplasm groups grown at different levels of water stress uri icon

abstract

  • Carbon isotope discrimination (Delta), yield and other characters were determined for 75 spring bread wheat cultivars and advanced breeding lines in which water availability was varied using a line-source irrigation system. The experiment was carried out in 1989/90 at CIMMYT-CIANO, Cd. Obregon, in northwest Mexico. Forty of the cultivars and advanced breeding lines came from CIMMYT-Mexico, twenty from ICARDA-Syria, and fifteen from CIMMYT's International Drought Trial (IDT). Considering all materials together, grain yield and Delta were markedly reduced by drought (yield declined from 4560 to 1090 kg ha(-1), Delta from 16.9 to 14.0 parts per thousand, from least to most stressed, respectively). For each group of lines, grain yield was positively correlated with Delta in both the most stressed and least stressed parts of the trial (except for the CIMMYT lines under low stress where the correlation was nonsignificant). In addition, high yield under stress was associated with an early maturity score and with less reduction in mature plant height, Delta may be potentially used to augment selection for high yield based on yield itself, in both low- and high-stressed environments, In the latter environment, early maturity and minimal reduction in plant height should also be considered in a selection program especially under conditions of mid-season to terminal drought and/or heat stress.

publication date

  • 1995
  • 1995