Using carbon isotope discrimination to select maize (Zea mays L.) inbred lines and hybrids for drought tolerance uri icon

abstract

  • In C-3 plants, carbon isotope discrimination (A) shows large environmental and genetic variations and is linearly positively related to C-i/C-a, the internal to atmospheric CO2 ratio. It has been proven to be an accurate predictor of yield under drought conditions. In C-4 crops, information concerning A variation in different organs of the plant and its possible association with biomass or grain yield is still scarce. In the present study, A was first analyzed at flowering, under drought and well-watered conditions, in different organs of maize (Zea mays L.) inbred lines differing for drought tolerance. Leaf A was higher than ear and silk A. Drought stress significantly increased. in all organs. Under drought, tolerant inbred lines showed significantly higher A than susceptible ones. There was a significant positive correlation between leaf, ear and silk A, and ear dry weight at flowering, a trait closely associated to grain yield. Carbon isotope discrimination was then analyzed at flowering in leaves of a set of drought tolerant maize hybrids and checks. Drought tolerant hybrids had significantly higher grain yield and Delta than the used checks. No correlation was found, however, between A and grain yield within tolerant hybrids. The use of A appears consequently accurate for a first screening of lines or hybrids highly contrasting for drought tolerance, but not for a more advanced selection among tolerant hybrids. More studies are needed in maize and other C4 crops to establish the causes of A variation and precise which organ sampled and time of sampling may allow the better precision in the screening process. (c) 2007 Published by Elsevier Ireland Ltd.

publication date

  • 2007
  • 2007