Oxygen isotope enrichment (Delta 18O) reflects yield potential and drought resistance in maize
Material type: TextPublication details: 2009Description: p. 77Summary: Drought is the major factor constraining world maize (Zea mays L.) production. The increment in the summer dryness and the occurrence of extended dry periods (IPCC, 2008), expects to decrease crop productivity which would increase risk of famine. This is particularly evident in tropical areas where rain-fed maize is a staple food for millions of people. Thus, improving yield potential and drought adaptation are among the main targets in most maize-breeding programs. Measurement of stable isotopes in plant dry matter has proved a useful phenotypic tool for speeding up breeding advance in C3 crops. However, the situation in C4 crops is far from resolved, since their photosynthetic metabolism precludes (at least in maize) the use of carbon isotope discrimination. This work investigates the use of oxygen isotope enrichment (18O) as a new secondary trait for yield potential and drought resistance in maize. A set of tropical maize hybrids developed by CIMMYT was grown under three contrasting water regimes in field conditions. Water regimes clearly affected plant growth and yield. In accordance with the current theory, a decrease in water input was translated into large decreases in stomatal conductance and increases in leaf temperature together with concomitant 18O enrichment of plant matter (leaves and kernels). In addition, kernel 18O correlated negatively with grain yield under well-watered (WW) and intermediate water stress (IS) conditions, while it correlated positively under severe water stress conditions (SS). Therefore, genotypes showing lower kernel 18O under WW and IS had higher yields in these environments, while the opposite trend was found under SS conditions. This illustrates the usefulness of 18O for selecting the genotypes best suited to differing water conditions.Browsing CIMMYT Knowledge Center: John Woolston Library shelves, Collection: CIMMYT Staff Publications Collection Close shelf browser (Hides shelf browser)
Abstract only
Drought is the major factor constraining world maize (Zea mays L.) production. The increment in the summer dryness and the occurrence of extended dry periods (IPCC, 2008), expects to decrease crop productivity which would increase risk of famine. This is particularly evident in tropical areas where rain-fed maize is a staple food for millions of people. Thus, improving yield potential and drought adaptation are among the main targets in most maize-breeding programs. Measurement of stable isotopes in plant dry matter has proved a useful phenotypic tool for speeding up breeding advance in C3 crops. However, the situation in C4 crops is far from resolved, since their photosynthetic metabolism precludes (at least in maize) the use of carbon isotope discrimination. This work investigates the use of oxygen isotope enrichment (18O) as a new secondary trait for yield potential and drought resistance in maize. A set of tropical maize hybrids developed by CIMMYT was grown under three contrasting water regimes in field conditions. Water regimes clearly affected plant growth and yield. In accordance with the current theory, a decrease in water input was translated into large decreases in stomatal conductance and increases in leaf temperature together with concomitant 18O enrichment of plant matter (leaves and kernels). In addition, kernel 18O correlated negatively with grain yield under well-watered (WW) and intermediate water stress (IS) conditions, while it correlated positively under severe water stress conditions (SS). Therefore, genotypes showing lower kernel 18O under WW and IS had higher yields in these environments, while the opposite trend was found under SS conditions. This illustrates the usefulness of 18O for selecting the genotypes best suited to differing water conditions.
English
Lucia Segura
CIMMYT Staff Publications Collection