Heterosis and Combining Ability among Subtropical and Temperate Intermediate-Maturity Maize Germplasm

Information about combining ability and heterotic patterns among CIMMYT's maize (Zea mays L.) gene pools and populations should assist research programs in their hybrid development activities. A nine-parent diallel was formed to (i) study the combining ability of CIMMYT's subtropical and temperate intermediate-maturity maize gene pools and populations and (ii) evaluate the potential of CIMMYT's subtropical and temperate materials as exotic germplasm sources for temperate breeding programs. Parents and crosses were evaluated in 5 environments in Mexico and 11 in the USA