CROP BREEDING, GENETICS & CYTOLOGY Identification of Tropical and Temperate Maize Populations Having Favorable Alleles for Yield and Other Phenotypic Traits

ABSTRACT evaluated when they have been adapted for flowering date, some of these GEM populations were crossed toIf tropical germplasm is to be useful in increasing maize (Zea temperate maize inbreds B73 and Mo17. Together withmays L.) grain yield, populations containing favorable alleles not present in elite hybrids need to be identified. Thus, a major objective the work to collect, acquire, and use exotic materials, of this study was to identify tropical and temperate populations con- developing optimal methods for identifying populations taining favorable alleles useful for improving the Corn Belt hybrid that have favorable alleles not present in elite germ-FR1064 3 LH185 (a commercial hybrid representative of the typical plasm and for introgressing these alleles into elite breed-Stiff-Stalk 3 Lancaster heterotic pattern). A group of tropical popula- ing material is important. tions and hybrids from the Germplasm Enhancement of Maize Project Theory for identifying populations containing favor-(GEM) crossed to either Mo17 or B73 (temperate maize inbreds) able alleles for improving an elite single cross is availablewas studied. In addition, a group of temperate accessions was evalu-(Dudley, 1987, 1988a). This theory assumes that for anyated. Grain yield, flowering date, plant height, ear height, and pene-two lines there are four classes of loci. Class i havingtrometer reading were evaluated using Dudley’s method for identi-favorable alleles (11) present in both parents (I1 andfying populations with favorable alleles. Only three accessions of 41 had positive and significant relative numbers of favorable alleles for I2) of the elite hybrid. Class j being 11 for I1 and havin