Evaluation of Cateto Maize Accessions for Grain Yield and Other Agronomic Traits in Temperate and Tropical Environments

The temperate maize (Zea mays L.) race Cateto may have potential for improving grain quality in temperate breeding programs. Temperate germplasm may also be useful in tropical breeding programs for improving yield, agronomic traits, and grain quality. The objective of our study was to assess the yield potential of Cateto race accessions testcrossed with two Corn Belt inbreds for grain yield and other agronomic traits in both temperate and tropical environments. Exotic inbreds representing Cateto, intermediate, and non-Cateto races were crossed to two U.S. Corn Belt inbreds (Mo17 and B73). Testcrosses (F₁s), their F₂ and backcross generations, and four checks were evaluated in 1989 through 1991 at three temperate (two in Iowa and one in Missouri) and two tropical (Florida and Zimbabwe) locations. Data were recorded for grain yield, harvest moisture content, days to tassel, ear height, stalk lodging, and root lodging. The testcross-by-generation interaction was significant for all traits, except grain yield, whereas the testcross-by-tester interaction was significant for ear height, stalk lodging, and root lodging. B73 contributed more favorable alleles for improved standability and grain yield than did Mo17. Although the testcross by location interaction was significant for all traits, the tropical and temperate environments ranked testcrosses similarly. The tropical locations had both the highest and the lowest mean grain yields. The best testcrosses identified in temperate locations may have potential for introgression in the tropics. Joint Contribution from USDA-ARS and Journal Paper no. J-15062 of the Iowa Agric. and Home Economics Exp. Stn., Ames, IA. Project 3082. Prt of a dissertation submitted by A. Hameed in partial fulfillment of the requirements for a Ph.D. degree.