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 i mproving grain quality in temperate breeding programs. Temperate germp lasm may also be useful in tropical breeding programs for improving yi eld, agronomic traits, and grain quality. The objective of our study w as 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 represent ing Cateto, intermediate, and non-Cateto races were crossed to two U.S . Corn Belt inbreds (Mo17 and B73). Testcrosses (F(1)s), their F-2 and backcross generations, and four checks were evaluated in 1989 through 1991 at three temperate (two in Iowa and one in Missouri) and two tro pical (Florida and Zimbabwe) locations. Data were recorded for grain y ield, harvest moisture content, days to tassel, ear height, stalk lodg ing, and root lodging. The testcross-by-generation interaction was sig nificant 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 stan dability and grain yield than did Mo17. Although the testcross by loca tion interaction was significant for all traits, the tropical and temp erate environments ranked testcrosses similarly. The tropical location s had both the highest and the lowest mean grain yields. The best test crosses identified in temperate locations may have potential for intro gression in the tropics.