EVALUATION OF CATETO MAIZE ACCESSIONS FOR GRAIN-YIELD AND PHYSICAL GRAIN QUALITY TRAITS

Because many exotic corn (Zea mays L.) races have different evolutionary histories from those of U.S. races, they may possess unique, favorable alleles for physical grain quality traits. This study explored the effectiveness of using exotic inbreds from Uruguay, Argentina, South Africa, and Taiwan (representing 'Cateto'-type, intermediate, and non-Cateto races) to improve physical grain quality of U.S. Corn Belt hybrids. Eighteen exotic inbreds were crossed to two Corn Belt inbreds, Mo17 and B73, which represent the 'Lancaster Sure Crop' and the 'Iowa Stiff Stalk Synthetic' backgrounds, respectively. A randomized complete block design was used to evaluate testcrosses (F(1)s), their F-2 and backcross (to the Corn Belt inbreds) generations, and four checks grown at two locations in Iowa and at one location in Missouri. The experiment showed significant differences among races for 1000-kernel weight, test weight, grain yield, and harvest moisture content. Testcrosses and generations were significantly different for kernel weight, test weight, breakage susceptibility, grain yield, and harvest moisture content. Significant differences were also found between testers for all traits except moisture. Entry x tester interaction, however, was significant only for breakage susceptibility and yield, whereas entry x generation interaction was significant for all the traits except breakage susceptibility. This study showed that Cateto-type inbreds have the potential to improve test weight of Corn Belt hybrids. The Cateto race inbreds also contributed favorable alleles for lowering harvest moisture content, which may indirectly help reduce breakage losses.