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

Because many exotic corn (Zea mays L.) races have different evolutiona ry histories from those of U.S. races, they may possess unique, favora ble 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 hybr ids. Eighteen exotic inbreds were crossed to two Corn Belt inbreds, Mo 17 and B73, which represent the 'Lancaster Sure Crop' and the 'Iowa St iff Stalk Synthetic' backgrounds, respectively. A randomized complete block design was used to evaluate testcrosses (F(1)s), their F-2 and b ackcross (to the Corn Belt inbreds) generations, and four checks grown at two locations in Iowa and at one location in Missouri. The experim ent showed significant differences among races for 1000-kernel weight, test weight, grain yield, and harvest moisture content. Testcrosses a nd generations were significantly different for kernel weight, test we ight, breakage susceptibility, grain yield, and harvest moisture conte nt. Significant differences were also found between testers for all tr aits except moisture. Entry x tester interaction, however, was signifi cant only for breakage susceptibility and yield, whereas entry x gener ation interaction was significant for all the traits except breakage s usceptibility. This study showed that Cateto-type inbreds have the pot ential to improve test weight of Corn Belt hybrids. The Cateto race in breds also contributed favorable alleles for lowering harvest moisture content, which may indirectly help reduce breakage losses.