Which breed was created to provide registration opportunities for horses with significant white markings?

The American Paint Horse breed was specifically created to provide registration opportunities for horses that have distinctive white markings combined with any color pattern, particularly spotting. This breed emphasizes the combination of color and conformation, allowing for the inclusion of horses that might not fit into other breed registries due to their color patterns. The recognition of such horses displays the breed's commitment to diverse appearances while maintaining breed standards.

While other breeds like the Appaloosa also feature unique coat patterns, the intent behind their creation was different, focusing more on specific characteristics such as spots or patterns rather than the registration of horses based solely on white markings. The American Standardbred and Thoroughbred breeds do not emphasize color in their registration criteria; they prioritize pedigree, racing performance, and conformation, which makes them unsuitable for the question regarding white markings and their significance in breed identity.