Final answer:
The advantage of breeding a new dog variety for Mississippi Delta farmers is the possibility of the breed developing additional beneficial traits beyond the primary objective of controlling rodents.
Step-by-step explanation:
An ADVANTAGE of potentially developing a new breed of dogs to meet the farmers' needs in the Mississippi Delta is that the new breed could possibly attain other traits that could aid in aspects beyond the farmers’ original needs. By carefully selecting for traits such as small size for navigating the granaries and a high tolerance for heat, the resultant breed may inadvertently acquire additional beneficial traits. These might include enhanced agility, strong hunting instincts inherited from their wolf ancestors, or a temperament conducive to training, making them not only effective rodent controllers but potentially versatile farm dogs capable of undertaking various tasks.