This is the Iroquois Legend of the Three Sisters.  The term “Three Sisters” emerged from the Iroquois creation myth. It was said that the earth began when “Sky Woman” who lived in the upper world peered through a hole in the sky and fell through to an endless sea. The animals saw her coming, so they took the soil from the bottom of the sea and spread it onto the back of a giant turtle to provide a safe place for her to land. This “Turtle Island” is now what we call North America.

Sky woman had become pregnant before she fell. When she landed, she gave birth to a daughter. When
the daughter grew into a young woman, she also became pregnant (by the West wind). She died while
giving birth to twin boys. Sky Woman buried her daughter in the “new earth.” From her grave grew
three sacred plants—corn, beans, and squash. These plants provided food for her sons, and later, for all
of humanity. These special gifts ensured the survival of the Iroquois people.