Lineage What Is The Theme Of The Poem Lineage By Margaret Walker?

What is the theme of the poem Lineage by Margaret Walker? - lineage

or maybe what the poem is it? I read, but I do not understand.

Lineage
My grandmothers were strong.
They followed plows and bent to go to work.
They marched through the fields for planting.
They touched earth and grain grew.
They were full of strength and song.
My grandmothers were strong.

My grandmothers are full of memories
Smell of soap and onions and wet clay
With veins rolling around on fast hands
They have many clean words to say.
My grandmothers were strong.
Why I'm not like them?