Two series of models and their yields are presented in this paper .
The first series consists of 20 M _ { \odot } models with varying initial metallicity ( solar down to Z = 10 ^ { -8 } ) and rotation ( \upsilon _ { ini } = 0 - 600 km s ^ { -1 } ) .
The second one consists of models with an initial metallicity of Z = 10 ^ { -8 } , masses between 20 and 85 M _ { \odot } and average rotation velocities at these metallicities ( \upsilon _ { ini } = 600 - 800 km s ^ { -1 } ) .
The most interesting models are the models with Z = 10 ^ { -8 } ( [ Fe/H ] \sim - 6.6 ) .
In the course of helium burning , carbon and oxygen are mixed into the hydrogen burning shell .
This boosts the importance of the shell and causes a reduction of the size of the CO core .
Later in the evolution , the hydrogen shell deepens and produces large amount of primary nitrogen .
For the most massive models ( M \gtrsim 60 M _ { \odot } ) , significant mass loss occurs during the red supergiant stage .
This mass loss is due to the surface enrichment in CNO elements via rotational and convective mixing .

The yields of the fast rotating 20 M _ { \odot } models can best reproduce ( within our study ) the observed abundances at the surface of extremely metal poor ( EMP ) stars .
The wind of the massive models can reproduce the CNO abundances of the carbon–rich UMPs , in particular for the most metal poor star known to date , HE1327-2326 .