On the $\omega$-independence of quasivarieties of nilpotence groups

We prove that there exists a set $\mathcal{R}$ of quasivarieties of nilpotent groups of class two any quasivariety from $\mathcal{R}$ does not have an independent basis of quasi-identities to the class $\mathcal{N}_{2}$ of $2$-nilpotent groups and has an $\omega$-independent basis of quasi-identities to $\mathcal{N}_{2}$. The intersection of all quasivarieties in $\mathcal{R}$ has an independent basis of quasi-identities to $\mathcal{N}_{2}$. The set of such sets $\mathcal{R}$ is continual.