M6 is an improved variety of S. chacoense, introduced in 2014. It is homozygous for the Sli gene. It is able to self-pollinate and produce vigorous progeny, and is a day neutral tuberizer. M6 can be used in breeding with domesticated diploids to reliably introduce self-compatibility, since the Sli gene is dominant.
These tubers are seed grown progeny of M6. There are several slightly different phenotypes, but they should all still be homozygous for Sli.