Ugaritic

ksm, ks̀m - spelt, emmer wheat (DUL 462)

probably equated with Akk. kunāšu ‘spelt’ in the polyglot vocabulary: [ku-na]-šu = ˹ku˺-sú-mu (Huehnergard 1987a:139)

PC
*kussam-t- - spelt (grain similar to wheat) (Kogan 2015: 296)
one wonders whether it might represent a secondary rebuilding of *kunāṯ- under the influence of *ksm rather than a completely new independent formation (Kogan 2015: 297)