A noun appearing as G. gaust “corn, crop (espec. of cereal)” in the Gnomish Lexicon of the 1910s based on the early root ᴱ√ı̯aƀa [YAɃA] (GL/38), since in Gnomish of the 1910s an initial y usually became g (HPG/§2.1).
Neo-Sindarin: Since the root ᴹ√YAB “fruit” survived in Tolkien’s later writing, I would salvage this Gnomish noun as ᴺS. iaust to better fit later phonology. Furthermore, I would use it only in the sense “crop, ✱yield, produce”, where for “corn [= cereal grain]” I would use N. iau “corn” from The Etymologies (Ety/YAB).
An adjective appearing as G. calon “grown (of plants), budd[ing], in blade (of corn)” in the Gnomish Lexicon of the 1910s, based on the early root ᴱ√cala having to do with growth (GL/25). Initially Tolkien said this word was the equivalent of G. côl “vegetable”, but this was deleted.
Neo-Sindarin: For purposes of Neo-Sindarin, I would update this word to ᴺS. galen “grown (esp. of plants)” based on the later root √GAL “grow”.