Riesling vs Vitis vinifera

Riesling and Vitis vinifera both are nouns.

Word	Noun	Adjective	Verb	Adverb
Riesling	Yes	No	No	No
Vitis vinifera	Yes	No	No	No

As nouns, Vitis vinifera is a hypernym of Riesling; that is, Vitis vinifera is a word with a broader meaning than Riesling:

Riesling: white grape grown in Europe and California
Vitis vinifera: common European grape cultivated in many varieties; chief source of Old World wine and table grapes

Other hypernyms of Riesling include common grape vine, vinifera, vinifera grape.

Riesling (noun)	Vitis vinifera (noun)
fragrant dry or sweet white wine from the Rhine valley or a similar wine from California	common European grape cultivated in many varieties; chief source of Old World wine and table grapes
white grape grown in Europe and California