Complex sentence: The study of cultigen nomenclature and classification forms a major part of cultivated plant taxonomy and the rules and recommendations for their naming are detailed in the "International Code of Nomenclature for Cultivated Plants" (Cultivated Plant Code).
Split into simpler sentences: The study of cultigen nomenclature and classification forms a major part of cultivated plant taxonomy. Cultigens can be named in several ways; a prominent naming system is the one that is laid down in the "International Code of Nomenclature for Cultivated Plants" (Cultivated Plant Code).