Partitive and wholative are terms applied to certain genitival constructions, but they refer to the same linguistic phenomenon. Grammarians taxonomize such data in order to systematize and clarify it.
While genitival phrases like πρωτότοκος πάσης κτίσεως might be considered partitive by some, indicating that the head noun lingually signifies part of a greater whole, other grammarians opt to use the descriptive label "wholative" for such phrases since πάσης κτίσεως does not refer to a portion of anything but it is the head noun of the construction that denotes a part of X in Colossians 1:15 and where one finds similar grammatical constructs. It thus seems more appropriate to label the genitive in 1:15 (if one construes the syntax in this manner) as a wholative instead of a partitive genitive (or genitive of the whole).
Emphasizing the notion of the whole rather than the part for this kind of genitive is not completely novel since William Gardner Hale and Carl Darling Buck (A Latin Grammar) write:
"The name Partitive Genitive, which is often used, is convenient because of its shortness. But the student should remember that what is expressed by the Genitive word itself is the WHOLE, not the part" (page 183).
Buck and Hale therefore prefer to call this structure Genitive of the Whole or Wholative. Wallace shows that the partitive genitive "is a phenomenological use of the genitive that requires the head noun to have a lexical nuance indicating PORTION" (GGBB, 84, emphasis in original). He points out that some have proferred the nomenclature "wholative genitive" for these grammatical constructs in Greek or they have been called genitive of the divided whole, terminology which Wallace himself does not seem to prefer.