The most common and most likely answer to this crossword clue is the 7 letter word MAKINGS
I've seen this crossword clue in The Times
M
A
K
I
N
G
S
Buddy explains!

The straight part
We know that "Necessary qualities" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case necessary qualities = makings.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does MAKINGS mean?
MAKINGS noun- The act of forming, causing, or constituting; workmanship; construction.
- Process of growth or development.
- That which is needed for something: necessary ingredients.