muscles used in vertical jumping according to the Parissi school - these guys have trained a lot of guys who can jump over 36inches
glutes and erectors - 40%
hamstrings - 25%
shoulders 15%
20% - calves +quads+abs+arms+back+other
http://www.dynamic-eleiko.com/sportivny/library/index.html
A high correlation was found between the strength of the hamstrings and the vertical jump results of weightlifters. Furthermore, the vertical jump results of weightlifters have a high, but inversely proportional connection to the speed with which the knees shift under the barbell. The stronger the hamstrings, the higher the vertical jump of weightlifters, the faster the knees shift under the barbell in the explosion
off course this doesn't mean you should be doing leg curls
HIP EXTENSION!
exercises - squats (all types), snatch grip deadlift, depth jumps (wait till your strong enough), power snatch/clean, power jerk, oly style pulls, overhead press, hypers, reverse hypers, romanian deadlifts, ab work, jump squats, med ball snatch throws, 30m accleration sprints, push press
and off course lots of jumping!