What do the stars indicate under the seeds when you go to the market? There is a bar and when crops are harvested a yellow line appears, the more you plant and harvest the longer the line and then a star is filled in with yellow paint.
The stars located under each seed in the FarmVille Market is your ranking so far in the 3 Mastery Levels. There are 3 levels for each seed - each requiring a different total number of plants harvested. Once you complete all 3 levels, you will be awarded with a Mastery Sign Post for your farm, we well as receive an XP bonus and coin bonus.