Is Yamoshi a pun on something? All saiyan names are pun on vegetables. Kakaroto (carrot), Vegita (vegetable), Tarble (vegetable), Bardock (Burdock), Totepo (potato), Broly (broccoli), Cabba (cabbage), etc.

Now Akira Toriyama gave recently in an interview the name of the first super saiyan and the first super saiyan god, Yamoshi. Is this a pun on something?
Yamoshi is indeed a pun for Moyashi (もやし).

Moyashi is the Japanese term for Bean Sprouts. Bean sprouts are a common ingredient in many Japanese dishes such as stir fries and soups.