TUNICA, MS— Myriad Entertainment & Resorts has agreed to purchase 500 acres of land here to create a destination resort called the Myraid Botanical Resort. The proposed development would feature lodging, gaming, convention space, retail outlets, golf, and leisure real estate. The land had been owned by the locally-based Perry family. No purchase price was disclosed. The site is a 30-minute drive from Memphis, where Myriad is based.