I have cloned the repo of MoonBeam and run the chain as a "Development chain" but the chain is not producing blocks. Are there any reference links which i can follow to remove dependency from relay chain?
Moonbeam is an implementation of Frontier, an Ethereum compatibility layer for Substrate. Frontier is a codebase managed by the team behind Moonbeam and Wei Tang. You need not fork Moonbeam's repository. Simply take advantage of Frontier.
Check it out here:
Similar to the Basic Substrate Node template, there is a basic Frontier Substrate Node Template to start from which you will be able to produce blocks immediately:
That being said, why will you not want to be a parachain? The economic security is significantly lesser starting out as a solochain (Orders of magnitude lesser). But if you are keen to try it out as a testnet, by all means be a solochain for now :)