In my application i have a custom field called Column__c, what i want is when i create a new Column__c record, the Column__c Name will be added automatically in the status picklist field in Task Standard object. By default status field has (Not Started, In Progress, Completed, Waiting on, someone else, Deferred). is it possible to add new picklist value for status field via trigger/programmatically? anyone is willing to help will be appreciated , thanks.
Not without using the Metadata API, such as FinancialForce's Metadata API. However, it really shouldn't matter, since you can store whatever value you want in a pick list, so long as "enforce pick list values" is not enabled. Simply have your trigger assign whatever value you choose, and that record will retain that record, even if it's not on the list of accepted values.