Funding of Defined Benefit Plans

May a business fund a defined benefit plan with any source of income?  Specifically schedule E income?

Is there an employee here? I think Schedule E is passive income. I am worried about compensation.  See publication 560 for the fun part:  https://www.irs.gov/pub/irs-pdf/p560.pdf

You have different issues at play here. You need to be considered an employee or self-employed and have "compensation" or net earned income upon which to base a contribution. Assuming you have that, the source from which the business funds the contribution does not matter although should consult with accountant regarding deductibility from certain sources. 

The business can fund the plan from whatever revenue they have. The Minimum Required Contribution to the Plan must be made in cash.

The benefits that accrue to participants in the Plan have to be based on W-2 wages or Self Employment earned income.

If the business's only income is on Schedule E it's likely there are no benefits to accrue to employees.

Gina, Cuse, and Lou, I figured this would be the case, just as it is in a DC plan.  Appreciate your time and input!!