Can I pass a variable in a template binding?

Use

<!-- ko template: { name: tmplOne, templateOptions: {myvar: 'apple'} } -->

More here: http://www.knockmeout.net/2011/03/quick-tip-reusing-template-by-passing.html

You can supply a data parameter to the template binding and define an object literal if you want just like you are doing:

<!-- ko template: { name: tmplOne }, myvar: 'apple' -->

instead do this:

<!-- ko template: { name: tmplOne, data: { myvar: 'apple' } } -->

http://knockoutjs.com/documentation/template-binding.html

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