It looks like you want this pluging as it follows your existing code, maybe the plug in js file got left out somewhere.
http://www.texotela.co.uk/code/jquery/select/
var myOptions = {
"Value 1" : "Text 1",
"Value 2" : "Text 2",
"Value 3" : "Text 3"
}
$("#myselect2").addOption(myOptions, false);
// use true if you want to select the added options ยป Run