Fields and Screens - JIRA 6.x Administration Topic - page 92

How to do it…
JIRA uses Velocity templates to render custom fields. These templates are mostly HTML
with some special symbols. You can find all these files in the JIRA_INSTALL/
atlassian-jira/WEB-INF/classes/plugins/fields directory, and the edit
view templates are in the edit subdirectory.
So we need to open the edit-select.vm file in a text editor and remove the following
code snippet:
#if (!$fieldLayoutItem || $fieldLayoutItem.required == false)
<option
value="-1">$i18n.getText("common.words.none")</option>
#else
#if ( !$configs.default )
<option
value="">$i18n.getText("common.words.none")</option>
#end
#end
Make sure you do not change any other lines, then save the file, and restart JIRA.
Tip
You can remove the None option from other custom field types, such as multi-select by
editing the appropriate file, for example, edit-multiselect.vm .