Remove Gridlines in Chart - BI Publisher

To remove the regular gridlines :

<O1MajorTick visible="false"/>
<X1MajorTick visible="false"/>
<Y1MajorTick visible="false"/>
<Y2MajorTick visible="false"/>

These will turn off all grid lines 

For  'quadrant' lines we need :
<QuadrantLine lineColor="#64ff" visible="false"/> - I just left the lineColor attribute in there for those of you wanting to chage the color rather than remove them.

Source: https://blogs.oracle.com/xmlpublisher/entry/bubblin_charts