Strips
Strips are highlighted areas on a chart within a defined range of values (minimum and maximum) of the axis they belong to, and are used to visually represent a range of values behind a series to trace whether the series point values fall in or out of that range.
Strips are child elements of the argument and value axes. You can access the collection of strips using the BootstrapPolarChartAxisSettingsBase.StripCollection property of an axis. Use the strip’s BootstrapChartStrip.StartValue and BootstrapChartStrip.EndValue properties to set the bounds of a strip.
<dx:BootstrapPolarChart ID="BootstrapPolarChart1" runat="server" ...>
<ArgumentAxis ... >
<StripCollection>
<dx:BootstrapChartStrip StartValue="40", EndValue="50" />
<dx:BootstrapChartStrip StartValue="70", EndValue="80" />
</StripCollection>
</ArgumentAxis>
...
</dx:BootstrapPolarChart>