<select id="variant_to_stock" name="variant_to_stock">

<option value="-1" {if $selected_product[selected_product].stock_variant_group_id==-1} selected="selected"{/if}>Variant based stock level is not set</option>

{section name=list_all_variant_group loop=$list_all_variant_group}
	<option value="{$list_all_variant_group[list_all_variant_group].variant_group_id}" {if $list_all_variant_group[list_all_variant_group].variant_group_id==$selected_product[selected_product].stock_variant_group_id}selected="selected"{/if}>{$list_all_variant_group[list_all_variant_group].group_name}</option>
{/section}
</select>