[SalesForce] Rerendering on Delete button is not working

I have delete button on page which deletes selected record from page.
The moment I click on button, Record gets deleted but page is not getting refreshed automatically.
To see the changes I need to refresh the page mauanlly.

Below is my Visualforce Page,

<apex:page Controller="testPageExt" >
    <apex:stylesheet value="/sCSS/25.0/sprites/1342034628000/Theme3/default/gc/versioning.css" />
    <apex:stylesheet value="/sCSS/25.0/sprites/1342034628000/Theme3/default/gc/extended.css" />
        <script>
            window.onload = function(){
            document.getElementsByClassName('headerSearchContainer')[0].style.display = 'none';
            };
        </script>
        <script type="text/javascript">
            function selectAllCheckboxes(obj,receivedInputID){
                var inputCheckBox = document.getElementsByTagName("input");                  
                    for(var i=0; i<inputCheckBox.length; i++){          
                        if(inputCheckBox[i].id.indexOf(receivedInputID)!=-1){                                     
                            inputCheckBox[i].checked = obj.checked;
                        }
                    }
                }
        </script>
    <apex:form >
        <apex:pageBlock title="Supplier List" helpTitle="supplier" helpUrl="/apex/testPage" >
        <apex:pageBlockButtons >
            <apex:commandButton action="{!deleteSelectedSupplier}" value="Delete Supplier" reRender="supplier"/>
        </apex:pageBlockButtons>
            <apex:pageBlockSection showHeader="true" title="List of All Supplier" columns="2" id="PBSection">
                <apex:pageBlockTable value="{!supWrapList}" var="s" id="supplier">
                    <apex:column >
                        <apex:facet name="header"><apex:inputCheckbox onclick="selectAllCheckboxes(this,'inputID')"/></apex:facet>
                        <apex:inputCheckbox value="{!s.isSelected}" id="inputID"/>         
                    </apex:column>
                    <apex:column >
                        <apex:facet name="header">Supplier Name</apex:facet>
                        <apex:commandLink action="{!quoteaction}" value="{!s.supObj.name}" reRender="quote">
                            <apex:param name="sParam" value="{!s.supObj.id}" assignTo="{!supplierValue}"/>
                        </apex:commandLink>
                    </apex:column>     
                </apex:pageBlockTable>
                <apex:pageBlockTable var="r" value="{!quoteList}" id="quote">
                    <apex:column headerValue="Quote Name" value="{!r.name}" />
                </apex:pageBlockTable>
            </apex:pageBlockSection>
        </apex:pageBlock>
    </apex:form>
</apex:page>

*******Controller***********

public with sharing class testPageExt {

public List<Quote__c> quoteList {get;set;}
public List<Supplier__c> supllierList {get;set;}
public String supplierValue {get;set;}
public List<wrapSupplier> supWrapList {get;set;}
public List<Supplier__c> selectedSupplier {get;set;}

public testPageExt() {
    supWrapList = new List<wrapSupplier>();
    supllierList =[Select id, Name from supplier__c];
    system.debug('*********'+supllierList );
    quoteList = null;
    for(supplier__c sObj:supllierList){
        supWrapList.add(new wrapSupplier(sObj));
    }
}

    public pagereference deleteSelectedSupplier(){
        selectedSupplier = new List<Supplier__c>();
        for(wrapSupplier wObj: supWrapList){
            if(wObj.isSelected == True){
                selectedSupplier.add(wObj.supObj);
            }
        }
        Delete selectedSupplier;
        //getSupllieraction();
        return new PageReference ('/apex/testPage');
    }

    public List<Supplier__c> getSupllieraction() {
        supllierList =[Select id, Name from supplier__c];
        return supllierList ;
    }

    public void quoteaction() {
        quoteList = [Select id, name ,RFQ_Supplier__c from Quote__c where RFQ_Supplier__c =:supplierValue ];
    }

    public class wrapSupplier {

        public Supplier__c supObj {get;set;}
        public Boolean isSelected {get;set;}

        public wrapSupplier(supplier__c sObj){

            this.supObj = sObj;
            this.isSelected = False;
        }
    } 
}