i i am new to salesforce. I want to display some records on a pageblocktable, which must be based on the picklist field. e.g. If i select Quarter4 from quarter picklist field pageblocktable must show records for the particular quarter. Anyone know how to do that? I am attaching my VF page and controller code here. VF page-
<apex:page standardController="contact"  extensions="cntrl_bulk_test"> <!-- controller="cntrl_bulk_test" -->
    <apex:form id="frm">
        <apex:pageBlock id="pgBlkSkilllevel">
            <apex:pageBlockTable value="{!lsttopiclevel1 }" var="a">
                
                <apex:column headerValue="Skill Group">
                    <apex:outputField value="{!a.Skill_Group__c}"/>
                  <!--  <apex:inputfield value="{!a.Skill_Group__c}"/> -->
                </apex:column>
                  
                <apex:column headerValue="Topic Name">
                    <apex:outputField value="{!a.Topic__r.Name}"/>
                </apex:column>
                  
                <apex:column headerValue="Skill Target">
                    <apex:outputField value="{!a.skill_level_expected__c}"/>
                </apex:column>
                  
                <apex:column headerValue="Skill Level">
                    <apex:inputfield value="{!a.Skill_Level__c}"/>
                </apex:column>
                  
                <apex:column headerValue="Year">
                    <apex:inputfield value="{!a.Year__c}"/>
                </apex:column>  
                
                <apex:column headerValue="Quarter">
                    <apex:inputfield value="{!a.Quarter__c}"/>
                </apex:column>    
                
            </apex:pageBlockTable>
        <br/>
       
        <apex:commandButton value="Save" action="{!saveSkillLevelRating}" /> <!--onclick="window.top.location='/{!Contact.id}'; return false"-->
        </apex:pageBlock>
    </apex:form>
</apex:page>

controller-
public with sharing class cntrl_bulk_test
{
    Public static Id EmployeeId {get;set;}
    Public  List<Contact_Topic_Scale__c> lsttopiclevel{get;set;}
    list<Contact_Topic_Scale__c> LstSkilllevels = new list<Contact_Topic_Scale__c>();
    public List<Contact_Topic_Scale__c> lsttopiclevel1 {get;set;}
   public ApexPages.StandardController controller {get; set;}    

    public cntrl_bulk_test(ApexPages.StandardController controller)
    {
         this.controller = controller;
         EmployeeId =system.currentpagereference().getparameters().get('id');
         Contact coninfo = [select name from contact where id =: controller.getId()];
         lsttopiclevel1 = new List<Contact_Topic_Scale__c>([SELECT Id, Core_Skill_Set__c,Contact_Skill_Set__c,Delta_Actual_vs_Expected__c,Employee__c,Quarter__c,Skill_Group__c,Skill_Level__c,skill_level_expected__c,Year__c,Topic__r.Name FROM Contact_Topic_Scale__c where Employee__c =: coninfo.name ORDER BY Skill_Group__c ASC ]);
    }
 
    Public PageReference saveSkillLevelRating()
    {
           //controller.save(); // call save method from standart controller
           //System.debug('*******saveSkillLevelRating0*******');
          
           //PageReference pageRef = system.currentpagereference();
           PageReference pageRef = ApexPages.currentPage();
           System.debug('********************************************************************************lsttopiclevel=' + lsttopiclevel1 );
           update lsttopiclevel1 ;
           System.debug('********************************************************************************lsttopiclevel=' + lsttopiclevel1 );
           return null;
           //return pageRef ;
           
    }   
}