I have a VF page in which I have created a picklist using SelectList and SelectOption. I am now facing final hurdle: Selected value getting changed to default one once I click on Save. I am not sure how should I save the value of SelectList without it being revert back to default one.

This is some part of my VF page:

<apex:pageBlockSection title="Technical Approval" id="techapprovalsection" >
         <apex:pageBlock> 
           <apex:pageBlockSectionItem >
               <apex:outputLabel value="Technical Approver 1"></apex:outputLabel>
               <apex:selectList multiselect="false" required="true" value="{!TechnicalApprover1}" size="1">
                <apex:selectOptions value="{!TechnicalAppList}"/>
               </apex:selectList>
             </apex:pageBlockSectionItem>
           </apex:pageBlock>

         <apex:pageBlock >
           <apex:pageBlockButtons location="bottom">
             <apex:commandButton value="Save" action="{!dosave}"/>
           </apex:pageBlockButtons>
         </apex:pageBlock>

Below is some portion of my Controller class:

public class SubmitforApprovalController {
public SubmitforApprovalController() {
searchTechApproval(OfferType, SalesPrice, MOMargin, objMO);
}

public List<SelectOption> searchTechApproval(String OfferType, Decimal SalesPrice, Decimal MOMargin, Custom1__c objMO)
{
 QueriedTechApprovers= [Select Id, Name,                    Approval_Level__c, GID__c, Mail__c, 
                                         Offer_Type__c, SalesPrice_Range__c, Signature__c, 
                                        TotalMargin_Range__c, Max_Stages__c, Stage__c, 
                                        First_Name__c, Last_Name__c from Approver__c 
                                        Where Sales_Volume_LB__c <= :TotalPrice AND 
                                        Sales_Volume_UB__c > :TotalPrice];
if(QueriedTechApprovers.size()>0){
            TechnicalApprover1 = QueriedTechApprovers[0].Name;

if(QueriedSalesApprovers.size()>0){
        for(Approver__c app : QueriedSalesApprovers){
          lstSalesApprovers.add(new SelectOption (app.Name,app.Name));
 }
}

public pageReference dosave(){
if(!String.isEmpty(TechnicalApprover1) && QueriedTechApprovers.size()>0){
       Approver__c TechApproverChange1 = [Select Id, Name, Stage__c,First_Name__c, Last_Name__c from Approver__c WHERE ID =: TechIDs AND Name =: TechnicalApprover1 LIMIT 1];
        Approval__c apptech1 = new Approval__c();
        apptech1.Main_Offer_Name__c = objMO.Id;
        apptech1.Approver_Name__c = TechApproverChange1.Id;
        apptech1.Stage__c = TechApproverChange1.Stage__c;
        insert apptech1;
        isTechApprover = true;
     }

Whenever I click on Save button, page refreshes and value of picklist changes to default one set by controller. I want it to remain as it is.