yes,you are right and i changed my code as:

public class sublist
{
public boolean chklist{get;set;}
public string submenu{get;set;}
}
public class statuslist{
public string statusName{get;set;}
public list<sublist> statussubmenu = new list<sublist>();
public list<sublist> getstatussubmenu()
{
return statussubmenu;
}

public list<statuslist> parentlist = new list<statuslist>();

public list<statuslist> getparentlist()
{

return parentlist;
}


public void updatestatusop()
{
statusop = true;
List<Status_Option__c> statop = new List<Status_Option__c>([select Name,Current_Build_Status__c,Next_Build_Status__c
from Status_Option__c
where Product_Group__c = :productId ]);
system.debug('list size is:'+statop.size());


for(integer i=0;i<statop.size();i++)
{
statuslist tmp =new statuslist();


system.debug('status name is'+statop.get(i).Name);

tmp.statusName = statop.get(i).Name;
system.debug('values in statusoption are:'+tmp.statusName);
for(integer j=0;j<statop.size();j++)
{
sublist tmp1 = new sublist();
if(i==j)
{
system.debug('$$$$$$$$$$$ we are in if statment$$$$$$$$$$$$$$$');
continue;
}
else
{

tmp1.chklist = false;
tmp1.submenu = statop.get(j).Name;
tmp.statussubmenu.add(tmp1);
system.debug('*****we are in else*************************');

//tmp1.statussubmenu.add(statop.get(j).Name);
system.debug('status name in inner loop is is'+tmp);
}


}
parentlist.add(tmp);

}
}

my visualforce page is:

<apex:pageblock title="STATUS OPTIONS" rendered="{!statusop}">
<apex:outputpanel >
<table>
<apex:repeat value="{!parentlist}" var="p1">

<tr>
<td>
<h1><b> {!p1.statusName} </b></h1>
<apex:param name="statusopname" assignTo="{!newstatusname}" value="{!p1.statusName}"/>
</td>
</tr>
<tr><td>
<h5> <b> Next Status Option</b> </h5>
</td></tr>


<tr> <apex:repeat value="{!p1.statussubmenu}" var="p12" >

<td colspan='2'><apex:inputcheckbox value="{!p12.chklist}">{!p12.submenu}

</td>

</apex:repeat></tr>

</apex:repeat>

the o/p is

value1

chbox vale2  chkboc value3

chkbox  value4 chkbox value5

value2

chbox value1 chkbox value3

chbox value4 chbox value5

...

now ,if i click chkboxes the correspondong value should bo store in custom object

if i click value2 and value3 under value1 then assign value1 to status_c. name=value1

status.nextstatusname=vallu2 value3

how can we do this 

any suggestion?