DNS zone data transfer from slave to master

I have configured a test dns server with master and slave for abc.com . For every update in zone file update is working fine from master to slave , But i want slave to have rights to update the zone file so that zone file automatically gets updated.

(Attn : People with "rsync option" kindly abstain from posting soln )

Master (named.conf) :

acl loc { 127.0.0.1; 10.0.0.0/8; };
options {
        listen-on port 53 { 127.0.0.1; 10.1.0.171 ; };
        directory       "/var/named";
        dump-file       "/var/named/data/cache_dump.db";
        statistics-file "/var/named/data/named_stats.txt";
        memstatistics-file "/var/named/data/named_mem_stats.txt";

        // Those options should be used carefully because they disable port
        // randomization
        // query-source    port 53;
        // query-source-v6 port 53;

        allow-query     { loc;  };
        allow-query-cache { loc; };
};


server 10.1.0.172 {
keys { ddns-update ; };
};

include "/etc/ddns-update.dnskey";


logging {
        channel default_debug {
                file "data/named.run";
                severity dynamic;
        };
};
view localhost_resolver {
        match-clients      { loc; };
        match-destinations { loc; };
        recursion yes;
//        include "/etc/named.root.hints";
//        include "/etc/named.rfc1912.zones";

zone "abc.com" IN {
        type master;
        file "abc.com.zone";
        notify yes;
        allow-transfer { loc;};
        allow-update {  key "ddns-update" ; };
};

zone "0.1.10.in-addr-arpa" {
      type master;
      file "0.1.10.zone";
      allow-transfer { loc; };
      allow-update { key "ddns-update" ; };
};





};

Slave (named.conf) :

acl loc { 127.0.0.1; 10.0.0.0/8; };
options {
        listen-on port 53 { 127.0.0.1; 10.1.0.172 ; };
        directory       "/var/named";
        dump-file       "/var/named/data/cache_dump.db";
        statistics-file "/var/named/data/named_stats.txt";
        memstatistics-file "/var/named/data/named_mem_stats.txt";

        allow-query     { loc; };
        allow-notify { loc; };
};

include "/etc/ddns-update.dnskey";

server 10.1.0.171 {
    keys {  ddns-update;
    };
};


logging {
        channel default_debug {
                file "data/named.run";
                severity dynamic;
        };
};
view localhost_resolver {
        match-clients      { loc; };
        match-destinations { loc; };
        recursion yes;
//        include "/etc/named.root.hints";
        include "/etc/named.rfc1912.zones";

zone "abc.com" IN {
        type slave;
        file "abc.com.zone";
        notify yes;
        masters { 10.1.0.171; };
        allow-transfer { loc; };
        allow-update { key "ddns-update"; };
};


zone "0.1.10.in-addr-arpa" {
type slave ;
masters { 10.1.0.171; };
file "10.1.0.zone";
};


};