diff --git a/lib/redmine/helpers/gantt.rb b/lib/redmine/helpers/gantt.rb
index 5bf0a1e98..3238de8cf 100644
--- a/lib/redmine/helpers/gantt.rb
+++ b/lib/redmine/helpers/gantt.rb
@@ -749,11 +749,7 @@ module Redmine
                          :class => "#{options[:css]} task_todo",
                          :id => html_id}
           if options[:issue]
-            rels_hash = {}
-            issue_relations(options[:issue]).each do |k, v|
-              rels_hash[k] = v.join(',')
-            end
-            content_opt[:data] = {"rels" => rels_hash}
+            content_opt[:data] = {"rels" => issue_relations(options[:issue]).to_json}
           end
           output << view.content_tag(:div, '&nbsp;'.html_safe, content_opt)
           if coords[:bar_late_end]
diff --git a/public/javascripts/gantt.js b/public/javascripts/gantt.js
index e16f4028f..51e2257e0 100644
--- a/public/javascripts/gantt.js
+++ b/public/javascripts/gantt.js
@@ -19,14 +19,11 @@ function getRelationsArray() {
       var issue_id = element_id.replace("task-todo-issue-", "");
       var data_rels = $(element).data("rels");
       if (data_rels != null) {
-        for (rel_type_key in issue_relation_type) {
-          if (rel_type_key in data_rels) {
-            var issue_arr = data_rels[rel_type_key].toString().split(",");
-              $.each(issue_arr, function(index_issue, element_issue) {
-                arr.push({issue_from: issue_id, issue_to: element_issue,
-                          rel_type: rel_type_key});
-              });
-          }
+        for (rel_type_key in data_rels) {
+          $.each(data_rels[rel_type_key], function(index_issue, element_issue) {
+            arr.push({issue_from: issue_id, issue_to: element_issue,
+                      rel_type: rel_type_key});
+          });
         }
       }
     }