diff -ur -x log redmine-3.3-stable_with_long_text-20170217/app/models/issue_query.rb dev/app/models/issue_query.rb
--- redmine-3.3-stable_with_long_text-20170217/app/models/issue_query.rb	2017-02-17 11:23:14.000000000 +0100
+++ dev/app/models/issue_query.rb	2017-03-16 15:16:01.845021275 +0100
@@ -43,6 +43,7 @@
     QueryColumn.new(:created_on, :sortable => "#{Issue.table_name}.created_on", :default_order => 'desc'),
     QueryColumn.new(:closed_on, :sortable => "#{Issue.table_name}.closed_on", :default_order => 'desc'),
     QueryColumn.new(:relations, :caption => :label_related_issues),
+    QueryColumn.new(:subtasks, :caption => :label_subtask_plural),
     QueryColumn.new(:description, :inline => false)
   ]
 
diff -ur -x log redmine-3.3-stable_with_long_text-20170217/app/models/issue.rb dev/app/models/issue.rb
--- redmine-3.3-stable_with_long_text-20170217/app/models/issue.rb	2017-02-17 11:23:14.000000000 +0100
+++ dev/app/models/issue.rb	2017-03-16 15:25:20.399259639 +0100
@@ -241,6 +241,7 @@
     @assignable_versions = nil
     @relations = nil
     @spent_hours = nil
+    @subtasks = nil
     @total_spent_hours = nil
     @total_estimated_hours = nil
     base_reload(*args)
@@ -1006,6 +1007,10 @@
     @spent_hours ||= time_entries.sum(:hours) || 0
   end
 
+  def subtasks
+    @subtasks ||= IssueRelation::Relations.new(self, children)
+  end
+
   # Returns the total number of hours spent on this issue and its descendants
   def total_spent_hours
     @total_spent_hours ||= if leaf?