diff --git a/src/MNH/mode_les_diachro.f90 b/src/MNH/mode_les_diachro.f90
index 4b9437a401d5947efbdd98f4b6e2a3b7eef99c05..0918a7266e0e3b1bf0fa36fac9c79f13e6b239ce 100644
--- a/src/MNH/mode_les_diachro.f90
+++ b/src/MNH/mode_les_diachro.f90
@@ -654,9 +654,9 @@ if ( present( htitle ) ) then
   ytitle(:) = ygroup // htitle(:)
 else
   if ( gsurf ) then
-    ytitle(1) = hgroup
+    ytitle(:) = hgroup
   else
-    ytitle(1) = ygroup
+    ytitle(:) = ygroup
   end if
 end if