diff --git a/conda/environment.yml b/conda/environment.yml
index aceaa5d..665eea5 100644
--- a/conda/environment.yml
+++ b/conda/environment.yml
@@ -1,5 +1,7 @@
 name: mtg_dev
 channels:
+  - openalea3/label/dev
+  - openalea3/label/rc
   - openalea3
   - conda-forge
 
diff --git a/conda/meta.yaml b/conda/meta.yaml
index 6b291b3..15eac79 100644
--- a/conda/meta.yaml
+++ b/conda/meta.yaml
@@ -20,7 +20,6 @@ build:
   noarch: python
   number: 0
   preserve_egg_dir: True
-  string: py{{ PY_VER }}
   script:
     - {{ PYTHON }} -m pip install . --no-deps --ignore-installed --no-build-isolation -vv
 
diff --git a/src/openalea/mtg/gui/mtg_editor.py b/src/openalea/mtg/gui/mtg_editor.py
index d80903f..78d920f 100644
--- a/src/openalea/mtg/gui/mtg_editor.py
+++ b/src/openalea/mtg/gui/mtg_editor.py
@@ -176,15 +176,15 @@ def notify_edge_removals(self, edges):
 ##############################################
 # -- The graphical part of the MTG editor -- #
 ##############################################
-from PyQt4 import QtGui, QtCore
+from qtpy import QtGui, QtCore, QtWidgets
 
 class Vertex( qt.DefaultGraphicalVertex ):
     max_scale = 6
 
     def __init__(self, *args, **kwargs):
         qt.DefaultGraphicalVertex.__init__(self, *args, **kwargs)
-        self.setFlag(QtGui.QGraphicsItem.ItemIsFocusable, True)
-        self._label = QtGui.QGraphicsSimpleTextItem(self)
+        self.setFlag(QtWidgets.QGraphicsItem.ItemIsFocusable, True)
+        self._label = QtWidgets.QGraphicsSimpleTextItem(self)
 
     def _mtg(self):
         return self.graph().graph
@@ -401,10 +401,10 @@ def initialise_graph_view_from_model(graphView, graphModel):
     from random import randint as rint
 
     #THE APPLICATION'S MAIN WINDOW
-    class MainWindow(QtGui.QMainWindow):
+    class MainWindow(QtWidgets.QMainWindow):
         def __init__(self, parent=None):
             """                """
-            QtGui.QMainWindow.__init__(self, parent)
+            QtWidgets.QMainWindow.__init__(self, parent)
 
             self.setMinimumSize(800,600)
             self.__graph = ObservableMTG()
@@ -413,8 +413,8 @@ def __init__(self, parent=None):
             self.setCentralWidget(self.__graphView)
 
 
-    app = QtGui.QApplication(["GraphEditor and Mtg test"])
-    QtGui.QApplication.processEvents()
+    app = QtWidgets.QApplication(["GraphEditor and Mtg test"])
+    QtWidgets.QApplication.processEvents()
     w = MainWindow()
     w.show()
     app.exec_()
diff --git a/src/openalea/mtg_wralea/gui.py b/src/openalea/mtg_wralea/gui.py
index dd532c8..0b24536 100644
--- a/src/openalea/mtg_wralea/gui.py
+++ b/src/openalea/mtg_wralea/gui.py
@@ -18,7 +18,7 @@
 from openalea.visualea.node_widget import NodeWidget
 from openalea.mtg.gui.mtg_editor import GraphicalMtgFactory, ObservableMTG
 
-from PyQt4 import QtGui
+from qtpy import QtGui
 
 class MTGEditor(QtGui.QWidget, NodeWidget):
     def __init__(self, node, parent):