Nuts of 11 Juglans species available in INRA walnut germplasm collection.

These Juglans accessions come from 23 countries covering three continents: Europe (France, Spain, Greece, Ukraine, etc.), America (Canada, USA and Chile) and Asia (China, Japan, Iran, etc.). All accessions are 20–30 year-old grafted trees on various rootstocks located in the Fruit Tree Experimental Unit (UEA) of INRA in Toulenne (latitude 44°34’37.442”N–longitude 0°16’51.48”W), near Bordeaux (France). The list of accessions studied is shown in S1 Table.