The Department of Mediterranean Trees at the Institut de Recerca i Tecnologia Agroalimentaries (IRTA) in Spain initiated a research program in 1993 to examine the variability among walnut species for wood production and to establish orchards with improved selections. The main objective of the programme is to obtain superior Persian walnut (Juglans regia
L.) selections, half-sib progenies or clones, for wood production. Another important goal is to use controlled crosses among different walnut species to produce new hybrids, especially Persian x black (J. nigra
L.) for wood production adapted to Spain's Mediterranean climate.
Aletà, Neus 2004. Current research in Spain on walnut for wood production. In: Michler, C.H.; Pijut, P.M.; Van Sambeek, J.W.; Coggeshall, M.V.; Seifert, J.; Woeste, K.; Overton, R.; Ponder, F., Jr., eds. Proceedings of the 6th Walnut Council Research Symposium; Gen. Tech. Rep. NC-243. St. Paul, MN: U.S. Department of Agriculture, Forest Service, North Central Research Station. 153-155