WALNUT ROOTSTOCK SELECTION FOR CALCAREOUS SOILS IN SOUTHEASTERN AUSTRALIA AND THE POTENTIAL FOR EXPANDING THE WALNUT INDUSTRY IN THE REGION

Persian walnuts are grown over relatively small area within irrigated settlements of the Murray Lowlands Province of Southeastern Australia compared with traditional crops such as grapes and citrus or emerging crops such as almonds.
Poor walnut tree health usually associated with wrong rootstock selection, or growth in areas with inadequate topsoil depth, have inculcated a strong traditional resistance amongst growers and horticultural developers to walnuts as a viable alternative crop for the region.
Recent trials comparing Juglans hindsii, a traditional rootstock for the area, with a new selection of Paradox rootstock, have shown the Paradox ‘entity’ significantly outperforms J. hindsii in terms of scion growth in the first year.
The Paradox hybrid has also been shown to grow vigorously in soils with shallow topsoil depth above calcareous B horizon subsoils.
This suitability of the Paradox hybrid to calcareous soils provides the potential to expand the walnut industry into parts of the Murray Lowland Province characterized by Calcarosol soils with as little as 30 cm topsoil.

VII International Walnut Symposium

I.R.K. Sluiter, L. McKenzie, J.R. Mitchell

calcareous soils, Australia, Juglans regia, Juglans hindsii, Juglans nigra, Paradox

https://doi.org/10.17660/ActaHortic.2014.1050.12