Evaluation of newly bred stone fruit rootstock hybrids for first and second economy

The aim of this project was to assess ARC’s newly bred stone-fruit rootstock hybrids for rooting ability, to evaluate grafting compatibility with indicator scion varieties under nursery conditions and to evaluate rootstock selections planted under field conditions for production potential.

The project assessed rooting ability and graft compatibility under nursery conditions and production potential in the orchard

Nine of the nineteen ARC rootstocks were planted in a field trial in 2011 at Bien Donné Research Farm to evaluate their production potential. ‘Pioneer’ plum on two peach-almond hybrids, OSM99-2 and OSM99-3, from the nine ARC rootstocks were not significantly different from the standard plum rootstock, Marianna over four harvest seasons. From the nine selections planted at Bien Donné Research Farm, five were chosen by Culdevco and industry partners for planting at commercial farms. Trees were planted out successfully at four commercial farms in winter 2015 by Dr Piet Stassen in consultation with Culdevco, two in the Western Cape and two in the Northern Province. The sites in the Western Cape were visited in spring 2016 and a visit to the farms in the Northern Cape is planned for spring 2017.  Several ARC-bred rootstock hybrids were further evaluated for chilling requirement but the procedure that was used did not give relevant information that can be readily used by industry and as a result the procedure is under review.

Ten from the nineteen ARC-bred rootstock selections with resistances/tolerances for drought, nematodes (ring and root-knot) and high pH were found to root well and were compatible with plum and nectarine scion varieties ‘Pioneer’ and ‘Alpine’. These need to be evaluated further under field conditions to evaluate their production potential. ARC-bred rootstock selections planted at different commercial farms should be monitored closely to identify which could be valuable rootstocks to the South African stone-fruit industry.