On the 25th May 2017 the ABA hosted the inaugural field day at Lacton Pty Ltd, Lindsay Point looking at the almond rootstock trial. The rootstock trial was planted in 2013 to look at new and existing rootstocks in Australia that are suitable for Prunus species but have not been tested or used for almonds. The 3.7Ha trial was established as a randomised, replicated trial meaning that the 15 treatments (rootstocks) were reproduced in a random manner to account for variability in soils and irrigation system performance. The rootstocks were grafted to 50% Nonpareil, 25% Peerless and 25% Carmel.
The aim of the rootstock trial is to investigate the potential of new rootstocks to replace Nemaguard in a replant situation and in general, more efficient use of water, nutrition and increased yield capacity. Most are Peach X Almond hybrids, while a few include Plum in their breeding which provides some tolerance to heavy soils and root asphyxia. Most are tolerant of calcareous soils and some are better in regards to pathogen resistance. An earlier glasshouse trial looked at the tolerance of Prunus rootstocks to root-knot nematodes. More information on the results of this trial can be found on the ABA website in the fact sheet titled ‘Tolerance of almond rootstocks to root-knot nematodes’.
Yields have been collected for the past two seasons and a summary was presented at the field day. For the 2016 harvest (hand harvested) the top three rootstocks were GF677 followed by the two Nemaguard treatments. In the recent 2017 harvest (machine harvested) the top three rootstocks were Monegro, Garnem and Bright’s Hybrid. Little can be concluded from the initial yields as the tree vigour needs to be considered i.e. did a poor yielding rootstock perform better this year? These questions will be answered in the future as further yield results are collected and matched with the tree circumference which is recorded each winter. Whilst some early results from the trial can be reported, they should be interpreted with caution until more data is collected and a robust statistical analysis conducted.