Articles
Growth of bare root June budded ‘Chandler’ walnut trees compared to potted micrografted finished trees on clonal Paradox ‘RX1’ rootstock
Article number
1420_4
Pages
25 – 32
Language
English
Abstract
California walnut growers have several nursery products for clonal rootstock including bare root or potted rootstock, or finished bare root one-year-old June buds or two-year-old nursery grafted trees.
Another option, potted finished trees that are grafted in the container (micrografts), have limited availability.
Planting bare root or potted rootstock and fall budding or grafting the following spring adds an additional year to the training, compared to finished trees where the trunk is trained during the first leaf.
An orchard planted in 2016, alternated every two rows with either bare root ‘Chandler’ June budded trees or potted ‘Chandler’ micrografted trees both on clonal Paradox ‘RX1’ rootstock, to compare growth, yield, and crown gall incidence.
Within the June bud rows was a replicated rootstock trial with ‘RX1’ as a treatment.
Growth and yield (2018-2020) on these trees were compared to adjacent micrografted ‘Chandler’ on ‘RX1’. Additionally, canopy light interception and yields were taken (2019-2022) comparing June buds to micrografts on a larger scale in the orchard.
No heading cuts were made at planting or during training.
At planting and after the first leaf, June budded rootstock was significantly larger than micrografted rootstock.
By the fourth year and continuing through year seven, both rootstock and scion on micrografts were significantly larger than on June buds.
However, fourth leaf yields were significantly higher in June budded trees.
Although there were no significant yield differences for fifth through seventh leaf, cumulative yield and yield efficiency (except 2021) were significantly greater in June budded trees.
We observed delayed catkin production in micrografted trees.
There were no significant differences in nut quality in 2022. ‘RX1’ had extremely low crown gall infection in micrografted trees.
Our results show higher vigor on potted micrografted finished trees, but lower early yield compared to bare root June budded trees.
Another option, potted finished trees that are grafted in the container (micrografts), have limited availability.
Planting bare root or potted rootstock and fall budding or grafting the following spring adds an additional year to the training, compared to finished trees where the trunk is trained during the first leaf.
An orchard planted in 2016, alternated every two rows with either bare root ‘Chandler’ June budded trees or potted ‘Chandler’ micrografted trees both on clonal Paradox ‘RX1’ rootstock, to compare growth, yield, and crown gall incidence.
Within the June bud rows was a replicated rootstock trial with ‘RX1’ as a treatment.
Growth and yield (2018-2020) on these trees were compared to adjacent micrografted ‘Chandler’ on ‘RX1’. Additionally, canopy light interception and yields were taken (2019-2022) comparing June buds to micrografts on a larger scale in the orchard.
No heading cuts were made at planting or during training.
At planting and after the first leaf, June budded rootstock was significantly larger than micrografted rootstock.
By the fourth year and continuing through year seven, both rootstock and scion on micrografts were significantly larger than on June buds.
However, fourth leaf yields were significantly higher in June budded trees.
Although there were no significant yield differences for fifth through seventh leaf, cumulative yield and yield efficiency (except 2021) were significantly greater in June budded trees.
We observed delayed catkin production in micrografted trees.
There were no significant differences in nut quality in 2022. ‘RX1’ had extremely low crown gall infection in micrografted trees.
Our results show higher vigor on potted micrografted finished trees, but lower early yield compared to bare root June budded trees.
Publication
Authors
J. Hasey, L. Milliron, C. Beumel, B. Lampinen
Keywords
nursery products, yield, crown gall, canopy light interception, no heading cuts
Groups involved
Online Articles (45)