Articles
Growth of tall, unpruned bare rooted ‘Chandler’ walnut trees on clonal Paradox ‘VX211’, ‘RX1’, and ‘Vlach’ rootstock
Article number
1420_1
Pages
1 – 8
Language
English
Abstract
In California, finished bare root trees are typically delivered from the nursery around 1.8 m height.
During the first leaf, trees are trained to a single trunk.
The primary scaffolds develop during the second leaf and secondary scaffolds during the third leaf.
One-year-old nursery grown Chandler June buds on clonal rootstocks ‘VX211’, ‘RX1’, and ‘Vlach’ with large root systems were left unheaded at 2.7 m tall when they were dug and then planted in winter 2015. No heading cuts were made during the tree training years.
These tall trees produced functional primary branches during the first growing season.
By the end of the second growing season, trees had a well-developed structure much more advanced than a conventionally trained two-year old tree.
Trees were mechanically harvested and produced high yields in the third leaf, with RX1 producing significantly higher yields.
In 2019 through 2022, there were no significant yield differences between rootstocks. ‘Chandler’ on all three clonal rootstocks produced approximately 6.7 metric t ha‑1 in the sixth and eighth leaf.
There were no significant nut quality differences between the rootstocks over the years.
Rootstock circumference for ‘VX211’ was significantly greater than ‘Vlach’ which was significantly greater than ‘RX1’. ‘Chandler’ on ‘VX211’ had a significantly lower scion circumference compared to ‘Vlach’ early on but there were no differences between scion circumferences from 2020 through 2022 among the three rootstocks.
Surveys showed ‘Vlach’ with the most crown gall, ‘VX211’ as intermediate, and very low infection in ‘RX1’ rootstock.
July and October 2022 leaf samples showed trees on ‘RX1’ with significantly higher percent chloride compared to ‘VX211’ and ‘Vlach’. Using tall bare rooted trees with no heading cuts for eight years allowed earlier tree development and yields, reducing costs of orchard development while producing quicker and sustained returns.
During the first leaf, trees are trained to a single trunk.
The primary scaffolds develop during the second leaf and secondary scaffolds during the third leaf.
One-year-old nursery grown Chandler June buds on clonal rootstocks ‘VX211’, ‘RX1’, and ‘Vlach’ with large root systems were left unheaded at 2.7 m tall when they were dug and then planted in winter 2015. No heading cuts were made during the tree training years.
These tall trees produced functional primary branches during the first growing season.
By the end of the second growing season, trees had a well-developed structure much more advanced than a conventionally trained two-year old tree.
Trees were mechanically harvested and produced high yields in the third leaf, with RX1 producing significantly higher yields.
In 2019 through 2022, there were no significant yield differences between rootstocks. ‘Chandler’ on all three clonal rootstocks produced approximately 6.7 metric t ha‑1 in the sixth and eighth leaf.
There were no significant nut quality differences between the rootstocks over the years.
Rootstock circumference for ‘VX211’ was significantly greater than ‘Vlach’ which was significantly greater than ‘RX1’. ‘Chandler’ on ‘VX211’ had a significantly lower scion circumference compared to ‘Vlach’ early on but there were no differences between scion circumferences from 2020 through 2022 among the three rootstocks.
Surveys showed ‘Vlach’ with the most crown gall, ‘VX211’ as intermediate, and very low infection in ‘RX1’ rootstock.
July and October 2022 leaf samples showed trees on ‘RX1’ with significantly higher percent chloride compared to ‘VX211’ and ‘Vlach’. Using tall bare rooted trees with no heading cuts for eight years allowed earlier tree development and yields, reducing costs of orchard development while producing quicker and sustained returns.
Publication
Authors
J. Hasey, L. Milliron, C. Beumel, C. Reyes, C. Brannon, B. Lampinen
Keywords
June buds, unheaded, primary branches, crown gall, chloride
Groups involved
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