Volume 62 Number 1 Article 1
Year 2008 Month 1
Title: Cultivar Influences Early Rootstock and Scion Survival of Grafted Black Walnut
Authors: A.L. Thomas, D.K. Brauer, T.J. Sauer, M.V. Coggeshall, M.R. Ellersieck
Abstract:
Black walnut (Juglans nigra L.) is being increasingly planted and cultivated in the midwestern USA for the
economic potential of both its wood and nuts.
Trees that are established for nut production have greater potential
for long-term productivity and profit if they are grafted to superior nut-producing cultivars.
While numerous
productive cultivars have been identified that perform well as scions, advances have not yet been made toward
developing superior black walnut rootstocks.
Furthermore, very little is known about how various black walnut
scion or rootstock cultivars may interact with each other and their environment.
The objective of this study was to
evaluate early transplant performance of black walnut scion-rootstock combinations at four sites, and to determine
which cultivars or cultivar-graft combinations may be best for successful establishment of new plantings.
A total
of 327 trees comprising 20 different black walnut scion-rootstock graft combinations transplanted at four locations
in Missouri (spring 2001) and Arkansas (fall 1999) were selected for analysis.
All trees were pre-grafted,
and consisted of potted two-year-old seedling rootstocks of known female parentage (open-pollinated seeds from
named cultivars), and one-year-old scions of superior, named nut-producing cultivars.
Rootstock and scion survival
at all sites was assessed in fall 2002. Seedlings from the cultivar ‘Kwik-Krop’ survived significantly better
as rootstocks (83%) than did seedlings from ‘Sparrow’ (51%), ‘Thomas’ (57%), and an unimproved nursery-run
rootstock (65%), but rootstock source did not affect survival of specific scion cultivars.
Among trees on surviving
rootstocks, ‘Kwik-Krop’ scions survived better (96%) than did ‘Surprise’ (79%) or ‘Emma K’ (80%) scions.
Over
the entire range of rootstocks, trees with ‘Thomas’ scions had better rootstock survival (79%) than ‘Sparrow’ (63%),
‘Kwik-Krop’ (63%), and ‘Surprise’ (53%) scions.
These results suggest that rootstock seed source is an important
consideration for successful establishment of grafted black walnut plantings, and that scion cultivar might also
influence early transplant survival.
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