U.S. patent number PP21,179 [Application Number 11/821,844] was granted by the patent office on 2010-08-03 for walnut rootstock `vx211`.
This patent grant is currently assigned to N/A, The Regents of the University of California, The United States of America, as represented by the Secretary of Agriculture. Invention is credited to Gregory Browne, Thomas Buzo, Wesley Hackett, Stephanie Kaku, Charles Leslie, Gale McGranahan, James McKenna, Michael McKenry.
United States Patent |
PP21,179 |
McGranahan , et al. |
August 3, 2010 |
Walnut rootstock `VX211`
Abstract
A new and distinct variety of walnut rootstock denominated
`VX211` is described. This new variety, `VX211`, can be propagated
through standard tissue culture micropropagation or rooted
cuttings. `VX211` has vigor and survivability in the nursery and in
the orchard. It has reduced susceptibility to damage from nematodes
(Pratylenchus vulnus) compared to other `Paradox` rootstock.
`VX211` also has reduced susceptibility to damage from Phytophthora
citricola in greenhouse screens and in the field compared to other
`Paradox` rootstock.
Inventors: |
McGranahan; Gale (Davis,
CA), Leslie; Charles (Davis, CA), Hackett; Wesley
(Davis, CA), Browne; Gregory (Davis, CA), McKenna;
James (West Lafayette, IN), Buzo; Thomas (Reedley,
CA), Kaku; Stephanie (Fresno, CA), McKenry; Michael
(Selma, CA) |
Assignee: |
The Regents of the University of
California (Oakland, CA)
The United States of America, as represented by the Secretary of
Agriculture (Washington, DC)
N/A (N/A)
|
Family
ID: |
40137937 |
Appl.
No.: |
11/821,844 |
Filed: |
June 25, 2007 |
Prior Publication Data
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|
Document
Identifier |
Publication Date |
|
US 20080320618 P1 |
Dec 25, 2008 |
|
Current U.S.
Class: |
PLT/154 |
Current CPC
Class: |
A01H
5/08 (20130101); A01H 6/54 (20180501) |
Current International
Class: |
A01H
5/00 (20060101) |
Field of
Search: |
;PLT/154 |
Other References
McGranahan, Gale. Nurseries Licensed to Sell New Clonal Walnut
Rootstocks. Walnut Improvement Program, UC Davis. May 1, 2008.
Available at: http://cesutter.ucdavis.edu/files/51594.pdf. cited by
examiner .
McGranahan, G. et al. (1996). "The Paradox Diversity Study," Walnut
Research Reports 1996, pp. 43-48. cited by other .
Browne, G.T. et al. (1998). "Strategies for Control of Phytophthora
Root and Crown Rots of Walnut," Walnut Research Reports 1997, pp.
381-391. cited by other .
McGranahan, G. et al. (1998). "The Paradox Diversity Study," Walnut
Research Reports 1997, pp. 55-63. cited by other .
Browne, G.T. et al. (1999). "Strategies For Control of Phytophthora
Root and Crown Rots of Walnut," Walnut Research Reports 1998, pp.
361-371. cited by other .
McKenna, J. et al. (1999). "The Paradox Genetic Diversity Study,"
Walnut Research Reports 1998, pp. 40-65. cited by other .
Browne, G. (2001). "Strategies for Management of Phytophthora on
Walnut: Evaluating Potential of Elite Paradox Clones and Wingnut
Families," Walnut Research Reports 2000, pp. 429-436. cited by
other .
McKenry, M. et al. (2001). "A Three-Year Search for Nematode
Resistance in Walnut-Final Report," Walnut Research Reports 2000,
pp. 509-512. cited by other .
Browne, G. (2002). "Strategies for Management of Phytophthora on
Walnut: Evaluating Potential of Elite Paradox Clones and Wingnut
Families," Walnut Research Reports 2001, pp. 101-109. cited by
other .
Hackett, W.P. et al. (2003). "Propagation and Retesting of Walnut
Rootstock Genotypes Putatively Resistant to Pests and Diseases,"
Walnut Research Reports 2002, pp. 99-107. cited by other .
Browne, G.T. et al. (2004). "Evaluation of Resistance to
Phytophthora citricola Among Diverse Clones of Paradox Hybrid
Rootstocks," Proceedings of the Vth International Walnut Symposium,
Sorrento, Italy, pp. 395-405. cited by other .
Hackett, W.P. et al. (2004). "Propagation and Retesting of Walnut
Rootstock Genotypes Putatively Resistant to Pests and Diseases,"
Walnut Research Reports 2003,pp. 85-95. cited by other .
McKenry, M. (2004). "Field Evaluations/Inputs for Grower Replant
Settings and New Lines of Nematode Resistance," Walnut Research
Reports 2003, pp. 431-439. cited by other .
Browne, G. et al. (2005). "Determining Phytophthora Resistance in
Elite Paradox Clones and Specific Etiology of a Paradox Crown and
Root Rot," Walnut Research Reports 2004, pp. 379-387. cited by
other .
Hackett, W.P. et al. (2005). "Propagation and Retesting of Walnut
Rootstock Genotypes Putatively Resistant to Pests and Diseases,"
Walnut Research Reports 2004, pp. 89-95. cited by other .
McKenry, M. (2005). "Field Evaluations/Inputs for Grower Replant
Settings and New Lines of Nematode Resistance," Walnut Research
Reports 2004, pp. 407-415. cited by other .
McKenry, M. (2006). "Field Evaluations/Inputs for Grower Replant
Settings and New Lines of Nematode Resistance," Walnut Research
Reports 2005, pp. 365-371. cited by other .
McGranahan, G. et al. (2006). "Clonal Propagation of Walnut
Rootstock Genotypes for Genetic Improvement," Walnut Research
Reports 2005, pp. 85-93. cited by other .
Browne, G. et al. (2006). "Biology and Management of Phytophthora
Crown and Root Rot of Walnut," Walnut Research Reports 2005, pp.
335-344. cited by other .
McKenry, M. (2007). "Filed Evaluations/Inputs for Grower Replant
Settings and New Lines of Nematode Resistance," Walnut Research
Reports 2006, pp. 279-283. cited by other .
Grant, J. et al. (2007). "Orchard Performance of Selected Clonal
Paradox Rootstocks," Walnut Research Reports 2006, pp. 79-81. cited
by other .
McGranahan, G. et al. (2007). "Clonal Propagation of Walnut
Rootstock Genotypes for Genetic Improvement 2006," Walnut Research
Reports 2006, pp. 71-78. cited by other .
Browne, G. T. et al. (1999-2000). Project Plan/Research Grant
Proposal for Year 4 of 5 of "Strategies for Control of Phytophthora
Root and Crown Rots of Walnut," University of California Division
of Agricultural Sciences, 6 pages. cited by other .
Browne, G. T. et al. (2004-2005). Project Plan/Research Grant
Proposal for Year 1 of 2 of "Determining Phytophthora Resistance in
Elite Paradox Clones and Specific Etiology of a Paradox Crown and
Root Rot," University of California Division of Agricultural
Sciences, 5 pages. cited by other.
|
Primary Examiner: Haas; Wendy C
Attorney, Agent or Firm: Morrison & Foerster LLP
Claims
What we claim is:
1. A new and distinct variety of walnut rootstock plant designated
`VX211` as shown and described herein.
Description
Latin name: Botanical/commercial classification: (Juglans
hindsii.times.Juglans regia)/new `Paradox` walnut rootstock.
Varietal denomination: The varietal denomination of the claimed
walnut rootstock is `VX211`.
BACKGROUND OF INVENTION
The present invention relates to a new and distinct clonal
rootstock of `Paradox` (not patented) walnut tree (Juglans
hindsii.times.Juglans regia) that has been denominated varietally
as `VX211`, and more particularly to such a walnut rootstock that
is vigorous, that has reduced susceptibility to nematodes
(Pratylenchus vulnus) and Phytophthora (Phytophthora citricola),
and that further is easily clonally propagated by standard tissue
culture micropropagation.
It has long been recognized as desirable to provide vigorous walnut
rootstocks that have increased resistance to soil pests and
diseases, specifically nematodes (Pratylenchus vulnus) and
Phytophthora (Phytophthora citricola). The rootstock of the present
variety, `VX211`, is similar to other `Paradox` walnut rootstocks
(Juglans hindsii.times.Juglans regia), except that it has increased
resistance or tolerance to Pratylenchus vulnus and Phytophthora
citricola and can be easily micropropagated to produce a vigorous
clonal `Paradox` rootstock.
SUMMARY OF THE INVENTION
It was found that the walnut rootstock `VX211` of the present
invention exhibits the following combination of characteristics: a)
can be propagated through standard tissue culture micropropagation
or rooted cuttings; b) has vigor and survivability in the nursery
and in the orchard; c) has reduced susceptibility to damage from
nematodes (Pratylenchus vulnus) compared to other `Paradox`
rootstock; an d) has reduced susceptibility to damage from
Phytophthora citricola in greenhouse screens and in the field
compared to other `Paradox` rootstock.
BRIEF DESCRIPTION OF THE TABLES
Table 1 shows comparative nursery performance of `VX211` and other
walnut rootstock clones.
Table 2 shows growth rating and diameters for `VX211` and other
rootstock clones.
Table 3 shows field performance of clonal `Paradox` walnut hybrids,
Northern California black walnut and Chinese wingnut rootstocks in
non-infested soil and soil infested with Phytophthora.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows performance of `VX211` compared to `AX1` under
pressure from nematodes at varying densities.
FIG. 2 shows a visual rating of tree growth and condition of clonal
and seedling test trees at a Jenny Lind, Calif. field site.
FIG. 3 shows cumulative percent mortality of clonal and seedling
test trees at a Jenny Lind, Calif. field site.
FIG. 4 shows tree mortality of clonal and seedling test trees at a
Linden, Calif. field site.
FIG. 5 shows relative resistance to Phytophthora citricola among
clonal and seedling test trees in greenhouse experiment.
FIG. 6 shows `VX211` at 10 years of age.
FIG. 7 shows bark of ten-year old `VX211`.
FIG. 8 shows several three-year old trees of `VX211`.
FIG. 9 shows bark at base of three-year old `VX211`.
FIG. 10 shows bark and lenticels farther up the stem of
`VX211`.
FIG. 11 shows 6-month old greenhouse grown `VX211`.
FIG. 12 shows grafted `VX211`.
FIG. 13 shows spring foliage of `VX211`.
FIG. 14 shows deep red of new foliage of `VX211`.
FIG. 15 shows upper side of mature leaf of `VX211`.
FIG. 16 shows lower side of mature leaf of `VX211`.
DETAILED DESCRIPTION OF THE INVENTION
The new rootstock of the present invention was selected as part of
the "Paradox Diversity Study" (PDS) which was initiated in 1996 to
study the genetic diversity of commercial `Paradox` sources. The
study included approximately 300 500 seeds each (depending on the
predicted percent `Paradox`), from 37 black walnut sources of
`Paradox` provided by California walnut nurseries, and seven
controlled crosses made in Davis, Calif. and open-pollinated
controls from different Juglans species. Seeds were germinated and
grown at 3 different nurseries for one year and then seedlings were
distributed to cooperating researchers for tests of response to
nematodes, Phytophthora (seed supplied), crown gall (Agrobacterium
tumefaciens) and the field environment (field trials). The study
was repeated in 1997.
The rootstock of the present invention was evaluated for response
to nematodes in 1998 along with 9 siblings and the remaining
rootstock families. One-year old seedlings were planted on 1.2 or
1.8 meter spacing with 3.35 meter centers. The field test site was
infested with a single population of root lesion nematode (P.
vulnus) originally placed on site in 1976. At planting time
seedlings were inoculated with additional P. vulnus. Each fall 20
grams of root tissue were collected from each tree. These roots
were placed in a mist chamber for 5 days for nematode extraction
and nematodes/gram root was calculated.
In July 1998 it was evident that one seedling (`VX211`) was more
vigorous than the others, but in the fall the nematodes were
abundant on the roots of `VX211`. In July 1999 roots were collected
and again nematodes were found to be abundant, but the seedling
`VX211` continued to be more vigorous than the other seedlings in
spite of the nematodes. Due to its apparent superiority it was
transplanted to a "mother block" at an agriculture center in
Parlier, Calif. In winter 2000 2001 propagating wood was collected.
`VX211` was propagated by hardwood cuttings. Additionally, `VX211`
was asexually reproduced by standard tissue culture
micropropagation in Davis, Calif. In 2002 a "stock block" was
established in Davis, Calif. with 6 trees of `VX211` as well as
other promising selections.
Propagation of `VX211` both by standard hardwood cuttings and by
standard tissue culture micropropagation was successful. From
November 2002 to October 2003, 212 `VX211` plants were
micropropagated, rooted in gelled medium and acclimatized in the
greenhouse; 153 (72%) survived. When rooted ex vitro, 126/184 (68%)
survived. Hardwood cuttings rooted between 73% (11/15) to 87%
(13/15). By November 2003 there were 187 available for field trials
and 60 available for Phytophthora screening.
In March 2004, 48 plants of the `VX211` clone and a standard
`Paradox` (`AX1`) were evaluated for additional nematode screening
and comparison. These were planted in 1/100.sup.th acre macroplots.
The macroplots had concrete sides 1.5 meter deep into the soil with
open bottoms and were nematode-free. `VX211` and `AX1` were planted
side by side in 48 separate macroplots infested with 0, 1, 20, or
500 P. vulnus nematodes per 250 cc of soil. Tree diameters and
number of nematodes on the roots were determined 2004 2006 (FIG.
1). Nematodes built up quickly but `VX211` was 30% taller in the
first year and the diameter of `VX211` was significantly greater
than `AX1` in all three years (FIG. 1). The vigor of `VX211` under
pressure from nematodes suggests that `VX211` has a means to avoid
or escape severe damage from nematodes.
In spring 2004, 106 plants of `VX211` produced through standard
tissue culture micropropagation were planted in a nursery along
with over 1800 plants of 17 different clones. At the end of the
growing season `VX211` was the most vigorous of all clones (Table
1) demonstrating that propagation is true-to-type through
successive generations. Eighty-two percent were graftable and the
mean diameter was 31 mm at 5 cm from the soil surface.
Graftable trees were distributed for grafted field trials in 5
different orchards in replant situations in 2005. Grafting posed no
problem and `VX211` is considered compatible with English walnut
scions. It is a typical `Paradox` in that respect. In addition, 30
each of 11 different genoptypes including `VX211` were planted in
May 2005 in Davis, Calif. for artificial inoculation with
Phytophthora citricola. A randomized block split plot design was
used. For each rootstock clone, there were six four-tree plots to
be infested and six single-tree plots to serve as non-infested
controls. Northern California black (Juglans hindsii) and wingnut
(Pterocarya stenoptera) were included as susceptible and resistant
controls, respectively. In January 2006, 100 ml of a V8 juice-oat
mixture infested with Phytophthora citricola was mixed into the
upper 5 cm of soil around the trunk of each tree. A sterile mixture
was applied to the uninoculated controls.
Early results from several of the grafted field trials are shown
(FIGS. 2 4; Table 2). In all cases `VX211` was one of the superior
clones. The block artificially inoculated with Phytophthora was
assessed for growth in trunk circumference and development of crown
rot as indicated by trunk cankers extending up from the soil
surface in November 2006. Sixty-two percent of the susceptible
controls were rotted or dead. The uninoculated controls of `VX211`
were the most vigorous trees in the block apart from the wingnut
controls. No cankers were found on `VX211` or many of the other
clones, however the Phytophthora inoculation did appear to depress
growth somewhat in `VX211` (Table 3).
Simultaneously with field trials, greenhouse trials were carried
out to assess the relative susceptibility of `VX211` and other
selected clones to Phytophthora citricola. Standard Phytophthora
screening methods were used. Clonal selections including `VX211`
were micropropagated, rooted, acclimatized and chilled, and at 2 6
months were transplanted to pots of artificially inoculated soil.
Four isolates of P. citricola from different districts of
California were used to infest the soil. The isolates were grown in
separate jars of V8 juice-oat-vermiculite substrate for one month,
mixed in equal proportions and mixed in the soil (40 ml inoculated
substrate per liter of soil). Starting two weeks after
transplanting, all plants received 48-hour periods of soil flooding
every two weeks. Three months after transplanting, soil was washed
from the plants and the incidence and severity of crown rot were
determined. One selected clone, `VX211` consistently showed
moderate resistance. The results from 2006 trials are shown in FIG.
5.
BOTANICAL DESCRIPTION OF THE PLANT
This description is based on the original selection of `VX211`,
ungrafted, at ten years of age, a 3-year old ungrafted tree in
Phytophthora field screen, and a greenhouse-grown plant at 6 months
of age. Figures are also shown of a grafted `VX211` tree. Data for
the botanical description were collected in spring 2007.
The Munsell Color Charts for Plant Tissues (1977. GretagMacbeth,
New Windsor N.Y.) is used in the identification of color. Also,
common color terms are to be accorded their ordinary dictionary
significance, Botanical classification: Juglans
hindsii.times.Juglans regia. Female parent: Juglans hindsii. Male
parent: Juglans regia.
`VX211` differs from its female parent by having fewer
leaflets/leaf, broader leaflets and hybrid vigor. `VX211` differs
from its male parent by having more leaflets/leaf and hybrid vigor.
`VX211` does not differ substantially from other similar hybrids
except in its superior performance under adverse soil conditions as
described in the "Background of the Invention". Plant: The growth
habit of the tree is illustrated in FIG. 6. This 10 year old tree
is approximately 7.3 meters in height with a canopy diameter of
approximately 5 meters. The trunk circumference at 1.2 meters above
ground level is about 0.61 meters. The bark and year-old branches
are light brown (2.5Y 7/2) (FIG. 7). New shoots are green (5GY
7/6). Lenticels (approximately 12 per 2.5 square cm) are slightly
lighter than the bark (2.5Y 8/2). The 3 year old trees are 4.3 4.9
meters tall (FIG. 8). The bark is brownish-green (2.5GY 5/8) with
scattered (22/2.5 square cm.) buff-colored lenticels (7.5YR 8/2)
(FIGS. 9, 10). The six month old greenhouse grown tree is about 35
cm. tall and the main stem is about 1 cm. in diameter (FIG. 11) and
green (5GY/10). Lenticels about 0.5 mm long are more dense at the
base of the plant and are a buff color (2.5Y 8/4). Graft take is in
the normal range for seedling `Paradox` walnuts (FIG. 12). Foliage:
The slightly pubescent new spring foliage has a reddish hue to it
(10R 4/8), darkest towards the tip (FIGS. 13 and 14) turning green
(5GY 5/6) as the leaves get older. The leaves are smooth and the
margins are entire (not serrate). The leaves are pinnately compound
with 13 15 leaflets. The mature leaves of the 6 month old plant
have 9 11 leaflets and are 30 cm long and 23 cm wide. The number of
leaflets may vary depending on the age and size of the plant. The
upper leaf surface is bright green and the same color as the stem
(5GY 5/10) (FIG. 14). The lower surface is slightly duller (5GY
6/6) (FIG. 16). The leaflets are about 5 cm wide and 14 cm long
with a petiole 4 8 cm long. Inflorescence: No catkins or female
flowers appeared in the first 10 years. The tree is probably male
sterile as is typical with Juglans hindsii.times.Juglans regia
hybrids. No nuts were observed. Disease resistance and
susceptibility: This rootstock is typical of other Juglans
hindsii.times.Juglans regia hybrids except that it possesses higher
vigor and ability to survive heavy nematode loads. It is also less
susceptible to Phytophthora citricola than other similar hybrids.
Usage: The new rootstock of the present invention provides walnut
growers with a new clonally propagated `Paradox` rootstock. It can
be easily micropropagated.
TABLE-US-00001 TABLE 1 Clones grown in Stanislaus County,
California in 2004 Graft- Graft- Planted able able Diameter (mm)
Clone N N % Mean SD Range CV Nematodes VX211 106 87 82 31 4.9 21-44
12.6 Phytophthora AZ2 230 151 66 26 5 13-38 19.2 AZ3 49 24 49 25
6.7 11-37 26.8 NZ1 172 111 64 26 4.4 10-39 16.9 JX2 246 191 78 29
4.1 13-39 14.1 RX1 104 78 75 18 1.6 14-22 8.8 AX1 163 86 53 27 4.3
14-40 15.9 GZ1 108 83 77 26 5.4 13-40 20.8 Px1 247 154 62 26 4.6
12-40 17.7 AZ1 52 38 73 30 4.4 22-43 14.7 UX1 27 23 85 25 4 15-30
16 GZ2 47 38 81 26 4.5 15-33 17.3 Blackline WIP3 158 66 42 26 5
12-35 19.2 WIP2 10 6 60 25 2.3 23-99 9.2 Control UX022 71 59 83 23
3.7 14-29 16.1 English Vina 14 10 71 18 3.7 13-24 20.5 Sunland 64
20 31 26 3.8 18-31 14.6 Totals 1868 1225 66 25
TABLE-US-00002 TABLE 2 Walnut Rootstock Orchard Trials-Yuba County.
Established May 2005. Randomized complete block design with 4
clonal and 1 seedling `Paradox` rootstock. Twelve single tree
replicates. All rootstocks generally grew well except AZ2. Midday
stem water potential measurements suggest that replants and
adjacent orchard trees were generally in a similar range to the
replants. AZ2 did not grow well despite having midday stem water
potentials in a similar range to adjacent trees and the other
replants. There was 100% survival of all replant sources. June
December November % Change 2005 June 2005 2005 2006 (June 2005
Growth Diameter Diameter Diameter to November Treatment Rating*
(mm) (mm) (mm) 2006) VX211 3.0 29.0 31.2 42.5 a +46.6 AZ2 2.0 26.9
28.5 26.2 c -2.6 NZ1 2.9 23.5 25.8 35.6 b +51.4 JX2 2.2 23.7 26.4
35.2 b +48.5 CONTROL 1.4 20.5 22.4 .sup. 30.0 bc +46.3 *rootstocks
were headed near or below 2005 diameter measurement point. 2006
measurement is on new shoot growing above previous cut. *Growth
rating descriptions: 0 No growth 1 Just breaking 2 Moderate growth
3 Vigorous growth
TABLE-US-00003 TABLE 3 Field performance of clonal `Paradox` walnut
hybrids, Northern California black walnut and Chinese wingnut
rootstocks in non-infested soil and soil infested with
Phytophthora. Clone Maternal background (or of hybrid (or Soil
treatment Incidence of species) species of standard) (January 2006)
crown rot (%) AX1 californica Control 0 c P. citricola 4 c AZ2
(major x hindsii)x nigra Control 0 c P. citricola 0 c NZ1 (major x
hindsii)x nigra Control 0 c P. citricola 0 c GZ1 hindsii Control 0
c P. citricola 4 c JX2 hindsii Control 0 c P. citricola 0 c PX1
hindsii Control 0 c P. citricola 8 bc VX211 hindsii Control 0 c P.
citricola 0 c RX1 microcarpa Control 0 c P. citricola 0 c WIP3
hindsii x regia Control 0 c P. citricola 8 bc (NCB) (J. hindsii)
Control 16 b P. citricola 62 a (Wing- (Pt. stenopiera) Control 0 c
nut) P. citricola 0 c Clone Percent of Incidence of Increase in (or
trunk circ. tree mortality trunk circ. species) Necrotic (%) (mm)
AX1 0 c 0 c 163 c 1 c 0 c 146 cde AZ2 0 c 0 c 116 fg 0 c 0 c 117 fg
NZ1 0 c 0 c 116 fg 0 c 0 c 130 def GZ1 0 c 0 c 157 cd 1 c 0 c 150
cd JX2 0 c 0 c 166 bc 0 c 0 c 135 def PX1 0 c 0 c 169 bc 1 c 0 c
157 cd VX211 0 c 0 c 191 b 0 c 0 c 147 cde RX1 0 c 0 c 112 fg 0 c 0
c 116 fg WIP3 0 c 0 c 100 g 2 c 0 c 121 efg (NCB) 17 b 17 b 65 h 59
a 59 a 57 h (Wingnut) 0 b 0 c 226 a 0 b 0 c 193 b .sup.1All trees
were planted May 2005. The assessments of crown rot and mortality
were made 21 Nov. 2006. Means within a column and without letters
in common are significantly different (Waller k ratio).
* * * * *
References