U.S. patent number PP32,461 [Application Number 16/602,129] was granted by the patent office on 2020-11-17 for corylus plant named `hunterdon`.
This patent grant is currently assigned to Rutgers, The State University of New Jersey. The grantee listed for this patent is RUTGERS, THE STATE UNIVERSITY OF NEW JERSEY. Invention is credited to John M. Capik, Shawn A. Mehlenbacher, Thomas J. Molnar.
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United States Patent |
PP32,461 |
Molnar , et al. |
November 17, 2020 |
Corylus plant named `Hunterdon`
Abstract
A new and distinct Corylus avellana plant named `Hunterdon`
characterized by a vigorous and upright growth habit, the
production of nuts with globular kernels that fall free of the husk
at maturity, and a high level of tolerance (quantitative
resistance) to eastern filbert blight caused by the fungus
Anisogramma anomala (Peck) E. Muller.
Inventors: |
Molnar; Thomas J. (East
Brunswick, NJ), Mehlenbacher; Shawn A. (Corvallis, OR),
Capik; John M. (Somerset, NJ) |
Applicant: |
Name |
City |
State |
Country |
Type |
RUTGERS, THE STATE UNIVERSITY OF NEW JERSEY |
New Brunswick |
NJ |
US |
|
|
Assignee: |
Rutgers, The State University of
New Jersey (New Brunswickk, NJ)
|
Family
ID: |
73263781 |
Appl.
No.: |
16/602,129 |
Filed: |
August 12, 2019 |
Current U.S.
Class: |
PLT/152 |
Current CPC
Class: |
A01H
6/00 (20180501); A01H 5/08 (20130101) |
Current International
Class: |
A01H
5/08 (20180101); A01H 6/00 (20180101) |
Field of
Search: |
;PLT/152 |
Other References
http://thescalepit.com/ContentHN/Hazel%20Dormancy%20and%20Pollination.pdf;
Apr. 8, 2019; 9 pages. cited by examiner.
|
Primary Examiner: Bell; Kent L
Attorney, Agent or Firm: Daugherty; Patrick J. Daugherty
& Del Zoppo Co., LPA
Claims
What is claimed is:
1. A new and distinct cultivar of Corylus plant named `Hunterdon`,
as illustrated and described.
Description
Latin name: Corylus avellana cultivar.
Variety denomination: `Hunterdon`.
BACKGROUND OF THE INVENTION
The present Invention relates to a new and distinct cultivar of
Corylus plant, botanically known as Corylus avellana, and the
designation `Hunterdon`, or as `Hunterdon` Hazelnut (H3FR04P42
Rutgers 6), and hereinafter referred to by the name
`Hunterdon`.
The new Corylus resulted from a controlled cross of the female
parent `Sacajawea` (unpatented, Mehlenbacher et al., 2008) with
pollen of OSU 616.055 (unpatented) made in 2004. Hybrid seeds
resulting from the cross were harvested in August 2004. They were
provided a period of moist chilling, subsequently germinated, and
the seedlings were grown in the greenhouse during the summer of
2005. From this cross, a total of 106 seedling trees were planted
in a research field in East Brunswick, N.J., in October 2005.
`Hunterdon` was discovered and selected as a single plant within
that progeny of the stated cross-pollination. It was originally
assigned the designation H3FR04P42, which indicates the field, row,
and tree location of the original seedling.
The female parent `Sacajawea` was developed at Corvallis, Oreg. and
is characterized by excellent kernel quality and tolerance to
eastern filbert blight (EFB) caused by the fungus Anisogramma
anomala (Peck) E. Muller. The male parent OSU 616.055 is an
unreleased seedling that also exhibits tolerance to EFB.
`Hunterdon` was asexually reproduced by rooted suckers and whip
grafting in 2010 through 2015 in East Brunswick and New Brunswick,
N.J. The unique features of this Corylus are stable and reproduced
true-to-type in successive generations of asexual reproduction.
BRIEF SUMMARY OF THE INVENTION
The following traits have been observed and are determined to be
the unique characteristics of `Hunterdon`. These characteristics in
combination distinguish `Hunterdon` as a distinct cultivar:
Vigorous and upright-spreading plant habit.
Yellowish-green to green color of developing and fully expanded
leaves during the spring and summer.
High level of tolerance (quantitative resistance/horizontal
resistance) to eastern filbert blight (EFB) caused by the fungus
Anisogramma anomala (Peck) E. Muller. The source of this resistance
differs from the single dominant allele conferred from `Gasaway`
(unpatented, Mehlenbacher et al., 1991), which protects Corylus
avellana `McDonald` (U.S. Plant Pat. No. 28,200 P3, Mehlenbacher et
al., 2016), `Wepster` (U.S. Plant Pat. No. 27,141 P3, Mehlenbacher
et al., 2014), `Dorris` (U.S. Plant Pat. No. 25,022 P3,
Mehlenbacher et al., 2013), `Jefferson` (unpatented, Mehlenbacher
et al., 2011a), `Yamhill` (unpatented, Mehlenbacher et al., 2009),
and several other Corylus avellana cultivars and pollenizers known
to the Inventors.
Expression of incompatibility alleles S1 and S3 in the styles.
Kernels that blanch very well and have an excellent flavor after
roasting.
Comparisons in several replicated plantings in East Brunswick,
N.J., show that plants of `Hunterdon` differed from plants of the
Corylus avellana cultivar `Barcelona` (unpatented), `Tonda di
Giffoni` (unpatented), `Yamhill`, `Jefferson`, and other cultivars
and selections of Corylus avellana known to the Inventors,
primarily in their response to EFB present in New Jersey, a region
where the pathogen is native and highly genetically diverse
(Muehlbauer et al., 2019). They also differed in S-alleles, nut
size, kernel percentage (ratio of kernel weight to nut weight),
frequency of defects (blank nuts, moldy kernels, twin kernels,
etc.), time of pollen shed, and length of the husk or involucre.
`Hunterdon` is immediately distinguished from its parents by its
incompatibility allele (S-allele) combination. `Hunterdon`
expresses S-alleles S1 and S3 in its stigmas whereas `Sacajawea`
expresses S1 and S22 and OSU 616.055 expresses S3 and S12.
`Hunterdon` also differs in its response to the disease eastern
filbert blight (EFB) caused by Anisogramma anomala. Both
`Sacajawea` and OSU 616.055 express a similar moderate level of
tolerance to EFB. For example, previous studies showed `Sacajawea`
exposed to EFB resulted in an average proportion of diseased wood
of 21.0% (total length of EFB-diseased stems per tree divided by
total length of shoot growth) (see [0142] Capik, J. M. and T. J.
Molnar. 2012. Assessment of host (Corylus sp.) resistance to
eastern filbert blight in New Jersey. J. Amer. Soc. Hort. Sci.
137:157-172). `Hunterdon` has been shown to be highly tolerant
expressing an average of only 2.2% diseased wood. `Monmouth` has
been shown to be highly tolerant expressing an average of only 1.8%
diseased wood.
For example:
Eastern filbert blight response in New Jersey: In a multi-year
trial in East Brunswick, N.J., the proportion of EFB-diseased wood
across the canopy for `Hunterdon` was 2.2% compared to 20.4% for
`Yamhill`, 31.2% for `Jefferson`, 48.6% for `Gasaway`, and 67.0%
for `Barcelona`.
Pollen shed: `Hunterdon` sheds pollen in East Brunswick, N.J., with
`Yamhill` and `Santiam` (unpatented, Mehlenbacher et al., 2007),
after `Ratoli` (unpatented, minor cultivar from Tarragona, Spain),
and prior to `Jefferson` and `Gasaway`. `Hunterdon`
descriptor=5.
Husk Length: `Hunterdon` is 1.5 times nut length, like `Barcelona`,
while `Wepster` is 2.0 times the nut length.
`Hunterdon` produces kernels that are well-suited for the blanched
kernel market for use in confections and baked goods. `Hunterdon`
combines very high levels of tolerance to eastern filbert blight
(evaluated against Anisogramma anomala strains present in New
Jersey, US) with globular nuts and kernels and excellent kernel
blanching after roasting. The tree is vigorous with an upright
branching habit that produces a desirable orchard tree when pruned
to a single stem.
Field observations in East Brunswick, N.J., and results from
greenhouse-based inoculations performed in New Brunswick, N.J.,
indicate that `Hunterdon` expresses a high level of tolerance to
eastern filbert blight (EFB) caused by the fungus Anisogramma
anomala. While the cultivar is not immune to EFB, it rarely
produces stem cankers and those that develop are typically small in
size and lack fully formed reproductive stromata which show limited
sporulation, equating to very little to no stem dieback and a
greatly reduced canopy inoculum load even when infections are
present. The high level of tolerance (horizontal resistance) is
conferred by both of its unrelated, EFB-tolerant parent trees,
which is unlike the cultivars currently grown in Oregon and
Washington protected by the single dominant `Gasaway` resistance
allele. EFB is now present throughout the Willamette Valley of
Oregon where 99% of the US hazelnut crop is grown and is endemic to
the eastern US and southern Canada, where it has been historically
impossible to grow Corylus avellana commercially. `Hunterdon` was
selected in central New Jersey and is adapted to the climate
present in this region. Pruning to remove cankers and fungicide
applications are currently used to manage the disease in orchards
of `Barcelona` and other susceptible cultivars in the Pacific
Northwestern US. `Hunterdon` is suitable for planting in areas with
high EFB disease pressure. It has shown excellent tolerance in the
eastern US where the EFB fungus is native and genetically diverse
(Muehlbauer et al., 2019).
BRIEF DESCRIPTION OF THE DRAWINGS
The figures include color photographic illustrations that
illustrate the overall appearance of the new cultivar, showing the
colors as true as it is reasonably possible to obtain in colored
reproductions of this type. Foliage colors in the photographs may
differ slightly from the color values cited in the detailed
botanical description which accurately describe the colors of the
new Corylus.
FIG. 1 is a color photographic illustration of a tree of the new
cultivar `Hunterdon` hazelnut in the sixth leaf pruned to a single
stem.
FIG. 2 is a color photographic illustration of nuts, husks and
leaves of the `Hunterdon` hazelnut.
FIG. 3 is a color photographic illustration of nuts, cracked
shells, raw kernels, and blanched kernels of hazelnuts of the
`Hunterdon`.
FIG. 4 is a phenology chart illustration that shows times of female
receptivity, pollen shed, and vegetative budbreak of `Hunterdon`
and other hazelnut cultivars.
FIG. 5 is another phenology chart illustration that shows times of
female receptivity, pollen shed, and vegetative budbreak of
`Hunterdon` and other hazelnut cultivars.
DETAILED BOTANICAL DESCRIPTION
The cultivar `Hunterdon` has not been observed under all possible
environmental conditions. The phenotype may vary somewhat with
variations in environment such as temperature and light intensity,
without, however, any variance in genotype.
The figures of the present application and the following
observations and measurements describe plants grown in East
Brunswick, N.J., under commercial practice outdoors in the field
during the spring and summer. Plants used for the photographs and
description were the original tree (15 years old) and those
propagated by tie-off layerage and growing on their own roots (six
and seven years old).
Color references herein are made to The Royal Horticultural Society
Colour Chart, 1966 Edition, except where general terms of ordinary
dictionary significance are used. International Union for the
Protection of New Varieties of Plants ("UPOV") descriptors are
described in the Mar. 28, 1979, UPOV Hazelnut guidelines. Botanical
classification: Corylus avellana cultivar `Hunterdon`. Parentage:
Female, or seed, parent is Corylus avellana `Sacajawea`.
`Sacajawea` is the result of a cross of OSU 43.091 (unpatented) x
`Sant Pere` (unpatented). `Sant Pere` is a minor cultivar from
Tarragona (Spain) with very early nut maturity (Tasias-Valls,
1975). OSU 43.091 is reported to be the result of self-pollination
of `Montebello` (unpatented, Italian origin) or pollination by an
unknown cultivar. `Sacajawea` has been reported to express a high
level of tolerance to EFB in Oregon (Mehlenbacher et al., 2008) and
moderate level in New Jersey (Capik and Molnar, 2012). Male, or
pollen, parent is Corylus avellana OSU 616.055 (unpatented,
unreleased seeding). OSU 616.055 is the result of a cross of OSU
309.074 x OSU 280.036. OSU 309.074 (unpatented) is the result of a
cross of `Tonda Gentile delle Langhe` (unpatented, Italian origin)
x OSU 23.017 (unpatented), which is the result of a cross of
`Barcelona` x `Extra Ghiaghli`. OSU 280.036 (unpatented) is a cross
of `Tonda di Giffoni` (unpatented) x `Willamette` (unpatented,
Mehlenbacher et al., 1991), both which are tolerant to EFB.
Incompatibility alleles: `Hunterdon` has incompatibility alleles S1
and S3. The female parent `Sacajawea` has the alleles S1 and S22
and male parent OSU 616.055 has the alleles S3 and S12. `Tonda di
Giffoni` has the alleles S2 and S23, `Tonda Pacifica` (U.S. Plant
Pat. No. 22,715, Mehlenbacher et al., 2011b) and `Wepster` have the
alleles S1 and S2, and `McDonald` has the alleles S2 and S15.
`Hunterdon` has the same S alleles as `Jefferson`. Propagation
(type rooted suckers): Time to initiate roots.--About 30 days at
20.degree. C. Time to produce a rooted young plant.--About six
months at 22.degree. C. Root description.--Fine to thick; freely
branching; creamy white in color. Propagation (type whip grafting):
Time to budbreak on the scions.--About 14 days at 25.degree. C.
Time to produce a grafted plant.--About six months at 25.degree. C.
Plant description: General appearance.--Natural habit is perennial
shrub, but in commercial orchards, is a single trunk tree; upright
plant habit. Growth and branching habit.--Freely branching; about
15 lateral branches develop per plant. Pinching, that is, removal
of the terminal apices, enhances branching with lateral branches
potentially forming at every node. Vigor.--Vigorous growth habit.
Size.--Plant height is about 4.4 meters; plant diameter or spread
is about 2.9 meters. Trunk.--At 30 cm above the soil line; 7.5 cm
(Average of multiple stems) in 2019. Texture is mostly smooth,
glabrous. Trunk color.--199C. Lateral branch description:
Length.--About 37.0 cm; ranges from 32.0 cm to 46.0 cm.
Diameter.--About 6.1 mm; ranges from 5.0 mm to 7.0 mm. Internode
length (at base).--About 1.0 cm. Internode length (at tip).--About
5.5 cm; ranges from 5.0 cm to 6.0 cm. Texture.--Smooth, glabrous.
Strength.--Strong. Color, immature.--144B. Color, mature.--146C.
Color of previous seasons branches.--199C. Foliage description:
Arrangement.--Alternate, simple. Length.--About 13.9 cm; ranges
from 12.0 cm to 16.0 cm. Width.--About 11.2 cm; ranges from 9.9 cm
to 12.4 cm. Shape.--Oblong to ovate. Apex.--Obtuse to acute.
Base.--Cordate. Margin.--Serrate. Texture, upper and lower
surfaces.--Slightly pubescent. Venation pattern.--Pinnate. Color:
Developing foliage.--Upper surface 144B, lower surfaces, 144C.
Fully expanded foliage, upper surface.--Spring and summer, 137A;
late summer and fall, 137A. Fully expanded foliage, lower surface:
spring and summer, 137D; late summer and fall, 137D. Venation,
upper surface: spring and summer, 145A; late summer and fall, 145A.
Venation, lower surface.--Spring and summer, 145A; late summer and
fall, 145A. Leaf bud description: Shape.--Globular. Length: average
7.5 mm. Diameter: average 6.0 mm. Time of leaf budbreak.--Early to
medium, Descriptor-4. `Hunterdon` budbreak is twelve days before
`Jefferson`, concurrent with `Yamhill`, and four days before
`Santiam`. Color.--145B. Petiole description: Length.--About 1.7
cm; ranges from 1.4 cm to 2.0 cm. Diameter.--About 2.8 mm; ranges
from 2.0 mm to 3.0 mm. Texture, upper and lower
surfaces.--Pubescent. Color.--144A. Flower description: Male
inflorescences.--Catkins. Color prior to elongation.--176D. Catkin
length.--Average 32.0 mm. Catkin diameter: average 6.5 mm. Female
inflorescence length at full maturity: average 7.5 mm. Female
inflorescence style color.--47B. Time of female flowering.--Medium,
Descriptor-5. Time of male flowering: Very early, Descriptor-2.
Time of female flowering compared to male flowering.--Protogyny,
Descriptor-1. Involucre constriction.--Absent. Involucre
length.--1.5 times length of nut, Descriptor-7. Size of
indentation.--Strong, Descriptor-7. Strength of serration of
indentation.--Weak, Descriptor-3. Thickness of callus at
base.--Medium, Descriptor-5. Pubescence on husk.--Absent,
Descriptor-1. Density of hairiness of involucre.--Weak,
Descriptor-3. Jointing of bracts.--On both sides, Descriptor-3. Nut
description: Length.--Average 19.7 mm. Width.--Average 19.8 mm.
Depth.--Average 16.8 mm. Nut shape.--Globular, Descriptor-2. Nut
shape index.--(Width+Depth)/2*Length=0.93. Nut compression
index.--(Width/Depth)=1.18. Nut weight.--Average 2.74 g. Kernel
weight.--Average 1.24 g. Kernel percentage (kernel weight/nut
weight).--Average 45.5%. Number of fruits per cluster.--Two to
three. Nutshell coloration.--165B. Number of stripes on
shell.--Many, Descriptor-7. Shape of fruit apex.--Obtuse,
Descriptor-2. Prominence of fruit apex.--Medium prominent,
Descriptor-5. Size of fruit pistil scar on shell.--Very small,
Descriptor-3. Hairiness of top of fruit.--Medium, Descriptor-5.
Curvature of nut basal scar.--Flat, Descriptor-2. Double
kernels.--Absent. Kernel shape.--Globular, Descriptor-2. Shape of
kernel in cross-section.--Circular, Descriptor-2. Lateral groove in
kernel.--Present. Corkiness of pellicle of kernel.--Smooth,
Descriptor-1. Disease/pest resistance.--Plants of `Hunterdon`
exhibit a very high level of tolerance to EFB, referred to as
quantitative resistance or horizontal resistance, caused by the
fungus Anisogramma anomala (Peck) E. Muller. `Hunterdon` has been
evaluated against the strains of the fungus present in New Jersey
(Muehlbauer et al., 2019); a few small cankers may develop under
high disease pressure but many lack stromata equating to reduce
sporulation and subsequent orchard inoculum load. Plants have not
been challenged against all strains of Anisogramma anomala present
in North America and have not been thoroughly evaluated for their
tolerance of bud mites (Phytoptus avellanae Nal.); no bud mites
were observed on the original tree or its propagules grown in East
Brunswick, N.J. Further, no bacterial blight caused by Xanthomonas
campestris pv. corylina was observed on the cultivar during the
course of evaluations. Temperature tolerance.--`Hunterdon` was
selected in East Brunswick, N.J., and is targeted for production in
USDA Plant Hardiness Zones 6a to 7b. Plants of the new Corylus
avellana have been observed to tolerate temperatures from -21 to
38.degree. C.
COMPARATIVE DATA
FIG. 4 presents a phenology chart showing time of female
receptivity, pollen shed, and vegetative budbreak of `Hunterdon`
and other hazelnut cultivars grown in East Brunswick, N.J. over a
time period from January to April of 2018. For each of the
different indicated varieties (`Hunterdon`, Jefferson`, `Yamhill`,
`Santiam`, `Ratoli` and `Gasaway`) upper and lower bar graph
pairings are provided in alignment with their respective varietal
indicators, wherein the upper (top) bar graph of each pairing
represents pistillate (female) flower development as it progresses
over time through each of four stages represented by the
crosshatchings key at the bottom of the chart; and the lower
(bottom) bar graph of each pairing represents staminate (male)
flower development as it progresses over time through each of three
stages represented by different crosshatchings defined by another
key at the bottom of the chart. The different respective stages
correspond to the stages of development as defined and described in
"Flowering phenology of eastern filbert blight-resistant accessions
in New Jersey," Capik, J. M. and T. J. Molnar, HortTechnology
24:196-208, 2014 (hereinafter sometimes "Capik and Molnar (2014)").
Stage 1 of vegetative bud development for each of the varieties is
represented by the solid black rectangles aligned with the varietal
indicators.
FIG. 5 presents a phenology chart showing time of female
receptivity, pollen shed, and vegetative budbreak of `Hunterdon`
and other hazelnut cultivars grown in East Brunswick, N.J., from
December 2018 to April 2019. For each of the different indicated
varieties (`Hunterdon`, Jefferson`, `Yamhill`, `Santiam`, and
`Ratoli`) upper and lower bar graph pairings are provided in
alignment with their respective varietal indicators, wherein the
upper (top) bar graph of each pairing represents pistillate
(female) flower development as it progresses over time through each
of the four Capik and Molnar (2014) stages represented by the
crosshatchings key at the bottom of the chart; and the lower
(bottom) bar graph of each pairing represents staminate (male)
flower development as it progresses over time through each of three
Capik and Molnar (2014) stages represented by crosshatchings
defined by another key at the bottom of the chart. Stage 1 of
vegetative bud development for each of the varieties is represented
by the solid black rectangles aligned with the varietal
indicators.
Disease resistance: `Hunterdon` differs from existing Corylus
avellana cultivars based on its source and type of resistance to
eastern filbert blight (EFB) caused by Anisogramma anomala.
Commercial cultivars previously widely grown in Oregon including
`Barcelona` (unpatented), `Ennis` (unpatented), `Daviana`
(unpatented), `Butler` (unpatented), etc. are highly susceptible to
EFB and cannot be grown in the eastern US without copious
applications of chemical fungicides and heavy pruning to remove
infected stems. Tree death can occur in the eastern US within 5
years of exposure to the systemic fungus.
The more recently developed cultivars `Santiam`, `Yamhill`,
`Jefferson`, `Dorris`, `Wepster`, and `McDonald` and their
associated pollenizers are protected from EFB by a single
resistance gene conferred from Corylus avellana `Gasaway`. This
gene provides a high level of resistance in Oregon and Washington
where the diversity of the fungus is limited (Muehlbauer et al.,
2019), but does not provide a similar level of protection from
disease in the eastern US where the pathogen is endemic and
genetically diverse (Capik and Molnar, 2012; Molnar et al., 2010a,
2010b; Muehlbauer et al., 2018). `Hunterdon` hazelnut is highly
tolerant to EFB but does not carry the single `Gasaway` resistance
allele. It was developed by crossing two unrelated Corylus avellana
plants both exhibiting a high level of tolerance and then selecting
offspring exhibiting enhanced levels of tolerance in the presence
of high disease pressure in East Brunswick, N.J. While `Hunterdon`
plants are not immune to EFB, they have been shown to rarely get
destructive stem cankers that lead to stem die-back and yield
decline.
In a multi-year trial in East Brunswick, N.J., completed in winter
2018 and spanning more than 8 years of exposure to EFB, the average
proportion of diseased wood (total length of EFB-diseased stems per
tree divided by total length of shoot growth) for `Hunterdon` was
2.2% compared to 20.4% for `Yamhill` (unpatented, Mehlenbacher et
al., 2009), 31.2% for `Jefferson` (unpatented, Mehlenbacher et al.,
2011a), and 48.6% for `Gasaway` (unpatented). Previous studies in
New Jersey showed the proportion of diseased wood of `Barcelona` to
be 67.0%, `Tonda di Giffoni` 39%, and `Sacajawea` 21% (Capik and
Molnar, 2012).
Differences were also observed in the number of cankers and average
canker length for `Hunterdon` in comparison to `Yamhill`,
`Jefferson`, and `Gasaway` in the study completed in 2018.
`Hunterdon` exhibited an average of 5.7 cankers per tree with an
average canker length of 14.8 cm. In contrast, `Gasaway` exhibited
an average of 93.0 cankers per tree with an average length of 130.8
cm, `Jefferson` exhibited an average of 36.9 cankers per tree with
an average length of 72.3 cm, and `Yamhill` exhibited an average of
40.5 cankers per tree with an average length of 37.9 cm. As
reported in Capik and Molnar (2012), and as a further point of
comparison in regard to EFB response, `Barcelona` exhibited an
average of 20.4 cankers per tree with an average length of 61.9 cm,
`Tonda di Giffoni` exhibited an average of 39.0 cankers per tree
with an average length of 24.5 cm, and `Sacajawea` exhibited an
average of 7.7 cankers per tree with an average length of 21.5 cm
(Capik and Molnar, 2012). While `Sacajawea`, a cultivar known to be
tolerant to EFB, exhibits relatively similar canker numbers per
tree and just slightly greater average canker lengths to
`Hunterdon`, its proportion of diseased wood is much higher at
21.0% compared to 2.2%.
Nut and kernel characteristics: `Hunterdon` hazelnut is targeted
for the blanched kernel market and specifically for nut production
in the eastern United States in USDA Plant Hardiness Zones 6a to 7b
where most existing cultivars of Corylus avellana cannot be grown
due to the impacts of EFB.
The nut shape is globular and slightly compressed along its depth.
Kernels are mostly globular although some are slightly oblong. The
average single nut weight over the past 6 years for `Hunterdon` is
2.74 g, average single kernel weight is 1.24 g, with an average
kernel to nut ratio of 45.5% (FIG. 3).
`Hunterdon` kernels are smaller than those of `Barcelona`,
`Jefferson`, and `Sacajawea`, and also differ in kernel to nut
ratio. For example, `Barcelona` (as described in Mehlenbacher et
al., 2008), had an average single nut weight of 3.85 grams, average
single kernel weight of 1.66 grams, and an average kernel to nut
ratio of 43.1%. `Sacajawea` (as described in Mehlenbacher et al.,
2008) had an average single nut weight of 2.79 grams, an average
single kernel weight of 1.45 grams, and an average kernel to nut
ratio of 52.1%. `Jefferson` (as described in Mehlenbacher et al.,
2011a) had an average single nut weight of 3.69 grams, an average
single kernel weight of 1.66 grams, and an average kernel to nut
ratio of 42.9%.
`Hunterdon` kernels are slightly larger than `Yamhill` and
`Wepster` and similar to `McDonald` but differ from the three in
several aspects including ratio of kernel to nut and pellicle
removal after roasting. For example, `Yamhill` (as described in
Mehlenbacher et al., 2009), had an average single nut weight of
2.34 grams, an average single kernel weight of 1.13 grams, and an
average kernel to nut ratio of 49.3%. `Wepster` (as described in
Mehlenbacher et al., 2014) had an average single nut weight of 2.39
grams, an average single kernel weight of 1.11 grams, and an
average kernel to nut ratio of 46.6%. `McDonald` (as described in
Mehlenbacher et al., 2016) had an average single nut weight of 2.39
grams, an average single kernel weight of 1.21 grams, with an
average kernel to nut ratio of 50.7%.
Raw kernels of `Hunterdon` have a light brown pellicle with a very
small amount of attached fiber (average rating was 1.3 on a scale
of 1 [no fiber] to 4 [much fiber] with average based on 4 years of
evaluations). Pellicle removal after roasting at 150.degree. C. for
15 min and rubbing is rated on a scale of 1 (complete pellicle
removal) to 7 (no pellicle removal). `Hunterdon` exhibits excellent
pellicle removal, which can be highlighted as one of the traits
that differentiates it from most existing cultivars. Nearly all the
pellicle is removed after roasting with an average rating of 1.0
(averaged from 4 years of evaluations). `Hunterdon` demonstrated
better average pellicle removal than that reported in Oregon for
`Barcelona` (4.2 out of 7.0 as described in Mehlenbacher et al.,
2008), `Jefferson` (3.9 out of 7.0 as described in Mehlenbacher et
al., 2011a), `Yamhill` (4.1 out of 7.0 as described in Mehlenbacher
et al., 2011a), `McDonald` (3.8 out of 7.0 as described in
Mehlenbacher et al., 2016), `Sacajawea` (2.9 out of 7.0 as
described in Mehlenbacher et al., 2011), and `Dorris` (2.4 out of
7.0 as described in Mehlenbacher et al., 2013). It is similar to
`Tonda Pacifica` as described in Mehlenbacher et al. (2011), which
is reported to have a score of 1.5 out of 7.
The average percentage of good kernels (kernels free of defects)
were calculated for `Hunterdon` and found to be 83.8%. There was an
average of 3.8% moldy kernels, 3.0% blank nuts, 2.5% nuts with
shriveled kernels, 1.0% poorly filled, and 5.8% defective kernels
attributed to defects from sucking insect damage, primarily Brown
Marmorated Stink Bug (Halyomorpha halys, Stal, 1855). The
percentage of good kernels for `Hunterdon` was considerably higher
than that reported for `Barcelona` in multiple reports from Oregon
(60.9% good kernels reported in Mehlenbacher et al. [2008] and
69.4% in Mehlenbacher et al. [2013]). The average percentage of
good kernels for `Hunterdon` grown in New Jersey was around the
range reported in Oregon for `Yamhill`, `Jefferson`, `Dorris`, and
`McDonald`. There were few twin kernels observed for `Hunterdon`
(0.25%) and no occurrences of black tips.
Nut maturity date: The nuts of `Hunterdon` are typically borne in
clusters of 2-3 in husks about 50% longer than the nuts. The husks
are flared at the tip (FIG. 2), and open as they dry at maturity.
About 90% of the nuts fall free of the husk at maturity (range
80-100%). The other 10% of the nuts come out of the husks as they
move through the harvester. When mature, the shells are tan to
light brown in color. Harvest date on average is around 10 days
before `Jefferson` when grown in East Brunswick, N.J., typically
around the very last days of August or the first week of
September.
Incompatibility and pollinizers: The trees set a moderate to high
amount of catkins that shed pollen in early mid-season a few days
prior to `Yamhill`. Pollen has been collected and used in several
controlled pollinations, and both quantity and viability appear to
be good. `Hunterdon` has incompatibility alleles S1 and S3 as
determined by fluorescence microscopy. Both alleles are expressed
in the female flowers. S3 is expressed in the pollen because of
dominance. By convention, alleles expressed in the pollen are
underlined.
Time of pollen shed and female receptivity were recorded weekly
from early December 2017 to late March 2019 (FIGS. 4-5). Climatic
conditions vary each year and impact dates of bloom but not usually
the order of progression of bloom among cultivars. Female
inflorescences of `Hunterdon` emerge in early season and are
generally fully receptive around the first week of February in New
Jersey. Pollinizer cultivars that shed compatible pollen in
midseason and late midseason are recommended, with hybrid hazelnut
seedlings (Corylus americana x C. avellana) planted as pollenizers
in eastern and northern regions where cold temperatures and
fluctuating climatic conditions can affect pollen production of C.
avellana. Alternative orchard designs include plantings different
eastern filbert blight resistant cross-compatible cultivars in
adjacent rows to augment pollen production. Flowering times will
continue to be observed and pollinizer recommendations adjusted
accordingly. Pollinizers must be selected that express a high level
of EFB resistance to eliminate/reduce the need for fungicide
control in the entire orchard.
Pests and diseases: Based on field trials under high disease
pressure and greenhouse inoculation trials, both performed in New
Jersey, `Hunterdon` expresses a very high level of tolerance to EFB
(quantitative resistance). Fungicide applications are not expected
to be needed. Small cankers that may develop can be removed through
pruning to reduce inoculum load in production orchards.
Susceptibility to bacterial blight caused by Xanthomonas campestris
pv. corylina has not been quantified, but the original seedling
tree and clonal trees in the replicated trials were not
affected.
Susceptibility to big bud mite (primarily Phytoptus avellanae Nal.)
has not been quantified, but the original tree and trees in the
replicated trials were not affected.
Propagation: Layers of `Hunterdon` are vigorous and root well,
similar to standard cultivars of Corylus avellana.
References:
Capik, J. M. and T. J. Molnar. 2012. Assessment of host (Corylus
sp.) resistance to eastern filbert blight in New Jersey. J. Amer.
Soc. Hort. Sci. 137:157-172.
Capik, J. M. and T. J. Molnar. 2014. Flowering phenology of eastern
filbert blight-resistant accessions in New Jersey. HortTechnology
24:196-208.
Mehlenbacher, S. A., M. M. Thompson, and H. R. Cameron. 1991a.
Occurrence and inheritance of resistance to eastern filbert blight
in `Gasaway` hazelnut. HortScience 26:410-411.
Mehlenbacher, S. A., A. N. Miller, M. M. Thompson, H. B.
Lagerstedt, and D. C. Smith. 1991b. Willamette` hazelnut.
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Mehlenbacher, S. A., A. N. Azarenko, D. C. Smith, and R. McCluskey.
2001. `Clark` hazelnut. HortScience 36:995-996.
Mehlenbacher, S. A., A. N. Azarenko, D. C. Smith, and R. McCluskey.
2007. `Santiam` hazelnut. HortScience 42:715-717.
Mehlenbacher, S. A., D. C. Smith, and R. L. McCluskey. 2008.
`Sacajawea` hazelnut. HortScience 43:255 257.
Mehlenbacher, S. A., D. C. Smith, and R. L. McCluskey. 2009.
`Yamhill` hazelnut. HortScience 44:845-847.
Mehlenbacher, S. A., D. C. Smith, and R. L. McCluskey. 2011a.
`Jefferson` hazelnut. HortScience 46:662-664.
Mehlenbacher, S. A., D. C. Smith, R. L. McCluskey and M. M.
Thompson. 2011b. `Tonda Pacifica` hazelnut. Hort Science
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Mehlenbacher, S. A., D. C. Smith, and R. L. McCluskey. 2013.
`Dorris` hazelnut. HortScience 48:796-799.
Mehlenbacher, S. A., D. C. Smith, and R. L. McCluskey. 2014.
`Wepster` hazelnut. HortScience 49:346-349.
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Molnar, T., J. Capik, S. Zhao, and N. Zhang. 2010b. First report of
eastern filbert blight on Corylus avellana `Gasaway` and `VR 20-11`
caused by Anisogramma anomala in New Jersey. Plant Dis. 94:1265
Muehlbauer, M. F., Tobia J., Honig, J. A., Zhang N., Hillman, B.
I., Morey Gold, K., and Molnar, T. J. 2019. Population
differentiation within Anisogramma anomala in North America.
Phytopathololgy. Published Online: 29 Apr. 2019
https://doi.org/10.1094/PHYTO-06-18-R.
Tasias-Valls, J. 1975. El avellano en la provincial de Tarragona
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Provincial, Tarragona, Spain.
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References