USPP34914P2

USPP34914P2 - Blackberry plant named ‘thunderhead’

Info

Publication number: USPP34914P2
Application number: US17/697,907
Authority: US
Inventors: Michael A. Hardigan; Chad E. Finn
Original assignee: US Department of Agriculture USDA
Current assignee: US Department of Agriculture USDA
Priority date: 2022-03-17
Filing date: 2022-03-17
Publication date: 2023-01-17

Abstract

A new and distinct blackberry cultivar that originated from seed produced from a cross between the thorny primocane-fruiting maternal blackberry plant ORUS 4355-2 and the thornless primocane-fruiting paternal blackberry plant ‘Prime-Ark® Freedom’. ‘Thunderhead’ is the first primocane-fruiting blackberry variety released by the USDA-ARS breeding program in Oregon. This new blackberry cultivar can be distinguished by its exceptionally high plant vigor and yields of medium sized berries with high gloss, firmness, excellent flavor and fruit quality, and relatively small seed size. The berries are well suited for fresh eating, with good sweetness and gloss when picked firm, and low bitter notes. The new and distinct blackberry variety contains a genetic background derived from eastern U.S. germplasm and is expected to grow and is expected to perform well in most areas where primocane-fruiting blackberries are currently grown.

Description

Latin name of the genus and species of the plant claimed: ‘THUNDERHEAD’ is a blackberry plant that is Rubus subg. Rubus Watson.

Variety denomination: The new blackberry plant claimed is of the variety denominated ‘Thunderhead’ Rubus subg. Rubus Watson.

BACKGROUND OF THE NEW PLANT

The present invention relates to a new and distinct blackberry cultivar designated ‘Thunderhead’ and botanically known as Rubus subg. Rubus Watson. This new primocane-fruiting blackberry cultivar was discovered in Corvallis, Oreg. in August 2016, and is the result of a 2014 cross between the maternal blackberry plant ORUS 4355-2 (unpatented) and the paternal blackberry plant ‘APF-153T’ (U.S. Plant Pat. No. 26,990), known as the trade name ‘Prime-Ark® Freedom’. ORUS 4355-2 was a thorny primocane-fruiting selection from a cross of the thorny primocane-fruiting blackberry NC 538 (unpatented) and thorny primocane-fruiting blackberry ‘APF-45’ (U.S. Plant Pat. No. 22,449), known as the trade name Prime-Ark® 45. ‘Prime-Ark® Freedom’ was a thornless primocane-fruiting selection from a cross of the blackberry plant AR 2301 (unpatented) and the thornless primocane-fruiting blackberry plant APF 49T (unpatented). The original seedling of the new cultivar was asexually propagated in Benton County, Oreg. The new cultivar was established in vitro from a cane cutting and microcuttings have been taken and rooted from this sort of culture. The present invention has been found to be stable and reproduce true to type through successive asexual propagations.

SUMMARY OF THE NEW PLANT

The following are the most outstanding and distinguishing characteristics of this new cultivar when grown under normal horticultural practices in Oregon. The new cultivar possesses an erect, primocane-fruiting habit. The cultivar compensates for a lack of complete genetic thornlessness with exceptionally high plant vigor and exceptionally high yields of fruit for a primocane-fruiting type with excellent flavor and quality for the fresh market that is at least on par with than current primocane-fruiting varieties. In Oregon trials, the new cultivar established more quickly in the field than other primocane-fruiting varieties and was able to produce a 2^ndyear baby-crop that yielded higher than full harvest yields in many of the older, more established blackberry trial plots. The new cultivar is mid-season for a primocane-fruiting blackberry grown in Oregon, ripening at a similar time to ‘Prime-Ark® 45’ but with 1.4-to-1.9-fold higher yields over the 2019-2021 growing seasons. In addition to its exceptional plant vigor and yield potential, the new cultivar produces berries with excellent fruit quality that is competitive with current fresh market cultivars. The berries are sweet even when picked firm and show a good combination of firmness and skin toughness without being chewy. Compared to older fresh market blackberries the new cultivar contains fewer bitter notes and smaller, less noticeable seeds. The new cultivar ranked highest for flavor among all primocane-fruiting blackberry samples in the most recent Oregon State University food science survey of stakeholders conducted in 2019. The post-harvest shelf life appears to be on par with other fresh market primocane-fruiting varieties, with berries able to sit for 23 d in cold storage without substantial deterioration or mold growth. No significant disease resistance or susceptibility has been observed in ‘Thunderhead’.

BRIEF DESCRIPTION OF THE PHOTOGRAPHS

This new blackberry plant is illustrated by the accompanying photographs that show the plants, ripening fruit morphology, and harvested fruit; the colors shown are as true as can be reasonably obtained by conventional photographic procedures.

FIG. 1 shows an example of a fruiting cluster with ripe ‘Thunderhead’ fruit.

FIG. 2 shows a close-up example of the size and shape of ‘Thunderhead’ fruit.

FIG. 3 shows a clamshell of ‘Thunderhead’ fruit (left) and ‘Prime-Ark 45’ fruit (right) after 23 days of refrigerated storage at ˜4° C.

FIG. 4 shows a flat of freshly harvested ‘Thunderhead’ fruit.

FIG. 5 shows a 2 year old plot of entire ‘Thunderhead’ plants during flowering in late July.

FIG. 6 shows the morphology of ‘Thunderhead’ flowers.

DETAILED DESCRIPTION OF THE NEW CULTIVAR

The following description of ‘Thunderhead’ is based on observations taken from 2016 to 2021 growing seasons in trials in Corvallis and Aurora, Oreg. This description is in accordance with UPOV terminology. Color designations, color descriptions and other phenotypical descriptions may deviate from the stated values and descriptions depending upon variation in environmental, seasonal, climatic, and cultural conditions. ‘Thunderhead’ has not been observed under all possible environmental conditions. Color terminology follows The Royal Horticultural Society Colour Chart. London (R.H.S.) (5^thedition, 2007).

Table 1 shows plant characteristics of the new cultivar. Characteristics include plant vigor, growth habit, date of bud-break, presence of spines further than 0.6 m from the soil surface, presence of spines less than 0.6 m from the soil surface, weight of primary fruit, uniformity of berry shape, fruit firmness, fruit flavor, fruit soluble solids (%; in Brix), fruit pH, fruit titratable acidity (% as citric acid), and yield (actual kg⋅plt−1). Fruit measurements are from 2020 trial data collected from OSU-NWREC (Aurora, Oreg.).

TABLE 1

Characteristic	Thunderhead	Prime-Ark ® 45

Plant vigor	Very High	High
Growth habit	Erect/Primocane-	Erect/Primocane-
	fruiting	fruiting
Date of budbreak	Week 3,	Week 2,
	March (2021)	March (2021)
Presence of spines further	Low-Moderate	Moderate
than 0.6 m from the soil
surface
Presence of spines less	Moderate	Moderate
than 0.6 m from the soil
surface
Weight of primary fruit	8.2-10.4 g	11.0 g
Uniformity of berry shape	Good	Good
Fruit firmness	Very good	Very good
Fruit flavor	Very good	Good
Fruit gloss	Very good	Good
Texture of fruit when	Very good	Moderate
chewed
Drupelet skin resistance to	Very good	Good
abrasion
Fruit soluble solids (%; in	15.08	15.87
Brix)
Fruit pH	3.52	3.40
Fruit titratable acidity (%	11.00	1.33
as citric acid)
Yield (actual kg · plt-1)	8.32	5.25

Table 2 shows floricane and mature primocane characteristics of the new cultivar. Characteristics include diameter at base, diameter at midpoint, diameter at terminus, internode length at base, internode length at midpoint, internode length at terminus, presence of spines further than 0.6 m from the soil surface, presence of spines less than 0.6 m from the soil surface, floricane color at base, floricane color at midpoint, floricane color at terminus, floricane lateral length, floricane lateral strength, primocane color at base, primocane color at midpoint, primocane color at terminus, and floricane length (range).

	TABLE 2

	Characteristic	Thunderhead

	Diameter at base	1.65 cm
	Diameter at midpoint	1.24 cm
	Diameter at terminus	0.31 cm
	Internode length at base	5.85 cm
	Internode length at midpoint	5.81 cm
	Internode length at terminus	2.37 cm
	Presence of spines further than	Low-Moderate
	0.6 m from the soil surface
	Presence of spines less than 0.6 m	Moderate
	from the soil surface
	Attitude of spine in relation to the	Outwards
	cane
	Floricane color at base	NA (primocane type)
	Floricane color at midpoint	NA (primocane type)
	Floricane color at terminus	NA (primocane type)
	Floricane lateral length	NA (primocane type)
	Floricane lateral strength	NA (primocane type)
	Primocane color at base	RHS 187B
	Primocane color at midpoint	RHS 145A
	Primocane color at terminus	RHA 183A
	Floricane length (range)	NA (primocane type)

Table 3 shows primocane foliage characteristics of the new cultivar. Primocane characteristics include mature compound leaf width, mature compound leaf length, number of leaflets per primocane compound leaf, mature leaflet shape, mature leaflet apex, mature leaflet base, mature terminal leaflet width, mature terminal leaflet length, mature first lateral leaflet width, mature first lateral leaflet length, leaflet margin, leaflet serration teeth length, leaflet serration teeth width at base, spine presence on leaves, pubescence on primocane leaflet: upper surface, pubescence on primocane leaflet: undersurface, primocane leaf color abaxial, primocane leaf color adaxial, petiole length, petiole color: upper surface, petiole color: undersurface, petiolule length: terminal leaflet, petiolule length: first distal leaflet, petiolule color: abaxial, petiolule color: adaxial, stipule length, and stipule width.

	TABLE 3

	Characteristic	Thunderhead

	Mature compound leaf width	15.35 cm
	Mature compound leaf length	16.12 cm
	Number of leaflets per primocane	Usually 3-5
	compound leaf
	Mature leaflet shape	Ovate to round
	Mature leaflet apex	Acuminate abruptly
	Mature leaflet base	Cordate
	Mature terminal leaflet width	5.97 cm
	Mature terminal leaflet length	7.58 cm
	Mature first lateral leaflet width	5.57 cm
	Mature first lateral leaflet length	7.07 cm
	Leaflet margin	Serrate
	Leaflet serration teeth length	0.80 cm
	Leaflet serration teeth width at	0.63 cm
	base
	Spine presence on leaves	Absent or few
	Pubescence on primocane leaflet:	Light/sparse
	upper surface
	Pubescence on primocane leaflet:	Light/even
	undersurface
	Primocane leaf color abaxial	RHS 146B
	Primocane leaf color adaxial	RHA 146A
	Petiole length	7.95 cm
	Petiole color: upper surface	RHS 149A
	Petiole color: undersurface	RHS 185A
	Petiolule length: terminal leaflet	26.30 cm
	Petiolule length: first distal leaflet	19.76 cm
	Petiolule color: abaxial	RHS 60C
	Petiolule color: adaxial	RHS 150B
	Stipule length	1.48 cm
	Stipule width	0.68 cm

Table 4 shows flower and flowering characteristics of the new cultivar. Flower and flowering characteristics include date 1st bloom, date full bloom, date last bloom, petal color, number flowers per cluster, number of petals per flower, flower diameter, petal length, petal width, and number of sepals per flower.

	TABLE 4

	Characteristic	Thunderhead

	Date 1^stbloom	10-July
	Date full bloom	24-July
	Date last bloom	24-August
	Petal color	RHS 155D
	Number flowers per cluster	18.00
	Number of petals per flower	7-10
	Flower diameter	3.68 cm
	Petal length	1.68 cm
	Petal width	1.24 cm
	Number of sepals per flower	5-6
	Peduncle length (cm)	4.68
	Rachis length (cm)	11.47
	Peduncle color	RHS 60B
	Cyme type	Elongate simple cyme

Table 5 shows fruit and fruiting characteristics of the new cultivar. Fruit and fruiting characteristics include date 5% of fruit were ripe, date 50% of fruit were ripe, date 95% of fruit were ripe, weight of primary fruit, weight of secondary fruit, weight of tertiary fruit, diameter of primary fruit at equator, diameter of 2° fruit at equator, diameter of 3° fruit at equator, diameter of 1° fruit at poles: tip, diameter of 1° fruit at poles: base, diameter of 2° fruit at poles: tip, diameter of 2° fruit at poles: base, diameter of 3° fruit at poles: tip, diameter of 3° fruit at poles: base, berry length primary fruit, berry length 2° fruit, berry length 3° fruit, ratio of primary fruit length to width, shape description, uniformity of berry shape, color when full ripe, number of drupelets per fruit, individual seed weight, glossiness, firmness, flavor, texture of fruit when chewed, drupelet skin resistance to abrasion, ease of separation of fruit from pedicel, machine harvestability, resistance to heat damage of fruit, berries per inflorescence—mean, berries per inflorescence range, soluble solids (%; in Brix), pH, titratable acidity (% as citric acid), and yield (actual kg⋅plt−1). Fruit chemistry data is from 2020 field season at OSU-NWREC.

TABLE 5

Characteristic	Thunderhead

Date 5% of fruit were ripe	14-August
Date 50% of fruit were ripe	10-September
Date 95% of fruit were ripe	Fruits until first Fall frost
Fruiting lateral length	20-40 cm
Weight of primary fruit	10.40 g
Weight of secondary fruit	7.27 g
Weight of tertiary fruit	5.95 g
Diameter of primary fruit at equator	2.28 cm
Diameter of 2° fruit at equator	2.05 cm
Diameter of 3° fruit at equator	1.98 cm
Diameter of 1° fruit at poles: tip	1.51 cm
Diameter of 1° fruit at poles: base	2.16 cm
Diameter of 2° fruit at poles: tip	1.30 cm
Diameter of 2° fruit at poles: base	1.87 cm
Diameter of 3° fruit at poles: tip	1.19 cm
Diameter of 3° fruit at poles: base	1.95 cm
Druplets size	Small to medium
Berry length primary fruit	3.48 cm
Berry length 2° fruit	2.94 cm
Berry length 3° fruit	2.71 cm
Ratio of primary fruit length to	1.54
width
Shape description	Blocky to conical
Uniformity of berry shape	Medium
Color when full ripe	RHS 203B
Number of drupelets per fruit	157
Individual seed weight	2.61 mg
Glossiness	Medium to high
Firmness	Very firm
Flavor	Very good
Texture of fruit when chewed	Very good
Drupelet skin resistance to abrasion	Excellent
Ease of separation of fruit from	Very easy
pedicel
Machine harvestability	NA (only picked fresh)
Resistance to heat damage of fruit	Very good
Berries per inflorescence - mean	12
Berries per inflorescence range	8-15
Soluble solids (%; in Brix)	15.08
pH	3.52
Titratable acidity (% as citric acid)	11.00
Yield (actual kg · plt-1)	8.32

COMPARISON WITH PARENTAL AND COMMERCIAL VARIETIES

‘Thunderhead’ differs from the female parent blackberry plant ORUS 4355-2 in that it has a more vigorous plant with significantly greater yields. The fruit are slightly smaller than ORUS 4355-2, but it produces larger numbers with a higher number of fruits per lateral. The ‘Thunderhead’ fruit quality is improved with robust firmness and flavor and appears less susceptible to mold and red berry mite (RBM).

‘Thunderhead’ differs from the male parent blackberry plant ‘Prime-Ark® Freedom’ in that it lacks complete genetic thornlessness, shows higher yields and plant vigor, and produces larger numbers of smaller-sized berries with a more consistent/uniform shape and a smaller, more uniform drupelet size. The ‘Thunderhead’ flavor is less astringent when grown in Oregon.

‘Thunderhead’ differs from the primocane-fruiting blackberry variety ‘Prime-Ark® 45’ in that it has shown higher fruit yields within a similar ripening season/window when grown in Aurora, Oreg. The ‘Thunderhead’ fruit are slightly smaller, with smaller individual drupelet size and somewhat higher drupelet uniformity. The fruit were similarly glossy and sweet to ‘Prime-Ark® 45’, with a similar shelf life and post-harvest appearance after 23 days in refrigerated storage in plastic clam shell packaging at 4° C. The ‘Thunderhead’ fruit contain slightly lower bitter notes than ‘Prime-Ark® 45’, and smaller less noticeable seeds.

Claims

We claim:

1. A new and distinct cultivar of blackberry plant named ‘Thunderhead’, substantially as illustrated and described, characterized by its plant vigor, and exceptional yields of medium sized berries with excellent fresh eating quality, firmness, and flavor, with small seed size.