Black raspberry plant named ‘Shekinah Tahi’

Latin name of genus and species:

Variety denomination: ‘Shekinah Tahi’.

The present invention relates to a new and distinct cultivar of spineless black raspberry,. The new cultivar is distinguished from other black raspberry cultivars by being completely spineless in every part of the plant. Fruit is produced on floricanes giving mid-season production. ‘Shekinah Tahi’ fruit are too hard to pick for machine harvest, process production. ‘Shekinah Tahi’ fruit are too tightly bunched and not firm enough for fresh market commercial sales. ‘Shekinah Tahi’ offers significant opportunities for home gardeners as an easy to manage spineless variety. Traditional spiny black raspberries require considerable input for management and in the home garden ‘Shekinah Tahi’ will provide a welcome alternative.

Black raspberries are well known for forming few or no suckers from their roots and new canes come from the basal crown of the plant. Traditional black raspberries are very spiny and they display a rambling growth because canes are arching and spreading, unlike the more upright growth of red raspberries. The spreading growth of black raspberries makes them difficult to manage, especially in a home garden situation. Traditional management practices to contain the plants involve cane tipping to reduce height, making the plants bushy, branching and low growing. When cane tips of the arching canes of black raspberries touch the ground, they form roots, especially in the Fall. A new plant is formed at each point where a cane tip produces roots, making them difficult to confine to one spot within a garden. A management practice of tipping black raspberries at about 1 m tall (around 3 feet) has been developed to limit tip-rooting and to promote significant branching and increased production of the new primocanes.

Hybrids between the black raspberry,and the red raspberry,, are well known and are known as purple raspberries for their fruit color. Purple raspberries (L.) frequently do not tip root or produce suckers. In breeding of new black or red raspberry varieties, it is desirable to access traits from the other species. However, in practice it is difficult to breed traits from one species into the other and it takes multiple generations of breeding.

In red raspberries, the trait of fruit firmness was introgressed from the old black raspberry cultivar ‘Cumberland’. Dark color was the major obstacle to overcome to get back to acceptable red raspberry color.

When attempting to move traits from red raspberry into black raspberry there have also been challenges to get back to a true black color. When moving traits from red raspberry into black raspberries retention of purple fruit color is the obstacle. Incorporating the primocane fruiting trait into black raspberries took three generations, ending with backcrossing to black raspberry to produce ‘Ohio's Treasure’ (U.S. Plant Pat. No. 27,871 P3). This process was alleviated by the dominant inheritance of the primocane fruiting trait.

The introduction of the gene for spinelessness from red raspberry into black raspberry was made significantly more difficult because its inheritance is recessive. For expression of this trait, it is necessary to incorporate two copies of the spineless gene into the diploid plant. To get a spineless black raspberry spineless selections were crossed with black raspberry. Selections from these hybrids were then inbred to expose the trait by back-crossing, selfing, or sib crossing to see the expression of the trait. ‘Shekinah Tahi’ results from around an eight-generation sequence of crosses, selfing and back crossing to black raspberry. The process began with crosses between ‘Munger’ black raspberry and the spineless red raspberry selections ‘SCRI 689/81’ and ‘SCRI 6921/21’ in 1969 and 1970. ‘SCRI 689/81’ and ‘SCRI 6921/21’ themselves were 4 and 5 generations of breeding from the old red raspberry cultivar ‘Burnetholm’, the source of the genetically spineless trait. Hence ‘Shekinah Tahi’ is 12-13 generations away from ‘Burnetholm’. ‘Shekinah Tahi’ was selected in 2010, over a period of 40 years since the original black raspberry cross in Scotland and as much as 65 years since the selection of ‘AR1’, a spineless selection derived from selfing ‘Burnetholm’. ‘Burnetholm’ was reported to carry genetic spinelessness by D. Lewis in 1939 and the trait was linked with eglandular cotyledons, where glandular hairs were absent on the cotyledonary leaves of spineless plants (). ‘AR1’, the spiny selections ‘3A/69’ and ‘3B/45’ and their spineless derivatives ‘S25/8’, ‘S29/97’ and ‘S29/122’ were produced in the 1950s. A range of spineless red raspberry cultivars has been developed in Scotland, England and around the world.

Named varieties of black raspberry have been cultivated since the 1800's, firstly with selections collected from the wild and then later from open pollinated seedlings and deliberate crosses. Almost 200 clones were mentioned in Hedrick's “The Small Fruits of New York” in 1925, with the majority of them being collected from the wild or from chance seedlings. Around twenty varieties resulted from deliberately grown seedling populations, and only six were the result of a deliberate crosses, the majority being from open pollinated seed lots. From all the selections mentioned in Hedrick's book in 1925, only three have been retained to the present day, ‘Cumberland’, ‘Munger’ and ‘Plum Farmer’, all from the 1890s, with ‘Munger’ being still the cultivar of choice for machine harvest, process production in Oregon. The genetic diversity of black raspberryL. described in 1925 included black, yellow, orange and white fruited types, with or without bloom on the fruits and canes, and it also included two spineless varieties, Davison (1859) and Fay (1874). No record exists of these two varieties being used for breeding and it is assumed that the varieties have been lost.

Until the advent of more recent collections and their study the black raspberry was believed to have limited genetic diversity. However, limited genetic diversity was shown to be solely amongst the present range of cultivars and there was found considerable diversity amongst wild black raspberries. (Michael Dossett, Nahala Bassil, Kim Lewers and Chad Finn 2012: Genetic Diversity in wild and cultivated black raspberry (L.) evaluated by simple sequence repeat markers—Genetic Resources and Crop Evolution 59. 10.1007/s10722-012-9808-8.). In the absence of the diversity as found in wild collections, and as represented in The Small Fruits of New York in 1925, the spineless trait and the floricane fruiting traits have been introgressed from red raspberry into the black raspberry through the work initiated by Derek Jennings in Scotland and carried out by Harry Swartz in Maryland respectively. In red raspberries the tendency in recent years has been to develop dual cropping varieties that bear a crop on the tips of the new primocanes and another crop on the floricanes in the following spring and summer. Economically this has become important as there are two production periods on the same variety and a spread of the marketing of the fruit. In black raspberry the production of cultivars bearing a primocane crop and a floricane crop has also been a desirable breeding objective and the primocane trait was sought from red raspberries, leading to the development and release of ‘Ohio's Treasure’ U.S. Plant Pat. No. 27,871 P3, a variety with small (1-2.6 g), rather soft fruit. The primocane fruiting habit also has been developed from purely black raspberry genetics, with crosses between selections of wild types, leading to the release of the two black raspberry cultivars ‘Explorer’ and ‘Niwot’. ‘Explorer’ has since been discarded due to the lack of self-fertility and ‘Niwot’ is being recognised for its primocane and floricane production. ‘Jewel’ has large fruit for a variety solely derived fromL. black raspberry. The origin of ‘Jewel’ is reported to be ‘Dundee x’ (Bristol x Dundee) in the 1973 release notice. However, in “Genetic Diversity in wild and cultivated black raspberry (L.) evaluated by simple sequence repeat markers” this origin is questioned, and the derivation is suggested to be from ‘Huron’ or ‘Rachel’, and ‘Dundee’. Plants of ‘Jewel’ are vigorous, erect, winter hardy, consistently productive and canes are very spiny, typical of black raspberries. Fruiting is mid-season and fruit of ‘Jewel’ are firm, glossy and flavorful. ‘Jewel’ appears to be more disease resistant than most other black raspberries and it has slight susceptibility to powdery mildew and resistance to anthracnose. Fruit of ‘Jewel’ have a moderately tight cluster at the tip of fruiting laterals, and it exhibits concentrated ripening and a short production period. Sun scald of the plant and fruit may be a problem during hot weather conditions.

The present invention relates to a new and distinct cultivated variety (cultivar) of black raspberry, unique because of its genetically stable, completely spineless canes. The new cultivar is distinguished from other black raspberry cultivars by its completely spineless canes and black fruit. This is unlike the usual purple raspberries, from the hybrid origin, of a black-red raspberry cross. ‘Shekinah Tahi’ fruits on long, totally spineless, floricane laterals having tight clusters of fruit at lateral tips and some individual or paired fruits at the lateral leaf nodes, resulting in a moderately long season crop of large attractive black fruit. ‘Shekinah Tahi’ fruit have moderate firmness, making them unsuitable for shipping or for a long shelf life in the commercial market chain. However, they will last well for a home gardener or a U-Pick operation. Fruit release from the receptacle with moderate retention strength, making ‘Shekinah Tahi’ unsuitable for machine harvest-process production, with best quality fruit only being picked by hand harvest. ‘Shekinah Tahi’ produces a high yield of large fruit, and combined with the spineless canes makes the variety highly suited for the home garden producer. The spineless, vigorous, and semi-upright canes of ‘Shekinah Tahi’ also have a reduced ability to tip root, producing less spawn of new plants than either traditional spiny black raspberries, or from the suckers which are usual with red raspberries. ‘Shekinah Tahi’ pruning and training may be handled in a similar way to red raspberry, with no need to tip prune, making it possible for tall canes to be grown on a trellis and tipped when dormant during winter.

The new cultivar of black raspberry arose from the original importation to New Zealand of open pollinated seed from Dundee, Scotland of a selection named ‘SCRI 8232C9’ which was from the cross of the two spiny selections ‘SCRI 7861D13’ x ‘SCRI 7860D8’. ‘SCRI 7861D13’ was from the cross ‘Munger’ x ‘SCRI 7562B10’, a first backcross to black raspberry. The spineless selection ‘SCRI 7562B10’ came from the cross of ‘SCRI 7251/31’ (‘Munger’ x ‘SCRI 6921/21’) x ‘SCRI 7346/3’ (‘Munger’ x ‘SCRI 689/81’). ‘SCRI 7860D8’ was from the cross ‘Munger’ x ‘SCRI 7560C11’, another first backcross to black raspberry. The spineless selection ‘SCRI 7560C11’ came from the cross of ‘SCRI 7251/56’ (‘Munger’ x ‘SCRI 6921/21’) x ‘7346/3’ (‘Munger’ x ‘SCRI 689/81’). In New Zealand two selections were chosen from the open pollinated seedlings produced from ‘SCRI 8232C9’, ‘V23’ and ‘V32’. Each of these selections was crossed with ‘Jewel’ black raspberry to produce a further generation of breeding improvement, the populations ‘88407’ and ‘88407R’ from intercrossing ‘Jewel’ and ‘V23’ and the populations ‘88408’ and ‘88408R’ from intercrossing ‘Jewel’ and ‘V32’ yielding 4 and 7 selections respectively, one of which was released as the variety ‘Ebony’ in New Zealand, with purple fruit. In the following generation 8 selections were intercrossed, giving a further 11 selections. In 1995 seedlings from crosses between red raspberries were grown on the Hall family farm at Woodstock, New Zealand, and amongst them was a spineless black raspberry with black fruit of unknown origin which was designated ‘Woodstock Black’.

‘Shekinah Tahi’ is a species hybrid with mostly black raspberry,L. background, but with added traits from red raspberryL. including genetic spinelessness, the recessive gene s designating spine-free growth, improved uprightness and increased fruit size. The process by which these traits have been moved into the black raspberry is known as introgression which was begun by crossing the black raspberry seed parent ‘Munger’ with the spineless red raspberry pollen parents ‘SCRI 6921/21’ and ‘SCRI 689/81’. In the first generation of seedlings all plants were spiny due to the dominant effect of the spiny genes from the black raspberry ‘Munger’. In the second generation of breeding crosses between selections from the first generation gave seedlings which segregated for expression of spinelessness (ss) and spininess (genotypes Ss and SS) as designated by D Lewis in 1939 in his paper “Genetical studies in cultivated raspberries, I: inheritance and linkage” published in Journal of Genetics Vol. 38 Pages 367-379. Dominant spininess was represented by a capital S and the recessive spineless trait was represented by the lower case s, which needed to be present in a homozygous condition (ss) for the character to be expressed. Thus, the process continued with backcrosses to the black raspberries ‘Munger’ (SS) and ‘Jewel’ (SS), giving spiny seedlings in the first generation, followed by an inbreeding generation to allow the spineless trait (ss) to be expressed.

Spineless blackberries have genetic spinelessness through an analogous gene derived from the diploid (2×) blackberry species,var(lacking thorns or spines). In breeding fromvartetraploid (4×) blackberries were produced by crossing with a spiny tetraploid wild type, and this was inbred to produce a spineless variety known as ‘Merton Thornless’. ‘Merton Thornless’ was crossed with USA tetraploid blackberries to produce the varieties ‘Smoothstem’ and ‘Thornfree’, and ‘Thornfree’ formed the basis for breeding all the spineless varieties from the Arkansas breeding program and other programs around the world. With tetraploids the inheritance of the homozygous gene s (ssss) in breeding has different segregation ratios from diploid (2×) black and red raspberries, making it even more difficult to select transgressive segregants bearing the trait advancements desired for breeding improvement.

In each generation of breeding a predominating effect was occurring known as “linkage drag”, where, due to the small-tight chromosomes “crossing over” events were limited and genuine change was hard to achieve. However, these changes are needed to shift spinelessness into a plant bearing black raspberry fruit but expressing the spineless trait. In the case of transferring the primocane fruiting trait from red raspberry into the black raspberry ‘Ohio's Treasure’ the process was simplified by the dominant inheritance of that trait, and a primocane fruiting essentially black raspberry cultivar was achieved within three generations of breeding. However, in the development of ‘Shekinah Tahi’ what was sought was for the recessive gene conferring the spineless trait to be transferred from its position on a red raspberry chromosome into the analogous position in the black raspberry genome. This process was held back at each generation of crossing, inbreeding and backcrossing by a range of other traits being carried forward from the red raspberry background. The introgression process was further complicated due to the necessity of the crossing over event needing to happen in both chromosomes bearing the spiny and spineless gene loci, so that undesirable traits from red raspberry would be left behind.

In the case of ‘Shekinah Tahi’, the introgression of the spineless trait into black raspberry was held back (linkage drag) by the purple color of the fruit typical of black raspberry x red raspberry hybrids being carried from one generation to the next. The breakthrough in getting a spineless derivative with black fruit was achieved by the selection of the chance seedling that was designated ‘Woodstock Black’, having both spineless growth and the desirable black fruit color.

In the process of introgression of black fruit color back into black raspberries linkage drag worked in favour of the variety development process through carrying some desirable traits along with the purple fruit color which was eventually lost. These have included improved fruit size and an improved cane growth uprightness into the new hybrid black raspberries.

‘Shekinah Tahi’ is the result of open pollination of an unnamed breeding seedling (not patented). The unnamed breeding seedling (i.e., female parent) originated from a cross between ‘Woodstock Black’ (not patented) and ‘Jewel’ (not patented). Bulk seedlings derived from the cross of ‘Woodstock Black’ (not patented) and ‘Jewel’ (not patented), including the female parent, were grown in 2009. After open pollination with the unnamed breeding seedling, the selection ‘RZ10022’ was chosen in 2010 for its very large black fruit, spineless canes and semi-upright growth habit. This selection ‘RZ10022’ has been multiplied vegetatively in New Zealand and assessed for its production and qualities and has been designated ‘Shekinah Tahi’.

‘Shekinah Tahi’ has been asexually propagated by tissue culture in Auckland, New Zealand and grown on in a commercial nursery in Nelson, New Zealand for assessment trials from 2010. No aberrant plants have been observed through all this asexual propagation and all plants have displayed similar spineless canes, growth and fruiting capabilities. Plants established in tissue culture without difficulty and multiplication in culture has been easy to achieve.

The following is a description of the new variety using color terminology in accordance with The Royal Horticultural Society Color Charts (R.H.S.C.C.) 2015 edition.

The following is a detailed description of ‘Shekinah Tahi’ based on outdoor performance in Nelson province, New Zealand, and tunnel house performance in the Waikato and Bay of Plenty (other provinces in New Zealand). These observations have been extended and detailed by performance in Whately, Massachusetts where USA trials have been carried out. Observations and measurements have been made on plant morphology, fruit production and on post-harvest performance.

The following characteristics distinguish ‘Shekinah Tahi’ from other black raspberries:

When compared to similar known variety ‘Munger’, ‘Shekinah Tahi’ has a larger average fruit weight (4 grams compared to 2.5 grams) and is spine free, compared to ‘Munger’, which has spines present on the canes.