Rubus subgenus Rubus Watson
The new primocane-fruiting cultivar of blackberry called ‘APF-153T’ is described herein. The new cultivar originated from a hand-pollinated cross of Ark. Selection A-2301T (unpatented selection)×APF-49T (unpatented selection) made in 2004. The seeds resulting from this controlled hybridization were germinated in a greenhouse in the spring of 2005 and planted in a field near Clarksville, Ark. (West-Central Arkansas). The seedlings fruited in the summer of 2007 and one seedling, designated APF-153T, was selected for its very large attractive fruit, very good flavor, excellent plant health, very early ripening, thornlessness, erect canes and primocane fruiting habit in 2007.
The new and distinct cultivar of blackberry originated from a hand-pollinated cross of Ark. Selection A-2301T (non-patented, unreleased genotype; female)×APF-49T (non-patented, unreleased genotype; male) made in 2004 and located near Clarksville, Ark. (West-Central Arkansas). The botanical designation of the new cultivar of blackberry is Rubus subgenus Rubus Watson. The seeds resulting from this controlled hybridization were germinated in a greenhouse in the winter to early spring of 2005 and planted in a field near Clarksville, Ark. The seedlings fruited in the summer of 2007 on floricanes and one seedling, designated APF-153T, was selected for its very large fruit with, attractive fruit appearance, very good flavor, excellent plant health, very early ripening, thornless canes, and cane erectness. Its primocane-fruiting habit was confirmed later that summer by observing primocane flowers.
During 2007, the original plant selection was propagated asexually from root cuttings at the above-noted location, and a test row of 30 plants was established. Subsequently, a larger test planting has been established with asexually multiplied plants at the same location in Arkansas. Additionally, the cultivar has been tested at test plots in Watsonville, Calif., and at this location propagation was from root cuttings from the Clarksville, Ark. test plot plants.
The new cultivar has been asexually multiplied annually since 2005 by the use of root cuttings and by rooting adventitious shoots from root cuttings. It forms new shoots from adventitious buds on root cuttings readily. During all asexual multiplication, the characteristics of the original plant have been maintained and no aberrant phenotypes have appeared.
Its primocane fruiting performance is substantially better in more moderate summer climates such as Watsonville, Calif., as evidenced by larger fruit weight and higher yields compared to Clarksville, Ark. The cultivar differs from most blackberry cultivars which are floricane fruiting.
The accompanying photographs show typical specimens of the new variety in color as nearly true as it is reasonably possible to make in a color illustration of this character.
Plants and fruit of this new cultivar differ phenotypically from its parents. The new cultivar fruits on primocanes, has larger fruit, and ripens earlier than parent A-2301T, and fruit is larger and has increased levels of primocane fruiting than parent APF-49T. Although blackberries (Rubus subgenus Rubus Watson) are highly heterogeneous and outcrossing, and most clones contain genes from more than one species, the new cultivar and its progenitor lines phenotypically exhibit characters predominately of the erect eastern United States species, Rubus allegheniensis Porter (highbush blackberry).
Plants of the new cultivar are vigorous and prolific and row establishment following planting is rapid. Both primocanes and floricanes are erect in growth habit. The canes can be trained to a self-supporting hedgerow although it is beneficial to use a trellis with supporting wires to prevent canes from falling over due to wind or heavy fruit loads. The plants are thornless. Plants and fruit are moderately resistant to anthracnose [Elsinoe veneta (Burkh.) Jenkins], and plants appear immune to orange rust [Gymnoconia nitens (Schwein.) F. Kern and H. W. Thurston.]. No screening has been done for resistance to double blossom/rosette [Cercosporella rubi (Wint.) Plakidas]
The floricane bloom period of the new cultivar begins on 10 April, compared to 17 April for ‘APF-45’ (U.S. Plant Pat. No. 22,449) and is shorter in length compared to ‘APF-45’. Primocane bloom period begins 15 June compared to 30 June for ‘APF-45’.
Floricane fruit of the new cultivar begins ripening 28 May, 9 days earlier than ‘APF-45’, but has a shorter fruiting period of about 25-30 days compared to ‘APF 45’ of 40 days. Primocane first ripe fruit date was 18-20 of July on tipped primocanes and ripened earlier than ‘APF-45’ of 8 Aug. At Watsonville, Calif. first ripe was 10-15 Aug. with harvest extending into early October, compared to ‘APF-45’ which had first ripe date of 20 Aug.
Fruit yields of the new cultivar on floricanes are usually 1.4 kg/plant (3.1 lb) if the floricanes are retained for fruiting, compared to 1.8 kg/plant (4.0 lb) for ‘APF-45’ in West-Central Arkansas. Fruit yields of the cultivar on primocanes in West-Central Arkansas average 0.6 kg (1.5 lb/plant) compared to 0.8 kg (1.8 lb/plant) for ‘APF-45’ but in Watsonville, Calif. achieves 4-5.5 kg/plant (8.8 to 12.1 lb).
The fruit is elongated to blocky in shape, bright glossy black in color, and very attractive. The floricane fruit is large (9-13 g). Primocane fruit in West-Central Arkansas of the new cultivar averaged 8.8 g/berry while ‘APF-45’ averaged 5.8 g/berry but in Watsonville, Calif. ranged from 13-16 g/berry. Storage (shipping) potential of fresh fruit of the new cultivar is not as good compared to that of ‘APF-45’.
The fresh fruit rates very good in flavor, comparable to ‘APF-45’ and ‘Natchez’ (U.S. Plant Pat. No. 20,891), but not as high as for ‘Ouachita’ (U.S. Plant Pat. No. 17,162) and higher than ‘APF-12’ (U.S. Plant Pat. No. 16,989). The flavor is sweet and mildly acidic, with a distinct blackberry aroma. The soluble solids concentration averages 9.7 to 10.5% on shiny black fruit harvested from floricanes but can extend to 13.2% for primocane fruit. Floricane fruit and flower clusters are medium-large, cymose, and are mostly borne on the periphery of the plant canopy, providing easy access to harvest. Flower fertility is high and clusters are well filled.
Primocane fruit and flowers are borne on the cane terminus or on lateral branches if primocanes are tipped, and fruiting continues down the primocane during the season. Canes usually attain a length of 4.5 to 5.0 ft prior to the appearance of flower buds. The number of nodes down the cane that develop flowers is largely dependent on the length and conditions of the late summer to fall growing period.
The following is a detailed description of the botanical and pomological characteristics of the subject blackberry. Color data are presented in Royal Horticultural Society Colour Chart designations (1986 2nd edition). Where dimensions, sizes, colors, and other characteristics are given, it is to be understood that such characteristics are approximations of averages set forth as accurately as practicable.
Plants used for botanical data were three years old and grown on a fine sandy loam soil with trickle irrigation near Clarksville, Ark. The plants were fertilized near budbreak (late March on average) with complete or nitrogen fertilizer, and had an additional nitrogen fertilizer application in early July. Primocanes were tipped at approximately 45 inches, and grown in a hedgerow training system. Weeds were controlled with pre- and post-emergence herbicides supplemented with mechanical weed control activities. A single application of liquid lime sulfur was applied to the plants at budbreak, but no other fungicides were used. The descriptions reported herein are from specimens grown near Clarksville, Ark. unless otherwise noted.