Originated from a cross of Prime-Ark 45 (APF-45) x A-2286
Plants are slightly thorny
Bushes have erect canes
Fruit weight is 6 g
Berries have a oblong shape
Fruiting habit - primocane-fruiting only
Flowering on floricanes starts in the third week of June
Ripening date (regular) - first week of August
Productivity is 14000 kg from ha
Soluble solids - 11.1%
Cold hardiness is low
Country of origin - United States
Patent US PP27,401 P3 dated November 21, 2016
Current status - cultivated (actual)
Canes that emerge in the spring during the first period of vegetative growth produce flower and fruit without passing through a period of dormancy. The Mary Carmen is a highly precocious cultivar. It initiates fruit production three to four weeks earlier than other primocane blackberry varieties. Bearing type - primocane only.
The canes of the blackberry variety APF-122 are erect and moderately thorny. The variety has less vegetative vigor than other Arkansas cultivars. Its moderate vigor reduces or even eliminates the need for extensive tipping. Canes grow to an average of 1,2 m in length over the course of a single growing season. Primocanes emerge both from the crown of the plant as well as from the suckers.
The time of flowering (50% of plants at first flower) is the middle of June on primocanes. Flowers are white, about 4 cm in diameter.
The blackberry variety Mary Carmen yields medium size fruit, averaging 6 to 9 g. The fruit is round in shape and very firm. The large berries sometimes develop a slightly elongated shape, but the most part are medium size and consistently round. APF-122 produces a heavy primocane crop, reducing the economic viability of floricane production. Yields average 14000 to 16000 kg/ha. When temperatures exceed 30–32 C at the time of flower set, problems with pollination may occur. Time of ripening is the beginning of August on primocanes.
Berries show very little post-harvest color reversion (< 10 %) of the drupelets related to cooling and cold storage. There is little evidence of post-harvest decay or rot when held up to 7 days at 5 °C.
The Mary Carmen blackberry variety provides a late season alternative to contemporary floricane production in cold, continental climates. Growers adjust the harvest window through timely pruning over the course of the season. An effective cane management plan must be developed according to the climatic conditions under which it is being grown. Mary Carmen will be well as addition to autumn raspberry harvest.
The Mary Carmen variety has shown tolerance to powdery mildew (Podosphaera aphanis), anthracnose (Elisinoe veneta), crown gall (Agrobacterium tumefaciens) and botrytis (Botrytis cinerea).