Prime-Ark Horizon blackberry variety

A new blackberry variety APF-268 has been released by the University of Arkansas System Division of Agriculture, named Prime-Ark Horizon. This is primocane fruiting, thorny variety, introduced as complement to Prime-Ark 45 for commercial production for primocane fruit. Prime-Ark Horizon has reduced thorns compared to Prime-Ark 45. Prime-Ark Horizon demonstrated high floricane crop potential. Primocane berries are large, with larger fruit size potential than other primocane-fruiting varieties in summer heat and potential primocane crop extension beyond the Prime-Ark 45 season.
Berries are very firm in storage, and otherwise comparable to Prime-Ark 45 in postharvest potential. Floricane first harvest is a few days later than Prime-Ark 45 and near that of Ouachita (second week of June). Floricane harvest period averaged 40 days. Primocane first harvest averaged the beginning of August, just before Prime-Ark 45. Primocane fruiting can potentially extend until mid-October, providing a fruiting period of over 60 days. Prime-Ark Horizon’s berry weight averaged 8 g overall for floricanes. Berries were often up to 10 g for floricanes.
The primocane berries averaged 7 g. The floricane and primocane average weights are much closer than other primocane-fruiting varieties, suggesting more berry weight stability in summer heat during primocane flowering and fruiting. Berry shape was noted to vary with Prime-Ark Horizon, and in some years curved berries were observed in most test locations.
Primocane double berries were not seen, as is common with Prime-Ark 45 in Arkansas due to heat effects. This further suggests some heat tolerance for Prime-Ark Horizon. However, temperatures above 32 С were observed to occasionally result in primocane flower death with Prime-Ark Horizon, so full heat tolerance is not implied.
Floricane yields have exceeded 5500 kg/ha in research plots usually in the year after planting. Floricane yield is influenced by the degree of primocane fruiting the prior year. More primocane fruit production often equates to lower floricane yields the following season. Crop control with pruning is strongly advised to balance crop, particularly in the first year of floricane fruiting if no primocane crop is produced in the planting year.
Primocane yields ranged from 550 to 1650 kg/ha, depending on year and environment. Flavor has consistently been rated good with light aromatics. As with most blackberry varieties, Prime-Ark Horizon can have variation in sweetness. Berries were noted at times to be tart, particularly when very high floricane crop was experienced. Storage for 7 days has been comparable to Prime-Ark 45, it has also shown potential for longer-term storage particularly in the retention of firmness. In addition to excellent firmness in storage, leakage and decay have been among the best measured in the Arkansas program.
Prime-Ark Horizon (APF-268) plants have shown good health, except when excessive floricane yields were experienced that resulted in reduced floricane leaf size as well as upward leaf curling. No orange rust nor anthracnose were observed on Prime-Ark Horizon.
Winter hardiness has been comparable to Ouachita, and has shown very limited winter injury to a low of minus 13 С. Spring freeze damage has not been observed.