Twilight blackberry variety

Twilight is a thornless, semi-erect, high-quality blackberry, that has very firm, large, dark and sweet fruit berries. It ripens in the early midseason for a semi-erect type of blackberry. Twilight was released by the U.S. Department of Agriculture-Agricultural Research Service breeding program in cooperation with Oregon State University’s Agricultural Experiment Station. 
Twilight produces good yields of very firm fruit with tough skin and an excellent sweet flavor. Twilight berries should be well suited to fresh market production in the early-midseason because it was earlier than Triple Crown variety, had a similar appealing flavor as Triple Crown variety, but was much firmer and with a tougher skin. Over the 3 harvest years, Twilight was lower yielding than Chester Thornless and Triple Crown cultivars. However, in individual years, it was statistically like one or the other. Twilight berries are comparable in weight to Chester Thornless and lighter than those for Triple Crown cultivars. Twilight had an excellent size for clamshell packaging. The number of berries per lateral for Twilight was comparable to Triple Crown and much fewer than for Chester Thornless varieties. Fruit shape can be impacted by drupelet fertility. While Twilight had the highest rating for fertility, it was not statistically different from the other two cultivars. Twilight blackberry has excellent black color that was comparable with Chester Thornless, and while statistically darker than Triple Crown, the color was not meaningfully different from Triple Crown. Twilight has been rated as having comparable firmness and skin toughness to Chester Thornless, and it has rated much better than the softer, more tender-skinned Triple Crown. This combination of firmness, uniformity of shape, medium to large size, and excellent skin toughness make Twilight balckberry an excellent candidate for shipping in clamshells in the wholesale fruit market. When eaten fresh, Twilight berry texture was comparable with Triple Crown and more pleasant than Chester Thornless blackberry. Twilight fruit were harder to pick than the other cultivars in the trial plants. When eaten fresh, Twilight fruit flavor was as good as the highly regarded Triple Crown and better than Chester Thornless. In general, the semi-erect and erect blackberries show more symptoms of heat damage than do the trailing types. While this may be under control of a genetic component, we suspect it is largely due to the earlier ripening of the trailing types when there are fewer high temperature events. All of the semi-erect blackberries compared showed symptoms of heat injury, however the symptoms were much more severe on Chester Thornless, than they were for Twilight or TripleCrown. In California, Twilight held up well and was still sweet and firm after hot (up to 43 C) temperatures. The primocanes of Twilight were slightly less vigorous than those of Chester Thornless and Triple Crown. While differences were noted for floricane vigor, they were not significant; all three of these cultivars grow very well vegetatively. What can not be captured with a score, is how erect growth was in Twilight after cutting the primocanes to 1 m in the summer. The laterals that break grow straight up and typically grow up to 1 m above the trellis. While different management practices were not tried, tipping the primocanes much lower to the ground and having the laterals that break fill the trellised canopy, as opposed to being over it, may increase the area of the fruiting zone and yield. Twilight had shorter and stronger laterals than the two other cultivars. All cultivars showed excellent winter tolerance wherever they were trialed.
As mentioned, Twilight is a thornless, semi-erect blackberry. It has good yields of firm fruit, featuring tough skins and a sweet flavor. The fruit should be well suited to fresh-market production in the early- midseason because it was earlier than Triple Crown. It had a similar appealing flavor to Triple Crown but its skin was firmer and tougher. While Twilight is expected to be adapted to areas where other semi-erect blackberries, such as Chester Thornless, Triple Crown, can be successfully grown, it should be evaluated in colder regions before being widely planted, as one of its grandparents is a winter-sensitive trailing blackberry.