Rubus plants are rather unusual among fruit crops in that they have a perennial root system but have biennial canes. The two cane types are primocanes, or first-year canes, which are usually vegetative, and floricanes, which are the same canes and produce fruit in the next growing season. In red raspberry (Rubus ideaus L.), primocane- and floricane-fruiting cultivars have substantial commercial value. In blackberry (Rubus subgenus Rubus Watson), floricane-fruiting has been the basis of all blackberry production and commercial primocane-fruiting cultivars did not exist before the release of ‘Prime-Jim’® and ‘Prime-Jan’® by the University of Arkansas in 2004 (Clark et al., 2005). However, there is much to be done to improve primocane-fruiting blackberries. In my discussion, I highlight potential value of primocane-fruiting blackberries, provide background on the origin of this type of fruiting habit, and comment on breeding challenges that have been identified in their early improvement.
Clark, J.R., Moore, J.N., Lopez-Medina, J., Perkins-Veazie, P. & Finn, C.E. 2005 Prime January (APF-8) and Prime-Jim (APF-12) primocane-fruiting blackberries HortScience 40 852 855
Lim, Y.K. & Knight, V.H. 2000 The successful transfer of primocane fruiting expression from raspberry to Rubus hybrid berry Euphytica 116 257 263
Lopez-Medina, J., Moore, J.N. & McNew, R.W. 2000 A proposed model for inheritance of primocane fruiting in tetraploid erect blackberry J. Amer. Soc. Hort. Sci. 125 217 221
Stanton, M.A., Scheerens, J.C., Funt, R.C. & Clark, J.R. 2007 Floral competence of primocane-fruiting blackberries Prime-Jan® and Prime-Jim® blackberries grown at three temperature regimes HortScience 42 508 513
Strik, B., Clark, J.R., Buller, G. & Finn, C. 2008 Management of primocane-fruiting blackberry to maximize yield and extend the fruiting season Acta Hort. 777 423 428
USDA, ARS, National Genetic Resources Program 2006 Germplasm Resources Information Network (GRIN) [online database] National Germplasm Resources Laboratory Beltsville, MD 30 Oct. 2006 <http://www.ars-grin.gov/cgi-bin/npgs/acc/display.pl?1448923>.