DO PRIMOCANES AND FLORICANES COMPETE FOR SOIL WATER IN BLACKBERRY?

A study was done to determine the hydraulic relationship between primocanes and floricanes in ‘Marion’ trailing blackberry and to identify any water limitations to plant and fruit development during alternate-year (biennial) production.
Irrigation was applied weekly by drip and scheduled as needed to replace 100% of the estimated crop evapotranspiration (ET) requirements.
On any given day, primocane water potential, measured using a pressure chamber, was nearly identical between ‘on-year’ (floricanes and primocanes present) and ‘off-year’ (only primocanes present) plants.
Floricane water potential, on the other hand, was consistently lower (by 0.3–0.6 MPa) than primocane water potential throughout the fruiting season, especially during midsummer when crop water demands was high.
Water potential was significantly correlated to evaporative water demands (expressed as reference ET) in both cane types, and when normalized to atmospheric conditions, remained nearly constant between irrigations.
Such constant water potentials indicate that plant water status was not limited by soil water availability and hence would probably not benefit from extra or more frequent irrigation.
However, based on different water potentials between cane types, it appears that primocanes and floricanes are hydraulically independent and therefore may compete for water in dry soil conditions.

IX International Rubus and Ribes Symposium

D.R. Bryla, B.C. Strik

Rubus spp. hyb, alternate-year production, crop evapotranspiration, irrigation, plant water potential

https://doi.org/10.17660/ActaHortic.2008.777.73