DROUGHT IN PEACH ORCHARDS: SUMMER PRUNING VS. FRUIT THINNING FOR WATER STRESS MITIGATION AND LONG-TERM EFFECTS OF WATER STRESS

When water shortages are imposed late in the season, peach fruit growers could experience problems with attaining commercial fruit sizes.
A water shortage in summer could also have negative effects during the subsequent year.
In this study, irrigation was cut-off until leaf wilting during stage III of fruit development.
Severe summer pruning and heavy fruit thinning were evaluated as techniques for water stress relief and the long-term effects of water stress were evaluated.
Severe summer pruning and heavy fruit thinning improved the water status of the tree (expressed as midday stem water potential), but only fruit thinning produced a benefit in fruit growth.
The results indicated that improvements in water status in response to pruning may be insufficient to promote fruit growth if the pruned trees are unable to provide an adequate supply of assimilates to the developing fruits.
A suitable technique for mitigating the adverse effects of a water deficit on fruit growth should produce a benefit in tree water status and at least maintain certain degree of assimilation capacity.
Fruit thinning, therefore, can be considered as a convenient technique for mitigating the adverse effects of a water stress on fruit growth.
With regards to the long-term effects of water stress, severe water stress during stage III reduced tree reserve concentrations (expressed as root starch concentration in winter) and subsequent fruit set.
Reductions in fruit set may be a negative long-term effect depending on required commercial cropping level.
When low crop loads are required in order to promote fruit quality (fresh market), the reductions in fruit set would not represent a significant problem.

IX International Symposium on Integrating Canopy, Rootstock and Environmental Physiology in Orchard Systems

G. Lopez, J. Girona, J. Marsal

Prunus persica, canopy management, crop load, fruit growth, fruit set, root starch concentration, stem water potential

https://doi.org/10.17660/ActaHortic.2011.903.166