IRRIGATION STRATEGIES TO MINIMIZE DROUGHT-INDUCED YIELD REDUCTION IN 'FORELLE' PEAR TREES
Water resources in the Western Cape, South Africa, are limited and water restrictions inevitable during years of drought. Because global warming-induced climatological changes may further limit water resources, the potential for main-taining optimum fruit yield and quality by means of deficit irrigation was investigated in the Warm Bokkeveld production region. Forelle pear trees on BP3 rootstock were subjected to 15 irrigation treatments which consisted of combinations of 50%, 70% or 90% plant available water (PAW) depletion or no irrigation during four phenological phases, that is vegetative growth and cell division, cell enlargement, fruit ripening and postharvest. The response of the trees was evaluated over three seasons (2008/09, 2009/10 and 2010/11) to develop guidelines for optimal irrigation management. Rainfall plus irrigation had a marginal effect on vegetative growth. Trees irrigated at 90% PAW depletion during Phases 2 or 3 or throughout the season, and trees that received no irrigation during Phase 3, had earlier leaf fall, out of season bud break and bloom. Limiting irrigation especially during ripening or throughout the foregoing season decreased the flower index and flowers per bunch in the following season. Water deficits, particularly in Phases 2 and 3 or throughout the season, reduced yield through its effects on fruit growth, final fruit size and fruit numbers. Limited irrigation during the vegetative growth and fruit cell division phase or post-harvest, which did not decrease yield significantly, seems to have potential to save water. Deficits in Phases 2 and 3 enhanced fruit maturation in all seasons.
Volschenk, T. (2014). IRRIGATION STRATEGIES TO MINIMIZE DROUGHT-INDUCED YIELD REDUCTION IN 'FORELLE' PEAR TREES. Acta Hortic. 1038, 155-162
Pyrus × communis, deficit irrigation, bloom, shoot growth, fruit size, quality