Articles
Regulated deficit irrigation induces reversible physiological stress without compromising vegetative growth in defruited ‘ANABP 01’ apple trees
Article number
1468_12
Pages
81 – 88
Language
English
Abstract
Frequent drought and rising irrigation costs in Australia’s Goulburn Valley region threaten apple production, highlighting the need for effective water-saving strategies.
This study evaluated the eco-physiological and vegetative responses of defruited ‘ANABP 01’ (Bravo™) apple trees grafted on M.9-T337 to sustained and regulated deficit irrigation at the Tatura SmartFarm, Victoria, during the 2025-26 season.
Trees were assigned to one of three irrigation treatments: full irrigation at 100% crop evapotranspiration (ETc; control, CTRL), sustained deficit irrigation (SDI; 53% ETc applied throughout the season), and regulated deficit irrigation (RDI; 53% ETc applied for 45 days between 46 and 91 days after full bloom). Relative to CTRL SDI induced chronic water stress, increasing canopy temperature by 1.4°C, reducing midday stem water potential and stomatal conductance by up to 46 and 48%, respectively, and decreasing cumulative shoot growth by 20%. In contrast, RDI imposed acute but transient stress during the deficit period, with stem water potential and stomatal conductance reductions exceeding 50%. Upon restoration of full irrigation, physiological parameters recovered rapidly to levels comparable to CTRL. Final shoot length was not significantly affected by RDI (p>0.05). These results indicate that, in the absence of fruit sink competition, post-cell division RDI induces reversible physiological stress without compromising seasonal vegetative development.
Evaluation is required to determine potential effects on subsequent season’s yield and fruit quality prior to commercial implementation.
This study evaluated the eco-physiological and vegetative responses of defruited ‘ANABP 01’ (Bravo™) apple trees grafted on M.9-T337 to sustained and regulated deficit irrigation at the Tatura SmartFarm, Victoria, during the 2025-26 season.
Trees were assigned to one of three irrigation treatments: full irrigation at 100% crop evapotranspiration (ETc; control, CTRL), sustained deficit irrigation (SDI; 53% ETc applied throughout the season), and regulated deficit irrigation (RDI; 53% ETc applied for 45 days between 46 and 91 days after full bloom). Relative to CTRL SDI induced chronic water stress, increasing canopy temperature by 1.4°C, reducing midday stem water potential and stomatal conductance by up to 46 and 48%, respectively, and decreasing cumulative shoot growth by 20%. In contrast, RDI imposed acute but transient stress during the deficit period, with stem water potential and stomatal conductance reductions exceeding 50%. Upon restoration of full irrigation, physiological parameters recovered rapidly to levels comparable to CTRL. Final shoot length was not significantly affected by RDI (p>0.05). These results indicate that, in the absence of fruit sink competition, post-cell division RDI induces reversible physiological stress without compromising seasonal vegetative development.
Evaluation is required to determine potential effects on subsequent season’s yield and fruit quality prior to commercial implementation.
Authors
E.G. Bekele, M. Peavey, N. Valluri, I. Goodwin, A. Scalisi
Keywords
canopy temperature, crop evapotranspiration, shoot growth, stomatal conductance, water use efficiency
Groups involved
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