Articles
Managing water stress to maximize ‘Gala’ apple fruit size using micro-tensiometers
Article number
1409_37
Pages
281 – 290
Language
English
Abstract
We conducted an experiment using field grown ‘Gala’ apple trees at Geneva, NY in 2022. The first objective of the study was to develop a relationship of apple fruit growth rate and stem water potential at various times in the growing season.
The second objective was to define a stem water potential threshold with micro-tensiometer sensors (MT; FloraPulse sensors) to determine when to irrigate field grown apple trees.
During the 2022 growing season three different water regimes were compared (fully irrigated, rain only and rain exclusion with no irrigation to induce water stress). We continuously measured stem water potential using MT embedded in the trunks of trees.
We also measured fruit diameter each week and related fruit growth rate to stem water potential.
Our results suggest stem water potential was effectively measured in apple trees with the MT. Trees subjected to rain exclusion showed lower stem water potentials (greater stress) compared to fully irrigated trees.
However, fully irrigated trees did not show differences compared to trees receiving only rain, except in dry periods.
The fully irrigated trees had the highest fruit growth rate (mm diameter increase per day) which declined over the course of the season.
The rain exclusion trees (no irrigation) had lower fruit growth rate throughout the season and lower final fruit weight when compared to fully irrigated and rain only trees.
The rain exclusion trees had less fruit red color at harvest.
This study was our first attempt to relate apple fruit growth dynamics to continuous measurements of water stress for maximizing fruit size and crop value in apple orchards.
The second objective was to define a stem water potential threshold with micro-tensiometer sensors (MT; FloraPulse sensors) to determine when to irrigate field grown apple trees.
During the 2022 growing season three different water regimes were compared (fully irrigated, rain only and rain exclusion with no irrigation to induce water stress). We continuously measured stem water potential using MT embedded in the trunks of trees.
We also measured fruit diameter each week and related fruit growth rate to stem water potential.
Our results suggest stem water potential was effectively measured in apple trees with the MT. Trees subjected to rain exclusion showed lower stem water potentials (greater stress) compared to fully irrigated trees.
However, fully irrigated trees did not show differences compared to trees receiving only rain, except in dry periods.
The fully irrigated trees had the highest fruit growth rate (mm diameter increase per day) which declined over the course of the season.
The rain exclusion trees (no irrigation) had lower fruit growth rate throughout the season and lower final fruit weight when compared to fully irrigated and rain only trees.
The rain exclusion trees had less fruit red color at harvest.
This study was our first attempt to relate apple fruit growth dynamics to continuous measurements of water stress for maximizing fruit size and crop value in apple orchards.
Authors
L. González Nieto, A. Huber, R. Gao, L. Cheng, A.D. Stroock, A.N. Lakso, T.L. Robinson
Keywords
Malus × domestica, stem water potential, water management, FloraPulse sensors, fruit size, fruit growth rate, fruit red color
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