scholarly journals Deficit Irrigation to Control Vegetative Growth in Apple and Monitoring Fruit Growth to Schedule Irrigation

HortScience ◽  
1995 ◽  
Vol 30 (6) ◽  
pp. 1229-1232 ◽  
Author(s):  
Robert C. Ebel ◽  
Edward L. Proebsting ◽  
Robert G. Evans

A standard fruit growth curve, used commercially as an aid to hand thinning, was compared to periodic volume measurements of apple fruit (Malus domestica Borkh. `Delicious') subjected to early season regulated deficit irrigation (RDI) to determine when to end RDI, which is used to control vegetative growth and save water. RDI suppressed stem water potential, stomatal conductance, and fruit growth rate compared to the trickle- and furrow-irrigated controls, which wetted about one-half and the entire soil volume, respectively. Full irrigation was restored to RDI trees by trickle and microsprinklers, which wetted about one-half and the entire soil volume, respectively, after terminal buds set. Stem water potential, stomatal conductance, and fruit growth rate of RDI trees increased to that of the controls, except for RDI/trickle trees, which had 80% the stomatal conductance of the other treatments. Fruit weight at harvest was affected by an interaction of irrigation treatment and cropload. RDI trees had similar or less vegetative growth and similar or higher yield efficiency than the controls. We recommend ending RDI before fruit growth declines below the standard curve.

2007 ◽  
Vol 58 (11) ◽  
pp. 1068 ◽  
Author(s):  
Mark G. O'Connell ◽  
Ian Goodwin

Partial rootzone drying (PRD) is a new irrigation strategy whereby water is withheld from part of the rootzone while another part is well watered. A successful PRD strategy should reduce tree water use through stomatal control of transpiration and reduce vegetative growth while maintaining fruit size and yield. A field experiment examined crop water relations and production performance of PRD in a commercial apple orchard on loam soil in the Goulburn Valley, Australia. The orchard consisted of high-density (1420 trees/ha) 8-year-old ‘Pink Lady’ apple trees trained as central leader and irrigated by microjets. The effects of PRD on leaf/stem water potential, vegetative growth, yield components and fruit quality were investigated during two seasons (2001–02, Year 1 and 2002–03, Year 2). The 2-year average growing season reference crop evapotranspiration and rainfall was 954 and 168 mm, respectively. Three irrigation treatments were established: (1) deficit irrigation (DI, supplied 50% of water to a fixed side of tree); (2) PRD supplied 50% of water to alternating sides of tree; (3) and conventional irrigation (CI, supplied 100% water to both sides of tree). Irrigation inputs under the CI treatment were 334 and 529 mm for Year 1 and Year 2, respectively. In Year 1, the volume of irrigation applied to CI treatment inputs equated to the replacement of predicted crop evapotranspiration (ETc) based on a mid-season FAO-56 crop coefficient with adjustment for tree size. Vegetative growth, fruit production and water status showed both PRD and DI treatments led to a classical ‘deficit irrigation’ water stress response. Leaf water potential, leaf conductance, fruit size, shoot growth and yield were reduced on PRD and DI trees compared to the fully watered (CI) trees. In Year 2, CI inputs exceeded estimated ETc by 2-fold. Consequently, minimal or no differences between irrigation regimes were measured in stem water potential, vegetative growth, yield components and fruit quality. Fruit disorders (sunburn, russet, misshape, markings, frost damage) were not affected by irrigation regime in either season. We contend that further effort is required to determine under what circumstances or environments there is a PRD response that saves water and maintains yield and quality for apple.


2008 ◽  
Vol 59 (3) ◽  
pp. 270 ◽  
Author(s):  
María Gómez-del-Campo ◽  
A. Leal ◽  
C. Pezuela

In 2005, four irrigation treatments were applied to a 3-year-old cv. Cornicabra orchard. In T1, wetted soil volume was maintained close to field capacity by irrigating when soil sensors indicated that soil water potential in the root zone had fallen to –0.03 MPa and 0.06 MPa from spring until 15 August and from 15 August until September, respectively. On those days, 8, 6, 4, and 2 h of irrigation was applied to T1, T2, T3, and T4, so that over the season they received 106, 81, 76 and 31 mm of irrigation, respectively. The high value for T3 was the result of a valve failure on 13 June. Measurements were maintained throughout the experimental period of relative extractable water (REW) to 1 m depth at the wetted volume (0.30 m from a drip emitter), shoot length, trunk diameter, stem water potential (Ψstem) and leaf conductance (gl). The irrigation treatment significantly affected REW (P < 0.10), Ψstem, gl and vegetative growth (P < 0.05). Ψstem, and trunk diameter were the least variable parameters and Ψstem and shoot growth were the most sensitive to water stress. Although T1 received 24% more water than T2, no significant differences were detected in vegetative growth. T2 should be considered the optimum irrigation value. The mean monthly Kc for T2 was 0.086. The failure of the valve in T3 simulated a wet spring followed by limited irrigation. Irrigation applied was similar to T2 but shoot growth stopped one month earlier and lower values of Ψstem and gl were observed after mid August. REW was highly related to vegetative growth, 66% of maximum being achieved at REW 0.53 and 50% at 0.45. gl was independant of plant or soil water status and did not determine vegetative growth. A strong relationship established Ψstem as a good indicator of vegetative growth and hence of water stress. Shoot growth was 66% of maximum at Ψstem –1.5 MPa and 50% at –1.8 MPa.


1997 ◽  
Vol 7 (1) ◽  
pp. 23-29 ◽  
Author(s):  
Kenneth A. Shackel ◽  
H. Ahmadi ◽  
W. Biasi ◽  
R. Buchner ◽  
D. Goldhamer ◽  
...  

To be useful for indicating plant water needs, any measure of plant stress should be closely related to some of the known short- and medium-term plant stress responses, such as stomatal closure and reduced rates of expansive growth. Midday stem water potential has proven to be a useful index of stress in a number of fruit tree species. Day-to-day fluctuations in stem water potential under well-irrigated conditions are well correlated with midday vapor-pressure deficit, and, hence, a nonstressed baseline can be predicted. Measuring stem water potential helped explain the results of a 3-year deficit irrigation study in mature prunes, which showed that deficit irrigation could have either positive or negative impacts on tree productivity, depending on soil conditions. Mild to moderate water stress was economically beneficial. In almond, stem water potential was closely related to overall tree growth as measured by increases in trunk cross-sectional area. In cherry, stem water potential was correlated with leaf stomatal conductance and rates of shoot growth, with shoot growth essentially stopping once stem water potential dropped to between −1.5 to −1.7 MPa. In pear, fruit size and other fruit quality attributes (soluble solids, color) were all closely associated with stem water potential. In many of these field studies, systematic tree-to-tree differences in water status were large enough to obscure irrigation treatment effects. Hence, in the absence of a plant-based measure of water stress, it may be difficult to determine whether the lack of an irrigation treatment effect indicates the lack of a physiological response to plant water status, or rather is due to treatment ineffectiveness in influencing plant water status. These data indicate that stem water potential can be used to quantify stress reliably and guide irrigation decisions on a site-specific basis.


HortScience ◽  
2011 ◽  
Vol 46 (2) ◽  
pp. 173-177 ◽  
Author(s):  
Ken Shackel

Field experiments have been performed on grapevine as well as a number of woody tree species (almond, prune, pear, cherry) to determine the relation of plant water potential to a number of indices of plant physiological activity (leaf conductance, vegetative growth, and fruit growth and composition). Horticultural benefits of regulated deficit irrigation (RDI) have been documented in several crops (grapevine, almond, prune, cherries), but management of irrigation to achieve these benefits is difficult without a reliable plant-based measure of stress. Midday stem water potential (SWP) has proven to be a robust, reliable, and practical measure of stress and closely related to physiological responses at the leaf and whole plant level [stomatal conductance (gS), vegetative growth, and fruit growth and composition such as soluble solids and fruit color].


1995 ◽  
Vol 120 (4) ◽  
pp. 577-582 ◽  
Author(s):  
Amos Naor ◽  
Isaac Klein ◽  
Israel Doron

The sensitivity of leaf (ψleaf) and stem (ψstem) water potential and stomatal conductance (gs) to soil moisture availability in apple (Malus domestics Borkh.) trees and their correlation with yield components were studied in a field experiment. Two drip irrigation treatments, 440 mm (H) and 210 mm (L), were applied to a `Golden Delicious' apple orchard during cell enlargement stage (55-173 days after full bloom). Data collected included ψstem, y leaf, gs, and soil water potential at 25 (ψsoil-25) and 50 cm (ψsoil-50). No differences in midday ψleaf's were found between irrigation treatments. Stem water potential was higher in the H treatment than in the L treatment in diurnal measurements, and at midday throughout the season. Stomatal conductance of the H treatment was higher than the L treatment throughout the day. Stomatal conductance between 0930 and 1530 hr were highly correlated with ψstem. The H treatment increased the percentage of fruit >65 mm, and increased the proportion of earlier harvested fruit reaching marketable size compared to the L treatment. Fruit size in the first harvest and the total yield were highly correlated with ψstem. The degree of correlation between plant water stress indicators and yield component decreased in the following order: ψstem>ψsoil-25,>ψsoil-50>ψleaf. The data suggest that midday ψstem may serve as a preferable plant water stress indicator with respect to fruit size.


2016 ◽  
Vol 34 (2) ◽  
pp. 161-173 ◽  
Author(s):  
José Manuel Mirás-Avalos ◽  
Francisco Pérez-Sarmiento ◽  
Rosalía Alcobendas ◽  
Juan José Alarcón ◽  
Oussama Mounzer ◽  
...  

2021 ◽  
Author(s):  
Erica Casagrande Biasuz ◽  
Lee Kalcsits

Dwarfing rootstocks are used to control tree vigor allowing for increased densities that increase apple production. Although there is considerable variation among rootstocks in dwarfing capacity, the mechanisms by which rootstocks affect vigor in apple scions remains unclear. Here, Honeycrisp apple growth and water relations were compared among three rootstocks; M-9 as the industry standard and two less studied Geneva series rootstocks; G.87 and G. 814 in Washington, USA. Trees were acquired from a commercial nursery and planted in 2017. In 2018 and 2019, scion physiological, isotopic and morphological traits were measured to better understand the link between rootstock-driven vigor and physiological traits. Rootstock affected scion shoot growth (P <0.001), stomatal conductance (P< 0.01) and stem water potential (P <0.001). Rootstocks with low vegetative vigor like M.9 also had lower stomatal conductance and enriched leaf δ13C and δ18O isotope composition. Plant growth was positively correlated with stomatal conductance and stem water potential. Rootstocks also affected plant water status and net gas exchange. Here, we report an association between rootstock-induced vigor and scion physiological traits such as gas exchange, stem water potential, and leaf carbon and oxygen isotope composition. This research has implications for the understanding of the mechanisms of dwarfing by rootstocks in apple.


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