G. Selles’s research while affiliated with Instituto de Investigaciones Agropecuarias and other places
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During the 2008-2009 season, net radiation (Rn) and soil heat flux (G), sensible heat flux (H) and latent heat flux (LE=Λ ETc where ETc is vine evapotranspiration and Λ is the latent heat of vaporization) were measured on a drip-irrigated 'Thompson Seedless' vineyard trained on an overhead trellised system ("parronal español"). The experiment was located in Calle Larga, Aconcagua valley, Chile (32°52'40" S, 70°37'45" O, 795 m a.s.l.). LE and H were obtained from an eddy covariance system. The reference evapotranspiration (ETo) was calculated using the FAO-Penman-Monteith model. Results indicated that the closure (ratio of LE+H to Rn-G) was 0.91 in November '08 and 0.82 in January '09. At flowering (74% solar interception), the mean ratios of LE, H and G to Rn were 0.53, 0.26 and 0.11, respectively. At veraison (98% solar interception) LE, H and G were 0.81, 0.01 and 0.1 of Rn respectively. Also, an increase of crop coefficient (Kc = ETc/ETo) values from October to mid-November was observed. Afterwards, it was almost stable until mid-January when an increase was again observed. A maximum Kc value of 1.3 was reached at veraison.
Soils with unfavourable natural conditions for root development can affect both yield and fruit quality of table grapes, mainly due to an inadequate soil air/water ratio. The objective of this study was to generate information about the adaptation of own-rooted or grafted 'Thompson Seedless' vines grown in soils with different soil air capacity (ACf). The experiment was carried out in pots containing four different soil textural classes (sandy, sandy loam, clay loam and silty loam) that generated different soil air contents (AC). Plants of cultivar 'Thompson Seedless' were grafted on five different rootstocks (110 Richter, Harmony, Ramsey, 1616 Couderc and Freedom), and an own-rooted vine was used as a control. The ACf values ranged between 9-26%, and had a direct relation with oxygen diffusion rates (ODR), which ranged between 0.25 to 0.70 µg cm -2 min -1 . The leaf stomatal conductance was high in soils with AC 22.63%, but not significantly affected by low soil AC. The midday stem water potential (SWPmd) was not affected by AC, and values ranged between -0.55 and -0.63 MPa. AC values higher than 20% decreased the pruning weight of 110-R, Harmony and Freedom, while Ramsey was the less affected in a wide range of AC. Own-rooted plants were significantly affected by low soil air content. In general, in aeration stress condition soils, rootstocks particularly 110-R and Ramsey promote vegetative growth of 'Thompson Seedless' vines, although results need to be confirmed at least one more season.
Avocado trees evolved in Andisoils, which are considered the optimum type of soils for tree growth due to their physical properties; mainly low bulk density (0.5 - 0.8 g cm-3) and high macro porosity (∼ 46%). In Chile, avocado orchards are mostly located in fine textured soils, with bulk densities between 1.3 and 1.5 g cm-3 and macro porosities close to 15%. Due to this fact, there are severe problems of poor root aeration which, in part, are responsible for the low production levels of the crop. The objective of this research was to study the effect of soil aeration in the root zone on avocado water status. The ultimate goal of this study was to generate information for developing irrigation management strategies for avocado orchards that optimize the air and water contents in the soil. The study was conducted during the 2004/05 season. Two-year-old avocado var. 'Hass' on Mexicola root stock were planted in 50 L pots using four soils of different texture. The treatments were TO: loam soil; T1: sandy soil; T2: sandy loam soil; T3: clay loam soil. Soil air content between 5% and 18% affected stomatal conductance, but not stem water potential. Soil air content lower than 17% restricted the oxygen diffusion rate to less than 20 μg cm-2 min-1, the threshold value for normal avocado tree development.
In the Aconcagua Valley, Chile (32° 47′ S, 70° 42′ O), during three consecutive periods, a trial on table grapes cv. Crimson Seedless was carried out. The objective was to evaluate the effect of soil water content and berry phenological stages on trunk diameter variations (TDV), and to determine its possible use in irrigation scheduling. Four treatments were applied: T1, irrigation at 100% crop evapotranspiration (Etc); T 2, 75% Etc; T3, 50% Etc and T4, with a variable irrigation regime between 0 and 100% Etc. Berry phenological stage affected maximum daily trunk growth (MDG) as well as maximum daily trunk shrinkage (MDS). MDG was higher in T1 and depended on soil water content during the phenological stage of berry set to the beginning of veraison, when berry size reached 85% of its final size. Then MDG can be used as a tool for irrigation scheduling. MDS showed a more complex response according to soil water availability, it increased with moderate deficits as well as with soil water excess. Therefore, MDS is not an appropriated indicator for irrigation scheduling in table grapes cv. Crimson Seedless.
This study aimed to evaluate the relationship between water and production in 'Crimson Seedless' table grapes, and to establish threshold values for plants water status. Field experiments were carried out, during a three-year period, in the Aconcagua Valley, Chile, at 32°47'S and 70°42'W, in a clay-loamy textured soil. Different irrigation water amounts were applied, between 40 and 100% crop evapotranspiration (Etc). Stem water potential measured at midday (Ψxmin) and stomatal conductance were closely related to water shortage and yield obtained. Table grape yields decreased in comparison with applied water within the range of studied treatments. Sixty per cent Etc restriction decreased yields in 22%. When plants maintained Ψxmin greater than -0.75 MPa, between berry set and veraison, yield and berry size were high.
During growing seasons 1998/1999, 1999/2001 and 2000/2001 a field trial on irrigated grape vines cv. Chardonnay was carried out. The main objective was the evaluation of the effects of water stress on yield, wine quality, plant water status and nutritional reserves on roots. The following treatments were applied: T1, 100% of water evapotranspiration (Etc) all over the season; T2, 40% of Etc all over the season; T3, no irrigation since bud burst to veraison and irrigation at a 100% of Etc the rest of the season, until harvest; T4, irrigation of 100% of Etc since bud burst to veraison and no irrigation from then on up to harvest. Water shortage significantly decreased shoot growth and berry size. As a result yield reduction was observed. The growing period from bud burst to veraison showed the largest reduction in yield total acidity, global wine quality and phenols measured on the wine did not change with water stress, a different behavior as compared to red wines. Stem water potential (SWP), measured at noon, of plants under no water stress showed a higher SWP of - 0.8 Mpa as compared to those plants under water stress that showed -1.2 Mpa.. Finally, the water deficit induced a reduction of carbohydrate reserves of the root system.
Several physiological indicators of plant water status (stem water potential, SWP , leaf water potential, LWP and trunk growth rate , TGR,), were tested as criteria for irrigation scheduling in table grapes cv Crimson Seedless, growing, in a deep (2 m) clay loamy soil, at the Aconcagua Valley, Chile. Four irrigation treatments were applied: T1, 100% of crop evapotranspiration (Etc), T2, 75% of Etc, T3, 50% of Etc, all over the season, and T4, with a variable amount of water (between 0 to 100% of Etc) all over the season. Stem water potential (SWP) and leaf water potential (LWP) were measured at midday using a pressure chamber. Trunk growth rate (TGR) was measured continuously with an electronic dendrometer. Soil water changes were also measured. The first year results shows that TGR was most sensitive than the other two indicators, however, the interaction between plant pheno-logy and trunk growth must be considered. INTRODUCTION An inadequate water supply at any stage of the productive cycle of table grape limits the production and the quality of the fruit, particularly between flowering and veraison (Peacoock et al., 1998). Therefore, in this period it is important to detect any water deficit, even moderate, as soon as possible, to obtain higher fruit diameter at harvest. Periodic measurements of soil water status are usually conducted for detection of vine water stress (Martín et al., 1990). However, under drip irrigation, a local measure-ment of soil water content is not representative, and many measurements are needed to integrate soil moisture of the wettes zone beneath the dripper (Selles et al., 2003; Myburg, 1996; Or, 1995). Therefore, physiological indicators of plant water status have the potential to be a better water stress indicator (Selles and Berger, 1990; Goldhammer et al., 1999). Leaf Water Potential, LWP, or Stem Water Potential, SWP, (Fereres and Goldhammer, 2003; Schackel et al. 1997; Naor, 2001), measured at midday with a pressure chamber, has been proposed as a standard parameter to determine the plant water status for irrigation scheduling of fruit trees. On the other hand, a continuous recording the variations of trunks diameter was proposed as plant water stress indicator (Selles and Berger, 1990; Myburg, 1996; Michelakis, 1997; Van Louwen et al., 2000; Goldhammer and Fereres, 2001; Moriana and Fereres, 2002). In several fruit species trunk diameter variation has been shown to be sensitive to moisture availability under moderate water stress conditions (Van Louwen et al., 2000; Goldhammer and Fereres, 2001). In addition parameters based on trunk diameter changes were found to be more responsive to moisture soil availability compare with LWP or SWP (Goldhamer et al., 1999). The objective of our project was to evaluate the sensitivity of a few water stress indicators for irrigation scheduling of Crimson Seedless table grapes. The results of the first year are reported here.
The objective of this study was to define the soil available water depletion (SAWD) in avocado, in order to use it as a criterion for irrigation programs in soils of fine texture and low aeration capacity. To determine appropriately the fraction of soil SAWD we performed three independent trials: Trial 1: We evaluated two treatments: T1, irrigation to 100% ETc and then without irrigation for 13 days, until the SAWD reached 60%; and T2: daily irrigation replacing 100% of the evapotranspiration of the crop (ETc). Trial 2: We evaluated three fractions of SAWD before irrigating again: T1:5%; T2:30% and T3:60%. Trial 3: We monitored the SAWD variation in seven orchards of adult avocados. SAWD was monitored using a capacitive probe to determine which percentages of SAWD changed the velocity of water extraction by the trees. Decreases of SAWD up to 60% before irrigating did not affect the plant water status measured as midday stem water potential (MSWP). Also, stomatal conductance (gs) and yield was not affected. According to our results, avocado transpiration is maintained with low soil humidity. This may indicate that avocado has less stomatal regulation compared to other species. It could be related to the environmental conditions in which these species evolved. This characteristic of avocados, which may sometimes be a limiting factor, may provide an advantage in irrigation management in soils with low air capacity, since it will allow decreasing soil water content without producing stomatal closure, thus improving the oxygen flow in this type of soil.
... Decreasing fruit firmness was described by several authors, when vines were treated with increasing water limitation and drought stress levels [12,18]. However, Zunñiga et al. [9,30] did not find decreasing fruit firmness when screening the response of quality and yield parameters of 'Flame Seedless' and 'Thompson Seedless' to different irrigation amounts. Overall, firmness is known to be highly dependent on the maturity stage of the berries, turgor pressure, water content [31], epidermal deterioration, and increasing cell wall elasticity [32]. ...
... Our study found oleic acid at 5.79 ± 0.10 % and linoleic acid at 5.37 ± 0.02 %, which is consistent with the lower amounts (7-10 %) reported in previous findings. The concentration of fatty acids in avocado oil varies significantly depending on the extraction methods (Liu et al., 2023) and the maturity of the fruit (Ferreyra et al., 2016), highlighting the need for standardization in fatty acid analysis. This variability may explain the differences between our results and those of other studies. ...
... The syringes were reconnected to the Rhizons; 4 h later the solution was extracted, acidified, and the soluble Cu concentration was determined. For 55 d, Rhizon samples were collected daily, with applications of 250 mL of water to replace the sample volume removed (maximum 180 mL d À1 ) and the humidity lost to evapotranspiration (47 to 66 mL d À1 in Quillota, Ferreyra et al., 2009). ...
... La concentración de calcio en la fruta tiende a aumentar rápidamente durante la etapa principal de división celular, la absorción de calcio y distribución en la planta es de particular importancia en el manejo de la fruta en postcosecha. Los exportadores utilizan la concentración de calcio en el fruto como una herramienta de determinación de la calidad (Rodríguez, 2012). Se encuentra una relación lineal entre el contenido de calcio en fruto y su peso. ...
... and cluster weight (g). Similar reduction in yield and its components of grapevines were reported by Ferreyra et al. [31], where deficit water and low soil water content cause stomata to close, limiting the plant's ability to take up carbon dioxide (CO 2 ) for photosynthesis, which in turn causes water stress [32]. Furthermore, Farooq et al. [33] found that dry matter production, assimilate translocation, and dry matter portioning all went down. ...
... In pears, the fruit diameter growth was closely correlated temporally with trunk shrinkage (Maas, 2007). In contrast, daily grape berry shrinkage and recovery occurred much later (hours) compared to trunk shrinkage, with berry recovery times varying with fruit growth stage according to the relative water supply to the berry from xylem and phloem (Otarola et al., 2014). While fruit growth is often measured at harvest to determine the impacts of different irrigation schedules, such dynamic fruit growth measurements are rarely utilised by researchers. ...
... Second, previous studies found that soil organic carbon (SOC), soil total nitrogen (TN), soil available nitrogen (AN), soil available phosphorus (AP), soil water content (SM) and soil pH had significant influences on bacterial communities during secondary forest succession (Jiang et al. 2021;Wang et al. 2019;Xu et al. 2021b). In addition, Liu et al. (2015) found that soil texture changed significantly during secondary forest succession; the variations in soil texture have significant influences on plant properties, root exudate composition (Vieira et al. 2020), soil oxygen content (Ferreyra et al. 2008) and soil water (Li et al. 2014), thereby further affecting soil bacterial diversity and community composition (Karimi et al. 2018;Xia et al. 2020). However, the effects of soil texture on the soil bacterial community structure during secondary forest succession have often been overlooked (Jiang et al. 2021;Liu et al. 2020;Qiang et al. 2021;Xu et al. 2021b). ...
... Such methods should have a lower negative effect on growth and development of the grape vine canopy than shading of vines. The capacity of evaporating water to lower surface temperature is well understood, particularly in relation to transpirational cooling of leaves through the high latent of vaporisation (Selles et al. 2011; Villagra et al. 2011). This raises the possibility of using evaporating water to cool whole vines. ...
... These modifications affect underground or above-ground parts: reduction of Leaf Area (LA) and rolling up of leaves (Slama et al., 2005). Vegetative development is very disturbed under conditions of water starvation (Ferryra et al., 2004). Several studies reported significant depressive effect of water stress on the number of leaves per plant and leaf area (Nwagbara et al., 2021, Molaaldoila et al., 2016, Samson and Helmut 2007, and AbdouRazakou et al., 2013. ...
... In 2011/2012, SWP decreased below −1 MPa, showing a moderate water stress in T1. Selles et al. [31] also showed that vegetative growth is affected by the amount of water applied in Crimson Seedless cultivar growing in the Aconcagua Valley. That study also reported that water applied affected not only pruning weight but also trunk growth. ...
