Relationship between fruit weight and the fruit-to-leaf area ratio, at the spur and whole-tree level, for three sweet cherry varieties

Fruit weight is the main quality parameter of sweet cherries and leaf area/fruit is the most important characteristic influencing fruit weight. The objective of this study was to determine the relationship between Mean Fruit Weight (MFW) and the Fruit Number to Leaf Area Ratio (FNLAR) for `Bing¿, `Van¿ and `Lapins¿, grown under tatura-trellis and vase training systems, at both the spur and whole-tree level. The research was performed through regression analysis with FNLAR as the independent variable and MFW as the dependent variable. There were no significant interactions between training system and cultivar for the effect of FNLAR on MFW at either the spur or whole-tree level. Also, there were no significant differences between training systems. The R2 for the relationships per cultivar were higher at the whole-tree level than at the spur level. At both levels, `Lapins¿ had the highest fruit weight potential and `Van¿ the lowest. At the spur level, the slopes of the regression were similar for the different cultivars, but at the whole-tree level, `Van¿ was less sensitive. The better fit at the whole-tree level suggests that fruits of a spur are supplied not only by the leaves on that spur, but also from other less fruit-loaded spurs, from non-fruiting shoots and from reserve

Fruit dry weight and quality of 'bing' sweet cherries grown without source limitations

Understanding the seasonal pattern of potential fruit growth is important for identification and timing of possible management operations, and quantification of this pattern is an important prerequisite to serve as input for crop growth models. `Bing¿ sweet cherry trees were heavily thinned at 63 degree-days (DD) (=8 days) after full bloom so weight and quality of the remaining fruit could be monitored under conditions of limiting and non-limiting carbohydrate supply. The effect of fruit thinning on mean shoot growth and trunk cross-sectional area also was analysed to detect possible translocation from reproductive to vegetative growth. Mean Fruit Dry Weight (MFDW) of tagged fruit was estimated weekly, based on fruit diameter, to identify the moment of the onset of competition between fruit within trees. At harvest, Fruit Number to Leaf Area Ratio (FNLAR, fruits m-2 LA) was 52% lower in heavily-thinned trees than in non-thinned trees. Yield per tree was higher (

Effect of fruit-to-leaf area ratio on fruit quality and vegetative growth of 'bing' sweet cherry trees at optimal leaf area index

Fruit yield and quality determine grower income from commercial sweet cherry orchards. The objective of this study was to determine the effect of Fruit Number to Leaf Area Ratio (FNLAR, fruit m-2 LA) on Mean Fruit Weight (MFW), firmness (F), soluble solids content (SSC), titratable acidity (TA) and SSC:TA ratio of `Bing¿ sweet cherries trees of near-optimal leaf area index (LAI). The effect of FNLAR on Mean Shoot Growth (MSG) and trunk cross-sectional area increment (TCSAI) also was analysed to determine possible competition between reproductive and vegetative growth. Regression analysis was used with FNLAR as the independent variable. While SSC:TA, MSG and TCSAI were not significantly correlated to FNLAR (P>0.05), MFW, TA and SSC decreased linearly with increasing FNLAR (

Estimation of Leaf area in sweet cherry using a non-destructive method

Leaf area measurement can be a time consuming process and requires sophisticated electronic instruments. The objective of this research was to develop a simple, accurate, non-destructive and time saving predictive model for leaf area (LA) estimation in sweet cherry trees. Linear regression equations were fitted and evaluated for three cultivars and two training systems using alternatively the length (L), the width (W) and their product (L*W) as independent variables. Regression using L*W variable fitted the data better (R2 = 0.994) than L or W (R2 = 0.863 and 0.787, respectively). The slopes using L*W as the explanatory variable were between 0.6776 and 0.6442 for different combinations of cultivar and training system. Combinations of cultivar training system showed different slopes (P<0.05), except for «tatura-Bing» and «vase-Lapins». A general equation had a slope of 0.6612 with R2 = 0.993 (slightly lower than considering all combinations of cultivar and training system). Validation of the general equation using extra data from a «Lapins/ Mahaleb» orchard showed high accuracy (R2 = 0.9826), but underestimated LA. However, the general equation can be used for predicting LA for practical purposes, such as estimating Leaf Area Index of commercial orchards

Uso de fotos hemiesféricas para la elaboración de modelos de altura de la regeneración en Nothofagus pumilio

Martínez Pastur, G.; Lencinas, M.V.; Soler Esteban, R. CADIC-CONICET. Casilla 92 (9410) Ushuaia, Argentina. [email protected]. Cellini, J.M.; Barrera, M. Universidad Nacional de La Plata, La Plata. Argentina. Peri, P. UNPA-INTA-CONICET, Río Gallegos, Argentina.El crecimiento en altura de la regeneración es la principal variable empleada para caracterizar la continuidad de bosques primarios y manejados. Entre los condicionantes bióticos y abióticos, la cobertura del dosel determina la cantidad de luz disponible. Se desarrollaron modelos de predicción de altura de regeneración de Nothofagus pumilio en relación con parámetros de cobertura y radiación obtenidos mediante fotos hemiesféricas, para bosques primarios y manejados. Se emplearon 3700 pares de datos (edad-altura) obtenidos durante 2002-2007 en parcelas permanentes de muestreo (n=16), caracterizadas con fotos hemiesféricas empleando un lente Sigma 8mm y analizadas usando el programa Gap Light Analyzer v.2.0. Se ajustaron modelos (Altura=a.Edadb.(c+d.X+e.X²)) por medio de técnicas de regresión no-linear que utilizaron como variables independientes a la altura y la edad de las plántulas, y como variables dependientes a la cobertura de copas (CC), el índice de área foliar efectivo (IAF), la radiación global (RG) y el porcentaje de radiación global incidente (PRG). Los modelos ajustados tuvieron un ajuste aceptable (r²=61%-63%) generando curvas polimórficas donde H aumentó hasta un máximo (20-25 cm en plántulas de 6 en CC 55%, LAI 1.0, GR 12.0 W.m² o PGR 50%) para luego decrecer en todas las edades analizadas con mayores o menores valores de dichas variables. Los bosques primarios presentaron CC=89.5%, LAI=2.6, GR=3.5 W.m² y PGR=14.3%, mientras que la corta de protección presentó CC=56.5%, LAI=0.8, GR=14.1 W.m² and PGR= 57.2%. El desarrollo de estos modelos es una herramienta útil para diseñar nuevas estrategias de manejo forestal al predecir la respuesta de la regeneración.Estudio financiado por el proyecto PAE2004 22428 (SECYT-Argentina), y gracias a la colaboración de la Consultora “Servicios Forestales” y el Aserradero Los Castores (Tierra del Fuego - Argentina)

Sweet cherry production in South Patagonia

In South Patagonia, the total sweet cherry (Prunus avium L.) area has increased from 176 ha in 1997 to 507 ha in 2004, of which 232 ha are located in Los Antiguos (46°19¿ SL; 220 m elevation), 158 ha in the Lower Valley of Chubut River (LVCHR) (43°16¿ SL; 30 m elevation), 52 ha in Sarmiento (45°35¿ SL; 270 m elevation), 35 ha in Esquel (42°55¿ SL; 570 m elevation) and 30 ha in Comodoro Rivadavia (45°52¿ SL; 50 m elevation). The most common varieties are `Lapins¿, `Bing¿, `Newstar¿, `Sweetheart¿, `Stella¿, `Sunburst¿ and `Van¿ grafted on `Mahaleb¿, `Pontaleb¿, `SL 64¿, `Colt¿ or `Mazzard¿ rootstocks. Trees generally are drip-irrigated and planted at high densities, using training systems such as Tatura, central leader and modified vase (2700, 1100 and 1000 trees ha-1, respectively). Growers in Los Antiguos are more traditional, planting mainly as vase (400 to 1000 trees ha-1) or freestanding trees (280 trees ha-1) and irrigating by gravity (74% of the area). Only 4.4% of the area of Los Antiguos is frost protected, as growers rely strongly on the moderating effect of Lake Buenos Aires. Frost control systems are absent in Comodoro Rivadavia because the established orchards are located next to the sea, in an area with low risk of frost. The frost-protected area is 49% in Sarmiento, 35% in Esquel and 57% in LVCHR. Fruit are harvested from November (LVCHR) to the end of January (Los Antiguos and Esquel), and the harvest-only labour demand during the 2004/2005 season was 100,000 h. In that season, seven packinghouses exported 390 t (45% of the total production) to Europe. Most orchards have not yet reached their mature stage and new ones are being established. Therefore, fruit volumes will continue to increase and shortages of labour and packing facilities may become a constraint

Sensitivity of global soil carbon stocks to combined nutrient enrichment

Soil stores approximately twice as much carbon as the atmosphere and fluctuations in the size of the soil carbon pool directly influence climate conditions. We used the Nutrient Network global change experiment to examine how anthropogenic nutrient enrichment might influence grassland soil carbon storage at a global scale. In isolation, enrichment of nitrogen and phosphorous had minimal impacts on soil carbon storage. However, when these nutrients were added in combination with potassium and micronutrients, soil carbon stocks changed considerably, with an average increase of 0.04 KgCm−2 year−1 (standard deviation 0.18 KgCm−2 year−1). These effects did not correlate with changes in primary productivity, suggesting that soil carbon decomposition may have been restricted. Although nutrient enrichment caused soil carbon gains most dry, sandy regions, considerable absolute losses of soil carbon may occur in high‐latitude regions that store the majority of the world's soil carbon. These mechanistic insights into the sensitivity of grassland carbon stocks to nutrient enrichment can facilitate biochemical modelling efforts to project carbon cycling under future climate scenarios