scholarly journals Predicted Crop Value for Nectarines and Cling Peaches of Different Harvest Season as a Function of Crop Load

HortScience ◽  
2007 ◽  
Vol 42 (2) ◽  
pp. 239-245 ◽  
Author(s):  
Gabino H. Reginato ◽  
Víctor García de Cortázar ◽  
Terence L. Robinson
Keyword(s):  
Size Distribution ◽  
Field Experiments ◽  
Fruit Size ◽  
Tree Size ◽  
Crop Load ◽  
Early Season ◽  
Yield Efficiency ◽  
Late Season ◽  
Wide Range ◽  
Fruit Load

Several field experiments to assess the effect of tree size and crop load on fruit size and yield efficiency were conducted in cling peach and nectarine orchards of different harvest seasons in Chile. Trees were randomly selected in each orchard and then hand-thinned at the beginning of pit hardening to a wide range of crop loads. The fraction of above-canopy photosynthetically active radiation (PAR) intercepted by the canopy (PAR i) was determined at harvest. All fruits were counted and weighed and average fruit weight calculated. Crop load and yield were normalized by tree size measured by intercepted PAR i. For each orchard, the relationship between crop load and fruit size or crop load and yield efficiency was assessed by regression analysis. Fruit size distribution was calculated from fruit size adjusted for fruit load assuming a normal fruit size distribution and valued according to shipment date and price obtained from a Chilean export company. Using crop load as a covariate, fruit size adjusted for crop load was compared for nectarine and peach cultivars. Fruit size adjusted for fruit load and yield efficiency was greater with late season cultivars than the early or midseason cultivars. Predicted crop value (PCV), normalized in terms of PAR intercepted, was calculated for all the cultivars. Large differences in predicted crop value were found for early, midseason, and late ripening nectarines. Early and late ripening cultivars had the highest predicted crop value, especially at lower crop loads and larger fruit sizes. The early season cultivars had high crop value as a result of higher fruit prices, whereas the late season cultivar had high crop value as a result of higher production. With cling peaches, the early season cultivar ‘Jungerman’ had a lower predicted crop value than the late season cultivars ‘Ross’ and ‘Davis’. For cling peaches, the highest PCV was achieved at a relatively high crop load with high yield and small fruit size.

scholarly journals Predicted Crop Value for a Cling Peach and Three Nectarines of Different Harvest Seasons as a Function of Crop Load

HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 995C-995
Author(s):  
Gabino Reginato ◽  
Terence Robinson ◽  
Victor Garcia de Cortazar
Keyword(s):  
Size Distribution ◽  
Field Experiments ◽  
Fruit Size ◽  
Fruit Weight ◽  
High Yield ◽  
Crop Load ◽  
Yield Efficiency ◽  
Small Fruit ◽  
Wide Range ◽  
On Farm

Several field experiments to assess the effect of tree size and crop load on fruit size and yield were conducted in a `Ross' cling peach orchard and in three nectarine orchards of different harvest seasons in Chile. Trees were randomly selected in each orchard and then hand-thinned at the beginning of pit hardening to a wide range of crop loads. The fraction of above-canopy photosynthetically active radiation intercepted by the canopy (PARi) was determined at harvest and all fruits were counted, weighted, and average fruit weight calculated. Cropload and yield were expressed in terms of fraction of PARi. Data on farm gate prices for export fruit of different sizes and export dates were obtained from a Chilean export company. For each orchard, the relationship between cropload and fruit size or cropload and yield efficiency was assessed by regression analysis. Fruit size distribution was calculated from adjusted fruit size assuming a normal fruit size distribution and valued according to shipment date and price. Using crop load as a covariate, fruit size adjusted for cropload was calculated for each nectarine orchard. Differences in adjusted fruit size and yield efficiency were detected among cultivars. Predicted crop value, normalized in terms of PARi intercepted, was calculated for all the cultivars. Large differences in predicted crop value were found for early, mid-season, and late-ripening nectarines. The early and late ripening cultivars showed the highest predicted crop value, especially at lower crop loads and larger fruit sizes. On the other hand, `Ross' cling peach showed its highest crop value at a medium crop load with high yield and relatively small fruit size. (Funded by FONDECYT grant 1930695.)

scholarly journals Estimating Apple Fruit Size Distribution from Early-season Fruit Diameter Measurements

HortScience ◽  
2019 ◽  
Vol 54 (11) ◽  
pp. 1947-1954
Author(s):  
Richard P. Marini ◽  
James R. Schupp ◽  
Tara Auxt Baugher ◽  
Robert Crassweller
Keyword(s):  
Size Distribution ◽  
Fruit Size ◽  
Apple Fruit ◽  
Fruit Weight ◽  
Regression Equations ◽  
Full Bloom ◽  
Actual Distribution ◽  
Early Season ◽  
Large Size ◽  
Fruit Diameter

In three experiments, diameters of apples representing 7% to 30% of the fruit on a tree were measured at ≈60 days after full bloom. Using previously published regression equations, the early-season fruit diameter values were used to estimate apple fruit weight at harvest (FWH). At harvest, all fruit on sample trees were weighed and the distributions of estimated FWH for fruit measured early in the season were compared with distributions of the actual FWH for whole trees. Actual FWH was normally distributed for only one of the three experiments. Although the estimated mean FWH averaged for the 10 trees was within 9% of the actual mean FWH for all three experiments, the distribution of estimated FWH differed significantly from the actual distribution for all three experiments. All fruit were then assigned to appropriate commercial fruit sizes or box counts (number of fruit/19.05 kg). Fruit size tended to peak on the same four box counts for the estimated and actual populations, but the estimated populations had too few fruits in the small- and large-size box counts. Using early-season estimates of FWH, commercial apple growers and packers can predict fairly accurately the percentage of the crop that will fall into the peak box counts, but a more accurate early-season estimate of the fruit size distribution will likely require measuring 50% of the fruit on a tree.

scholarly journals Optimizing Continuous Canopy Shakers for Late Season `Valenica' Harvest

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 885A-885
Author(s):  
Richard S. Buker* ◽  
Jackie K. Burns ◽  
Fritz M. Roka
Keyword(s):  
Operating Conditions ◽  
Tree Size ◽  
Mature Fruit ◽  
Fruit Removal ◽  
Crop Load ◽  
Immature Fruit ◽  
Late Season ◽  
Southern Site ◽  
Mechanical Harvester

Continuous canopy shakers (CCS) were developed in the late 90's and have been used to commercially harvest citrus in Florida. A viable mechanical harvester in Florida must be able to selectively remove mature `Valencia' fruit. A study was conducted to evaluate the effect of operating conditions on mature and immature fruit removal during the 2003 harvest season. The study was conducted in the southern flat woods and northern ridge areas. The study treatments were completely random and replicated four times. The CCS treatments were 145, 215, 230, and 245 cycles per minute (cpm) and a hand picked control. The harvest occurred on 17 and 19 June at the southern and northern sites, respectively. Mature fruit removal linearly increased from 95.7% to 97.9% between 145 and 245 cpm, respectively. Varying the operating ranges significantly influenced mature fruit removal in the southern flat woods site. The trees at the southern site were taller (>4m), and had a larger crop load. At the northern ridge site where trees were smaller, varying the CCS operating ranges did not significantly influence mature fruit removal. Immature fruit removal was influenced by the operating ranges. Immature fruit removal was increased at least 22% over hand picked controls. The results were interpreted to indicate the frequency of CCS is dependent on tree size. The initial selectivity of the CCS was not equal to hand picking.

scholarly journals THE EFFECTS OF FOLIARLY APPLIED CALCIUM ON FRUIT CALCIUM, FIRMNESS, SOLUBLE SOLIDS, STORABILITY AND ORGANOLEPTIC QUALITY OF `CRESTHAVEN' PEACH

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1147c-1147
Author(s):  
J. Anthony Hopfinger ◽  
Donald W. Shaffner ◽  
Eric D. Cubberley
Keyword(s):  
Size Distribution ◽  
Profile Analysis ◽  
Fruit Size ◽  
Storage Period ◽  
Soluble Solids ◽  
High Rate ◽  
Calcium Treatment ◽  
Crop Load ◽  
Texture Profile

Both Cacl2 and Nutrical (a trihydroxyglutarate chelate) were foliarly applied at rates of 1.8 and 5.5 Cacl2/ha/season and 1.5 and 4.5 l/ha/season, respectively. Applications were made starting at shuck split and repeated at 2 week intervals until harvest. Neither calcium treatment had an effect on fruit size and size distribution. Fruit size was directly related to crop load. Calcium chloride application had the most pronounced effect on increasing the red over-color of `Cresthaven' peaches with Nutrical intermediate compared to the control. The high rate of Nutrical increased flesh calcium levels at harvest by 75-100 PPM. Instron Texture Profile Analysis indicated that any calcium treatment significantly increased the hardness of the peach. Nutrical at 4.5 l/ha/season improved hardness 2-fold compared to the controls. The improved hardness was maintained throughout the 6 week storage period.

Carbamothioate and Chloroacetamide Herbicides for Woolly Cupgrass (Eriochloa villosa) Control in Corn (Zea mays)

1991 ◽  
Vol 5 (2) ◽  
pp. 331-336 ◽  
Author(s):  
Joseph F. Schuh ◽  
R. Gordon Harvey
Keyword(s):  
Zea Mays ◽  
Field Experiments ◽  
Weather Conditions ◽  
Early Season ◽  
Application Timing ◽  
Late Season ◽  
Adverse Weather Conditions ◽  
Adverse Weather ◽  
Woolly Cupgrass ◽  
Eriochloa Villosa

Field experiments were conducted to compare herbicides applied preplant incorporated (PPI), preplant incorporated/preemergence (PPI/PRE), and preplant incorporated/early postemergence (PPI/early POST) to control woolly cupgrass in corn. Although good early-season control of woolly cupgrass from PPI cycloate plus cyanazine, EPTC plus dietholate or SC-0058, and butylate plus cyanazine sometimes was observed, middle- and/or late-season control was often limited. Generally, better woolly cupgrass control and higher corn yields were obtained from split PPI/PRE applications rather than from single PPI applications of alachlor, metolachlor, and acetochlor. The highest and most consistent full-season woolly cupgrass control resulted when cycloate or EPTC plus dietholate applied PPI was followed by cyanazine plus either pendimethalin, alachlor, metolachlor, or acetochlor applied early POST. However, in 1989 adverse weather conditions near the early POST application timing injured corn and reduced yields.

Irrigation and crop load interactions in relation to pear yield and fruit-size distribution

2000 ◽  
Vol 75 (5) ◽  
pp. 555-561 ◽  
Author(s):  
A. Naor ◽  
M. Peres ◽  
Y. Greenblat ◽  
I. Doron ◽  
Y. Gal ◽  
...  
Keyword(s):  
Size Distribution ◽  
Fruit Size ◽  
Crop Load

scholarly journals Cotton Tolerance to Hoplolaimus columbus and Impact on Population Densities

Plant Disease ◽  
2005 ◽  
Vol 89 (6) ◽  
pp. 649-653 ◽  
Author(s):  
S. R. Koenning ◽  
D. T. Bowman
Keyword(s):  
Field Experiments ◽  
Cultivar Differences ◽  
Tolerance Index ◽  
Population Densities ◽  
Cotton Lint ◽  
Early Maturity ◽  
Early Season ◽  
Late Season ◽  
Cotton Lint Yield ◽  
Hoplolaimus Columbus

Glyphosate-tolerant transgenic-cotton cultivars were evaluated for tolerance to Hoplolaimus columbus in field experiments conducted from 2001 to 2003. The studies were arranged in a split-plot design that included treatment with 1,3-dichloropropene at 42 liter/ha to establish fumigated versus nonfumigated subplots with cultivars as whole plots. Cotton cultivars were divided by relative maturity into two separate but adjacent experiments in order to facilitate cotton defoliation, with 10 early-maturity and 5 late-maturity cultivars. Fumigation was effective in suppressing H. columbus population densities and increased cotton lint yield. The cultivar-fumigation interaction was significant for early-season cotton cultivars but not for late-season cultivars. A tolerance index ([yield of nontreated/yield of treated] × 100) was used to compare cultivar differences. Both groups of cultivars expressed significant levels of tolerance to H. columbus, but late-season cultivars tended to yield more than early-season cultivars in infested fields.

scholarly journals Organic fertilization and crop load in yield and quality of organic nectarines in Italy

2021 ◽  
Vol 43 (5) ◽  
Author(s):  
Caroline Farias Barreto ◽  
Luis Eduardo Correa Antunes ◽  
Moreno Toselli ◽  
Elena Baldi ◽  
Giovambattista Sorrenti ◽  
...  
Keyword(s):  
Environmental Sustainability ◽  
Fruit Size ◽  
Fertilization Rate ◽  
Soluble Solids ◽  
Organic Fertilization ◽  
Crop Load ◽  
Po Valley ◽  
Set Up ◽  
Fruit Mass ◽  
Fruit Load

Abstract Organic fertilization in orchards aims at increasing soil fertility, at impacting plant productivity and environmental sustainability. This study aimed at verifying the effects of organic fertilization and fruit load on two nectarine cultivars with high and low fruit loads. The experiment was carried out in an orchard under organic management in Fratta Terme, Po valley, in northeastern Italy. Nectarine cultivars Big Top and Carene, implemented in 2017 and grafted onto GF677, were used. Three levels of compost (0, 20 and 40 t dw ha-1) were combined with two fruit loads (low and high) to set up a factorial experimental design with two factors and four randomized replicates. Compost was incorporated at 20 cm depth. The following parameters were evaluated: nitrate- and ammonium- N concentrations in soil at 20 - 40 cm depth, macro and micronutrients in leaves, tree yield, number of fruits, fruit mass and diameter, soluble solids and pulp firmness. The supply of compost enhanced nitrate-N release in soil. In both cultivars, macro- and micronutrient concentrations in leaves were not affected by organic fertilization or fruit load, except for iron, which increased as a consequence of the compost supply. Low crop load induced higher fruit size in both varieties, a fact that was observed after pit hardening. However, the organic fertilization rate did not influence tree yield, fruit mass and soluble solids.

scholarly journals Growth and Yield of Watermelon on Polyethylene Mulch with Different Spacings and Nitrogen Rates

HortScience ◽  
2005 ◽  
Vol 40 (2) ◽  
pp. 366-369 ◽  
Author(s):  
Smiljana Goreta ◽  
Slavko Perica ◽  
Gvozden Dumicic ◽  
Lovre Bucan ◽  
Katja Zanic
Keyword(s):  
Size Distribution ◽  
Field Experiments ◽  
Fruit Size ◽  
Fruit Weight ◽  
Growth And Yield ◽  
Planting Density ◽  
Plant Spacing ◽  
N Rates ◽  
Polyethylene Mulch ◽  
Leaf N

Suggested watermelon planting densities and N rates vary on a large scale, indicating that there is insufficient knowledge about their effects. Therefore, the objective of this study was to evaluate the effects of N rate and planting density on growth, yield and quality of watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai] grown on black polyethylene mulch. The field experiments with `Crimson Sweet' watermelon were conducted in two climatologically different growing regions. The treatments were factorial combinations of three in-row plant spacings (0.5, 1.0, and 1.5 m) and three N rates (115, 195, and 275 kg·ha-1). Part of the N (35 kg·ha-1) was applied preplant and the remainder was fertigated. Vine length increased linearly up to 7 weeks after planting (WAP) as N rate increased from 115 to 275 kg·ha-1, and up to 9 WAP as plant spacing increased from 0.5 to 1.5 m. Total and marketable yields per ha or per plant did not increase with N rates above 115 kg·ha-1. Average fruit weight and fruit size distribution were generally unaffected by N rate. Leaf N concentration increased as N rate increased, although leaf N concentrations at the lowest N rate (115 kg·ha-1) even at 9 WAP were relatively high (43.3 to 47.3 g·kg-1). Total and marketable yields per ha were linearly decreased with an increase in plant spacing from 0.5 to 1.5 m, and the same was noticed with the total and marketable number of fruit per ha. With increased plant spacing average fruit weight increased and fruit size distribution shifted to larger categories.

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