scholarly journals A Heat Unit Model to Predict Growth and Development of Muskmelon to Anthesis of Perfect Flowers

1996 ◽  
Vol 121 (2) ◽  
pp. 274-280 ◽  
Author(s):  
Sylvie Jenni ◽  
Daniel C. Cloutier ◽  
Gaétan Bourgeois ◽  
Katrine A. Stewart
Keyword(s):  
Cucumis Melo ◽  
Dry Weight ◽  
Developmental Time ◽  
Base Temperature ◽  
Heat Unit ◽  
Independent Variables ◽  
Air Temperatures ◽  
Unit Model ◽  
Soil Temperatures ◽  
Unit Formula

Growth of `Earligold' muskmelon (Cucumis melo L.), expressed as plant dry weight from transplanting to anthesis, could be predicted using a multiple linear regression based on air and soil temperatures for 11 mulch and rowcover combinations. The two independent variables of the regression model consisted of a heat unit formula for air temperatures, with a base temperature of 14C and a maximum reduced threshold of 40C, and a standard growing-degree day formula for soil temperatures with a base temperature of 12C. Based on 2 years of data, 86.5% of the variation in the dry weight (on a log scale) could be predicted with this model. The base temperature for predicting developmental time to anthesis of perfect flowers was established at 6.8C and the thermal time ranged between 335 and 391 degree days in the 2 years of the experiment.

scholarly journals A Heat Unit Model to Predict Growth and Development of Muskmelon (Cucumis melo var. reticulatus Naud.) to Anthesis

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 790D-790
Author(s):  
S. Jenni ◽  
D.C. Cloutier ◽  
G. Bourgeois ◽  
K.A. Stewart
Keyword(s):  
Cucumis Melo ◽  
Dry Weight ◽  
Base Temperature ◽  
Degree Days ◽  
Heat Unit ◽  
Air Temperatures ◽  
Unit Model ◽  
Dependent Variables ◽  
Soil Temperatures ◽  
Unit Formula

Plant dry weight of muskmelon transplants to anthesis could be predicted from a multiple linear regression based on air and soil temperatures prevailing under 11 mulch and rowcover combinations. The two dependent variables of the regression model consisted of a heat unit formula for air temperatures with a base temperature of 14C and a maximum-reduced threshold at 40C, and a standard growing-degree-day formula for soil temperatures with a base temperature of 12C. Based on 2 years of data, 86.5% of the variation in the dry weight (on a log scale) could be predicted with this model. The base temperature for predicting time to anthesis of muskmelon transplants was established at 6.8C and the thermal time ranged between 335 and 391 degree-days during the 2 years of the experiment.

scholarly journals Use of Belowground Growing Degree Days to Predict Rooting of Dormant Hardwood Cuttings of Populus

2004 ◽  
Vol 53 (1-6) ◽  
pp. 154-160 ◽  
Author(s):  
R. S. Zalesny ◽  
E. O. Bauer ◽  
D. E. Riemenschneider
Keyword(s):  
Populus Deltoides ◽  
Dry Weight ◽  
Growing Degree Days ◽  
Base Temperature ◽  
Degree Days ◽  
Planting Dates ◽  
Growing Period ◽  
Period 2 ◽  
Soil Temperatures ◽  
Total Dry Weight

Abstract Planting Populus cuttings based on calendar days neglects soil temperature extremes and does not promote rooting based on specific genotypes. Our objectives were to: 1) test the biological efficacy of a thermal index based on belowground growing degree days (GDD) across the growing period, 2) test for interactions between belowground GDD and clones, and 3) identify beneficial planting windows based on combinations of genotypes and belowground GDD. We tested two clones of Populus deltoides Bartr. ex Marsh (D133, D134) and four hybrid clones of P. deltoides × P. maximowiczii A. Henry (DM101, DM105, NC14105, NC14107). Cuttings, 20 cm long, were planted in randomized complete blocks at 15- × 15-cm spacing across three planting dates during 1999 at Alexandria, Minnesota, USA (45.9°N, 95.4°W) and Fertile, Minnesota, USA (47.3°N, 96.2°W). Temperatures at 20 cm belowground were converted to GDD with a base temperature of 10°C. We measured root, top, and total dry weight, along with number of roots after 14 d of growth. Relatively warmer and cooler soil temperatures promoted rooting for the cottonwoods and hybrids, respectively. We recommend planting after reaching a threshold of 163 belowground GDD for P. deltoides clones and planting before reaching a threshold of 173 belowground GDD for P. deltoides × P. maximowiczii clones.

MODIFICATION OF THE HEAT UNIT FORMULA FOR PEAS

1962 ◽  
Vol 42 (1) ◽  
pp. 15-21 ◽  
Author(s):  
G. W. Hope
Keyword(s):  
Daily Maximum ◽  
Base Temperature ◽  
Heat Unit ◽  
Yearly Variation ◽  
Coefficients Of Variation ◽  
Maximum Temperatures ◽  
Unit Formula

The yearly variation in computed heat unit requirements of Perfection peas was reduced by modifying the method of deriving the units. Coefficients of variation of heat unit sums derived from daily means were lowest when daily maximum temperatures in excess of 60°F. were equated to 60° and when a base temperature of 36°F. was subtracted from the mean.Heat unit sums obtained from daily maxima were as homogeneous as those obtained from daily means.

scholarly journals Onset of Flowering in Biennial and Perennial Garden Plants

2012 ◽  
pp. 85-132
Author(s):  
F. T. Last ◽  
A. M.I Roberts
Keyword(s):  
Late Winter ◽  
Base Temperature ◽  
Early Winter ◽  
Species Trees ◽  
Air Temperatures ◽  
Winter Temperatures ◽  
Soil Temperatures ◽  
Significant Temperature ◽  
Spring Temperatures ◽  
Delayed Flowering

Observations were made weekly over a period of 30 years of 208 species (trees, shrubs, herbaceous plants and geophytes) from more than 1,000 growing in a garden located 18km east of the Royal Botanic Garden Edinburgh (RBGE), Scotland (lat. 55º 56ʹN: long. 3º 09ʹW). Of these species, 27 were British native or naturalised.The First Flowering Dates (FFD) of 67 species were without significant temperature association with variable weather; the FFDs of the other 141 species reflected, in contrast, the net outcome of ‘major’ associations with late winter/spring temperatures and smaller impacts of autumn/early winter temperatures. Increases in late winter and spring temperatures advanced the onset of flowering in the current year; in contrast, increases in autumn and early winter temperatures tended to be associated with delayed flowering in the following year.With stepwise regression, penalised signal regression and thermal-time models, it was possible to identify species with ‘strong’ associations with both air and soil temperatures and species with ‘weak’ associations with either air or soil temperatures.Thermal-time models for each of 120 species, whose FFDs were associated with temperature, enabled the characterisation of (1) base temperatures, Tb(°C), at, and above which, development towards open flowers is possible; and (2) thermal constants (degree days accumulated between the start of development and the onset of flowering). Together these attributes suggested that each base temperature cohort has species with widely different degree-day requirements. Between 1978 and 2007 mean air temperatures significantly increased by 0.080°C, 0.044°C and 0.026°C yrˉ¹ in the first, second and third quarters; soil temperatures increased by 0.060ºCyrˉ¹in the first quarter. Over the 30-year period, the trends in flowering showed the early (February/March) flowering species flowering c. 24 days sooner; the later flowering species (April/May) advanced by only c. 12 days.

scholarly journals Influence of Various Polyethylene Mulch Colors on Growth and Development of `Vates' Collards

HortScience ◽  
1997 ◽  
Vol 32 (4) ◽  
pp. 600D-600
Author(s):  
J.M Kemble ◽  
J. Brown ◽  
E. Simonne
Keyword(s):  
Growth And Development ◽  
Soil Depth ◽  
Dry Weight ◽  
Base Temperature ◽  
Fresh Weight ◽  
Degree Days ◽  
Marketable Yield ◽  
Soil Temperatures ◽  
Polyethylene Mulch ◽  
Final Harvest

The effect of various mulch colors (black, yellow, red, blue, white, and aluminum) on growth and development of `Vates' collards was evaluated in Fall 1996 at the E.V. Smith Research Center in Shorter, Ala. Black polyethylene mulch was installed onto raised, fumigated beds, then sprayed with a 1: 2 (v/v) mixture of exterior oil-based enamel paint to paint thinner with one of the five mulch colors listed. Five-week-old plants were transplanted into beds. Beginning two weeks after transplanting and continuing every other week thereafter, heads were harvested to determine head fresh weight and dry weight. Hourly soil temperatures at 10 cm soil depth were recorded and growing degree days (GDDs) with a base temperature of 4.4 °C were calculated. At two weeks after transplanting, average head fresh and dry weight were highest for the aluminum-colored treatment with head fresh (24.7 and 12.3 g, respectively) and dry weights (2.7 and 1.3 g, respectively) twice that of the yellow treatment (P ≤ 0.05). By four weeks after transplanting and up through the final harvest, marketable yield and average head fresh weights did not differ among the treatments (17,900 kg/ha, 1.4 kg per head, respectively). The red and black mulch treatments accumulated more GDDs than the other treatments, but total marketable yields did not differ among any treatments.

Muskmelon (Cucumis melo L.) Responses to Floating Row-cover

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 475b-475
Author(s):  
Hassan Elattir ◽  
Mohamed Derouich ◽  
Abdelhaq Hanafi
Keyword(s):  
Sandy Soil ◽  
Cucumis Melo ◽  
Block Design ◽  
The Other ◽  
Deep Soil ◽  
Air Temperatures ◽  
Randomized Block Design ◽  
Soil Temperatures ◽  
Direct Seeded ◽  
Cucumis Melo L

Two groups of Cucumis melo L. cv. Galia F1 were seeded on 10 Jan. 1994. The first group was direct-seeded in a loam sandy soil and covered at the same time with perforated polyethylene floating rowcover. The other group was seeded in a nursery and the muskmelon seedlings were transplanted and covered by perforated polyethylene in 7 Feb. 1994. The experiment was conducted in the Complexe Horticole experiment station located 17 km southeast of Agadir in a randomized block design with four treatments and four replications. Floating rowcover increased minimal and maximal air temperatures by 0.92 to 2.43 °C and 3,71 to 6.99 °C, respectively. Ten centimeters deep, soil temperatures of covered treatments were higher by 0.35 to 0.57 °C and 0.71 to 1 °C at 7 AM and 4.30 PM respectively. Plant early yield recorded in the four treatments: transplanted muskmelon with floating rowcover, direct seeded muskmelon with floating rowcover, transplanted muskmelon without cover and direct seeding without cover was 2003.9 g, 1219.2 g, 500.9 g, and 60.6 g respectively.

scholarly journals Predicting Yield and Time to Maturity of Muskmelons from Weather and Crop Observations

1998 ◽  
Vol 123 (2) ◽  
pp. 195-201 ◽  
Author(s):  
Sylvie Jenni ◽  
Katrine A. Stewart ◽  
Gaétan Bourgeois ◽  
Daniel C. Cloutier
Keyword(s):  
Total Yield ◽  
Developmental Time ◽  
Daily Maximum ◽  
Base Temperature ◽  
Heat Unit ◽  
Data Set ◽  
Simple Method ◽  
Fruit Maturity ◽  
Richards Function ◽  
Maximum Temperatures

A simple method to predict time from anthesis of perfect flowers to fruit maturity (full slip) and yield is presented here for muskmelon (Cucumis melo L.) grown in a northern climate. Developmental time for individual muskmelons from anthesis to full slip could be predicted from several heat unit formulas, depending on the temperature data set used. When temperature at 7.5 cm above soil level was used, the heat unit formula resulting in the lowest coefficient of variation (cv=6.9%) accumulated daily average temperatures with a base temperature of 11 °C and an upper threshold of 25 °C. With temperatures recorded at a meteorological station located 2 km from the experimental field, the method showing the lowest cv (8.9%) accumulated daily maximum temperatures with a base temperature of 15 °C. This latter method was improved by including a 60-degree-day lag for second cycle fruit. The proportion of fruit volume at full slip of 22 fruit from the first cycle could be described by a common Richards function (R2=0.99). Although 65% of the plants produced two fruit cycles, fruit from the first cycle represented 72% of total yield in terms of number and mass. The blooming period of productive flowers lasted 34 days, each cycle overlapping and covering an equal period of 19 days. Counting the number of developing fruit >4 cm after 225 degree days from the start of anthesis (when 90% of the plants have at least one blooming perfect flower) could rapidly estimate the number of fruit that will reach maturity.

scholarly journals SPUNBONDED FABRIC COVERS ALTER EARLY SEASON GROWTH AND FRUIT SET IN CRANBERRY

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1105c-1105
Author(s):  
Elden J. Stang ◽  
John Klueh
Keyword(s):  
Fruit Set ◽  
Leaf Tissue ◽  
Leaf Size ◽  
Dry Weight ◽  
Vaccinium Macrocarpon ◽  
Anthocyanin Content ◽  
Shoot Dry Weight ◽  
Air Temperatures ◽  
Polypropylene Fabric ◽  
Soil Temperatures

Spunbonded polypropylene fabric covers were applied over mature `Searles' cranberry (Vaccinium macrocarpon Ait. in the field during dormancy in 1989. Covers were selectively removed at 3 week intervals in April, May and early June after onset of growth. Plant canopy air temperatures under fabric were 5 to 6C higher than in exposed controls. Temperature differences up to 17C were measured in early June. Soil temperatures did not differ from the control until late May. Earlier greening of leaf tissue resulted in increased photosynthetic rates earlier in the growing season under fabric covers. Subsequent shoot dry weight was increased 5%; leaf size was not affected. A trend to increased fruit set (4 to 6%) with fabric cover treatments was observed when covers were applied for 6 or 9 weeks. Total fruit yield and anthocyanin content were not appreciably influenced by fabric covers.

scholarly journals Growth and Development of Basil Species in Response to Temperature

HortScience ◽  
2019 ◽  
Vol 54 (11) ◽  
pp. 1915-1920
Author(s):  
Kellie J. Walters ◽  
Christopher J. Currey
Keyword(s):  
Air Temperature ◽  
Growth And Development ◽  
Dry Weight ◽  
Base Temperature ◽  
Branch Number ◽  
Sweet Basil ◽  
Air Temperatures ◽  
Appearance Rate ◽  
Response To Temperature ◽  
Increasing Temperature

Basil (Ocimum sp.) is the most popular fresh culinary herb, but the effects of air temperature on growth and development of basil have not been well characterized. Our objective was to quantify the effects of air temperature on growth and development of three basil species. Seedlings of sweet basil (Ocimum basilicum ‘Nufar’), holy basil (O. tenuiflorum), and lemon basil (O. ×citriodorum ‘Lime’ and O. basilicum ‘Sweet Dani’) were placed in five different growth chambers with target air temperatures of 11, 17, 23, 29, or 35 °C. After 3 weeks, chlorophyll fluorescence (Fv/Fm), plant height, node and branch number, fresh and dry weight, and flowering data were recorded. For all species, Fv/Fm increased as temperature increased to 17 or 23 °C, then plateaued, whereas height increased with temperature to 23 or 29 °C. Also, the percentage of plants with flowers or flower buds increased with temperature to 17 or 23 °C for all species, with the exception of sweet basil, of which all plants were vegetative and node appearance rate was calculated. Sweet basil node appearance increased from 0.03 to 0.30 node/day as the temperature increased from 11 to 29 °C. Fresh weight gain increased with increasing temperature to 29 °C, but then decreased at 35 °C. Data from plants grown within the linear air temperature range were used to develop models for calculating the base temperature (Tb) and predicting growth in response to air temperature. These models can be applied by commercial producers to schedule crops and predict yields.

scholarly journals Soil Temperature and Precipitation Affect the Rooting Ability of Dormant Hardwood Cuttings of Populus

2005 ◽  
Vol 54 (1-6) ◽  
pp. 47-58 ◽  
Author(s):  
R. S. Zalesny ◽  
R. B. Hall ◽  
E. O. Bauer ◽  
D. E. Riemenschneider
Keyword(s):  
Soil Temperature ◽  
Root Length ◽  
Dry Weight ◽  
Precipitation Event ◽  
Base Temperature ◽  
Planting Dates ◽  
Growing Period ◽  
Rooting Ability ◽  
Temperature And Precipitation ◽  
Soil Temperatures

Abstract In addition to genetic control, responses to environmental stimuli affect the success of rooting. Our objectives were to: 1) assess the variation in rooting ability among 21 Populus clones grown under varying soil temperatures and amounts of precipitation and 2) identify combinations of soil temperature and precipitation that promote rooting. The clones belonged to five genomic groups ([P. trichocarpa Torr. & Gray x P. deltoides Bartr. ex Marsh] x P. deltoides ‘BC’; P. deltoides ‘D’; P. deltoides x P. maximowiczii A. Henry ‘DM’; P. deltoides x P. nigra L. ‘DN’; P. nigra x P. maximowiczii ‘NM’). Cuttings, 20 cm long, were planted in Iowa and Minnesota, USA, in randomized complete blocks at 1.2- x 2.4-m spacing across three planting dates during 2001 and 2002. Soil temperatures were converted to belowground growing degree days (GDD) (base temperature = 10°C) accumulated over 14 days. Genomic groups responded similarly for root dry weight, number of roots, total root length, and mean root length, that increased as belowground GDD increased. Belowground GDD and precipitation governed rooting throughout the 14-d growing period. A minimum of four days above 14°C, along with sufficiently dispersed precipitation (e.g. no more than 3 d without a precipitation event), were needed to sustain aboveaverage rooting. Therefore, we recommend using a base temperature of 14°C for future models estimating belowground GDD in northern temperate zones.

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