scholarly journals Temperatura-base e soma térmica para a Zínia ‘Profusion Cherry’ envasada cultivada em ambiente protegido

2016 ◽  
Vol 21 (3) ◽  
pp. 376
Author(s):  
Charleston Gonçalves ◽  
Carlos Eduardo Ferreira Castro ◽  
Mário José Pedro Júnior ◽  
Maria Luiza Sant’anna Tucci
Keyword(s):  
New Species ◽  
Thermal Time ◽  
Base Temperature ◽  
Degree Days ◽  
Consumer Market ◽  
Open Flower ◽  
Lack Of Information ◽  
Protected Cultivation

The growing of consumer market demands introduction of new species of flowers and cultivars primarily for production under protected cultivation. The zinnia by the quickness of production can be regarded as an alternative, however demand studies by the lack of information in the literature. We evaluated the duration of different periods, the base temperature and thermal accumulation, expressed as degree-days for the potted zinnia ‘Profusion Cherry’, conducted under protected cultivation for different phenological subperiods. The test was conducted in a greenhouse covered with plastic and closed laterally with shading-net and the duration of subperiods were made to twenty times after sowing. The base temperature was determined by relative development and values-based temperature and thermal time in degree-days (DD). The results for the different phases were, respectively: first open flower-planting: 4.1 °C and GD 838, first open flower - 50% of flowers open: 3.0 °C and 184 GD and 50% of flowers open - senescence: 6.9 °C and 238 GD.

scholarly journals Prediction of Development of Asiatic Lilies Based on Air Temperature and Thermal Units

HortScience ◽  
2003 ◽  
Vol 38 (6) ◽  
pp. 1100-1103 ◽  
Author(s):  
J. Steininger ◽  
C.C. Pasian
Keyword(s):  
Linear Regression ◽  
Change Point ◽  
Prediction Error ◽  
Base Temperature ◽  
Point Model ◽  
Degree Days ◽  
Flower Bud ◽  
Open Flower ◽  
Average Prediction Error ◽  
Change Point Model

`Butter Pixie' and `Horizon' Asiatic lilies (Lilium spp.), were grown at several temperatures. The phenological events of visible shoot (VS), visible flower bud (VB), and open flower (OF) were recorded daily. Based on these events, phenophases from VS to VB (VS:VB), from VB to OF (VB:OF), and from VS to OF (VS:OF) were defined. Daily rates of development to complete a phenophase increased with temperature. Nonlinearity was obvious for all phenophases around 25 °C for `Horizon' and 27 °C for `Butter Pixie'. A piece-wise linear regression change point model was fitted to each dataset. The base temperature (Tb), the temperature at which the nonlinearity occurred (Ti), and the temperature for fastest development (To) could then be determined. Tb for the phenophase VS: OF was -0.4 °C for `Butter Pixie' and 3.0 °C for `Horizon'. Ti for `Butter Pixie' was 25.7 °C for VB:OF and 26.1 °C for the phenophase VS:OF. However, Ti for `Horizon' was found only for the phenophase VS:OF. To complete the phenophase VS:OF, 1102.2 degree days (°Cd) were predicted necessary for `Butter Pixie' and 833.2 °Cd for `Horizon'. Predicted time of events was compared with observed values. Subdividing VS:OF into VS:VB and VB:OF and using their respective Tb and TU reduced the average prediction error from 2.13 to 1.87 d for `Butter Pixie' and from 2.39 to 1.86 days for `Horizon'.

scholarly journals Base temperature, thermal time and phyllochron of escarole cultivation

2018 ◽  
Vol 36 (4) ◽  
pp. 466-472
Author(s):  
Denise Schmidt ◽  
Braulio O Caron ◽  
Oscar Valera ◽  
Daniela Meira ◽  
Daniele C Fontana ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Coefficient Of Variation ◽  
Regression Coefficient ◽  
Block Design ◽  
Thermal Time ◽  
Base Temperature ◽  
Degree Days ◽  
Randomized Block Design ◽  
Number Of Leaves ◽  
Santa Maria

ABSTRACT The objective of this study was to determine the base temperature of escarole and to apply in the phenological analysis of crop during four growing periods. The study was carried out with escarole (Chicorium endivia) ‘Escarola Lisa’ cultivar, at the Federal University of Santa Maria, campus Frederico Westphalen-RS. The experiment was performed in a randomized block design with four sowing periods (P1: 2/15/2015; P2: 04/29/2015, P3: 07/22/2015, P4: 10/16/2015) and 10 replicates, each replicate being one plant. The evaluations consisted of counting the number of leaves, performed three times a week after transplanting date until the harvesting point. To determine the base temperature, the following methods were used: standard deviation in degree-days (SDgd), standard deviation in days (SDd), coefficient of variation in degree-days (CVgd), coefficient of variation in days (CVd), regression coefficient (RC) and X-intercept. The base temperature for emission of two successive leaves in the escarole is 4.7°C, obtained by values of 4.0 and 5.5°C, observed in the SDgd and RC methods. For two leaves emission, the temperature between 16.6 and 27.8°C day leaf-1 is necessary.

scholarly journals Phenological behavior of feijoa accessions in their main diversity center

2020 ◽  
Vol 55 ◽  
Author(s):  
Fernando David Sánchez-Mora ◽  
Luciano Saifert ◽  
Marlise Nara Ciotta ◽  
Humberto Nunes Ribeiro ◽  
Luciane Isabel Malinovski ◽  
...  
Keyword(s):  
Fruit Ripening ◽  
Thermal Time ◽  
Growing Degree Days ◽  
Base Temperature ◽  
Degree Days ◽  
Germplasm Bank ◽  
Phenological Stages ◽  
Santa Catarina ◽  
Time Requirements ◽  
Acca Sellowiana

Abstract: The objective of this work was to identify the minimum base temperature (Tb) and the maximum base temperature (TB) to predict the thermal time for six phenological stages of feijoa (Acca sellowiana) accessions. During ten noncontinuous harvests (2004 to 2017), 247 feijoa accessions, maintained in the Feijoa Active Germplasm Bank, in São Joaquim, in the state of Santa Catarina, Brazil, had their data recorded for: initial sprouting (IS), initial flowering (IF), end of flowering (EF), beginning of harvest (BH), and end of harvest (EH). Tb and TB were estimated by the Arnold’s method of least variability, and the TT requirements were obtained by Ometto’s method. Tb at 7.76°C and TB at 17.0°C were necessary when feijoa plants started growing (IS stage) just after winter; and Tb at 10.6°C and TB at 19.5°C were the calculated values from IS until BH. The budding stage of the accessions began in the mid-September (50.6%); flowering occurred predominantly in November (90%); and harvest began in March and lasted until May. About 176 days, with 1,014.4 growing degree-days, are necessary to complete the productive cycle from IS until BH. The early, intermediary, and late fruit-ripening accessions show different thermal time requirements.

scholarly journals Temperature and Pseudobulb Size Influence Flowering of Odontioda Orchids

HortScience ◽  
2008 ◽  
Vol 43 (5) ◽  
pp. 1404-1409 ◽  
Author(s):  
Matthew G. Blanchard ◽  
Erik S. Runkle
Keyword(s):  
Constant Temperature ◽  
Thermal Time ◽  
Base Temperature ◽  
Time Model ◽  
Open Flower ◽  
Inflorescence Development ◽  
The Andes ◽  
Stress Symptoms ◽  
Leaf Necrosis ◽  
Thermal Time Model

Odontioda is a cool-growing, sympodial epiphytic genus of orchids originating from the Andes Mountains of South America. Several hybrids are commercially grown as potted flowering plants for their brightly colored flowers and compact growth habit. We quantified how constant and fluctuating day/night temperatures influenced inflorescence initiation, time from visible inflorescence (VI) to flower, and pseudobulb development. Odontioda George McMahon ‘Fortuna’ and Lovely Penguin ‘Emperor’ were grown at constant temperature set points of 14, 17, 20, 23, 26, or 29 °C and day/night (12 h/12 h) temperatures of 20/14, 23/17, 26/14, 26/20, 29/23, or 29/17 °C. Plants were grown in glass greenhouses under a 12-h photoperiod and a maximum irradiance of 500 μmol·m−2·s−1. Within 6 weeks, heat stress symptoms such as leaf necrosis were observed on plants grown at a day temperature of 26 °C or greater regardless of the night temperature. After 20 weeks, 90% or greater of both clones had a VI when grown at a constant temperature of 14 or 17 °C. Plants grown at a constant temperature of 17 °C had the greatest pseudobulb diameter with a mean increase of 3.5 to 4.0 cm. In all treatments, a minimum pseudobulb diameter was required for uniform inflorescence initiation; pseudobulbs with a diameter of 5.5 cm or greater developed a VI in 93% of plants. Data for time from VI to open flower were converted to a rate, and a thermal-time model relating temperature with inflorescence development was developed. The base temperature and thermal time for VI to flower in George McMahon ‘Fortuna’ and Lovely Penguin ‘Emperor’ were estimated at −0.1 °C and 1429 °C·d−1 and 0.8 °C and 1250 °C·d−1, respectively. This information could be used by commercial orchid growers to assist in producing potted flowering Odontioda orchids for specific market dates.

scholarly journals Base temperature as a function of genotype: a foundation for modeling phenology of temperate fruit species

2016 ◽  
Vol 37 (4) ◽  
pp. 1811
Author(s):  
Anzanello Rafael ◽  
Luiz Antonio Biasi
Keyword(s):  
Meteorological Data ◽  
Growing Season ◽  
Fruit Trees ◽  
Thermal Time ◽  
Base Temperature ◽  
Degree Days ◽  
Single Node ◽  
Fruit Species ◽  
Lower Base ◽  
Phenological Phases

To complete each phase of the growing season, plants must accumulate thermal time at lower base temperature (Tb). Little information exists on Tb variation between either fruit species or cultivars of the same species. We therefore aimed to determine the lower base temperature for contrasting genotypes in precocity of peach, plum, grape, pear, and kiwi. Twigs 25-35 cm long for the following cultivars: peach, Tropic Beauty (TB) and Eragil (ER); plum, Gulf Blaze (GB) and Letícia (LE); grape, Chardonnay (CH) and Cabernet Sauvignon (CS); pear, Smith (SM) and Packham’s (PA); and kiwi, Golden King (GK) and Hayward (HA) were collected in orchards in Veranópolis, RS Estate, on 06/13/2014, with 0 h at temperatures ? 7.2°C (chilling hours; HC) in the field. Intact twigs packed in black plastic film were subjected to 1,008 HC at 0°C in incubators to overcome dormancy and then transferred to temperatures of 2, 4, 6, 8, 10, and 12°C on single-node cuttings planted in phenolic foam to define effective heat temperature for the genotypes. Over 110 d, budburst of the buds was evaluated in 2-3-d intervals in the green-tip stage. The resulting inverse data of number of days to budburst (1/days to budburst) was inserted into regression curves to estimate Tb for each genotype. Historical phonological series comprised of 10 years for the analyzed cultivars and meteorological data of the cultivation sites were used to determine thermal time (degree-days) for the fruit trees during the growing season, considering different phenological phases. Temperate fruit species exhibited different Tb behaviors: Tb was lower for early cultivars (TB and GB = 2.2°C; CH = 2.1°C; SM = 4.4°C; GK = 4.3°C) and higher for late cultivars (ER = 6.3°C; LE = 6.2°C; CS = 4.3°C; HA and PA = 8.2°C) for all cultures. The Tb f fruit cultivars related directly with genotype chilling requirements: the higher the chilling requirement, the higher the Tb of the cultivar. Cultivars of the same fruit species yielded a sum of degree-days almost equal to finalize the growing season, regardless of the degree of precocity (TB = 1720; ER = 1801; GB = 1680; LE = 1718; CH = 2310; CS = 2369; SM = 2096; PA = 2003 GD; GK = 2775; HA = 2691). Regarding phenological phases, 82% of the assessed cases responded more to thermal time (degree-days) than to chronological time (d) to complete phenological steps. Differences in Tb between genotypes are a relevant factor for improving the accuracy and applicability of phenology models in agriculture.

Effects of thermal model and base temperature on estimates of thermal time to bud break in white spruce seedlings

2010 ◽  
Vol 40 (9) ◽  
pp. 1815-1820 ◽  
Author(s):  
Rongzhou Man ◽  
Pengxin Lu
Keyword(s):  
White Spruce ◽  
Climatic Conditions ◽  
Thermal Time ◽  
Growing Degree Days ◽  
Base Temperature ◽  
Bud Break ◽  
Bud Burst ◽  
Degree Days ◽  
Growing Degree Hours ◽  
Time Requirements

To improve the predictability of bud burst and growth of boreal trees under varying climate, the thermal time for bud break in white spruce ( Picea glauca (Moench) Voss) seedlings was evaluated under a range of temperature conditions in controlled environment chambers. Thermal time requirements were calculated as the sum of growing degree days or growing degree hours above base temperatures ranging from –1 to 5 °C. The results indicated that the common modeling approach, which uses a high base temperature of 5 °C and growing degree days, may not be appropriate for future climatic conditions. Estimates of thermal time requirements using a base temperature of 5 °C varied considerably among temperature treatments and thus would reduce the predictability of bud burst under changing climate. In contrast, estimates of thermal time requirements with lower temperatures closer to 1 °C were relatively consistent among treatments. Growing degree hour models were less sensitive to base temperature than degree day models. These results should help in the selection of appropriate base temperatures and thermal time models in quantification of thermal time for bud burst modeling in other boreal trees.

scholarly journals A Degree-Day Model for the Latent Period of Stagonospora nodorum Blotch in Winter Wheat

Plant Disease ◽  
2011 ◽  
Vol 95 (5) ◽  
pp. 561-567 ◽  
Author(s):  
A. D. Zearfoss ◽  
C. Cowger ◽  
P. S. Ojiambo
Keyword(s):  
Winter Wheat ◽  
Latent Period ◽  
Linear Model ◽  
Thermal Time ◽  
Stagonospora Nodorum ◽  
Base Temperature ◽  
Degree Days ◽  
Stagonospora Nodorum Blotch ◽  
Mean Temperature ◽  
The Relationship

Stagonospora nodorum blotch (SNB), which is caused by Stagonospora nodorum, occurs frequently in the southeastern United States, and severe epidemics can lead to substantial yield losses. To develop a model for the progress of SNB based on the effects of temperature on the latent period of the pathogen, batches of two winter wheat cultivars, AGS 2000 and USG 3209, were inoculated with S. nodorum at weekly intervals for 16 weeks. After 72 h of incubation, inoculated plants were exposed to outdoor conditions where temperatures ranged from –6.6 to 35.8°C, with a mean batch temperature ranging from 9.7 to 24.7°C. Latent period, expressed as time from inoculation until the first visible lesions with pycnidia, ranged from 13 to 34 days. The relationship between the inverse of the latent period and mean temperature was best described by a linear model, and the estimated thermal time required for the completion of the latent period was 384.6 degree-days. A shifted cumulative gamma distribution model with a base temperature of 0.5°C significantly (P < 0.0001) described the relationship between increasing number of lesions with pycnidia and accumulated thermal time. When latent period was defined as time to 50% of the maximum number of lesions with pycnidia (L50), the model estimated L50 as 336 and 326 degree-days above 0.5°C for AGS 2000 and USG 3209, respectively. The relationship between 1/L50 and mean temperature was also best described using a linear model (r2 = 0.93, P < 0.001). This study provides data that link disease progress with wheat growth, which facilitates accurate identification of thresholds for timing of fungicide applications.

Thermal time model ofSolanum sarrachoidesgermination

2014 ◽  
Vol 24 (4) ◽  
pp. 321-330 ◽  
Author(s):  
J.P. del Monte ◽  
P.L. Aguado ◽  
A.M. Tarquis
Keyword(s):  
Thermal Model ◽  
Population Based ◽  
Thermal Time ◽  
Growing Degree Days ◽  
Base Temperature ◽  
Degree Days ◽  
Time Model ◽  
Physiological Dormancy ◽  
Thermal Time Model ◽  
Modelling Approach

AbstractA population-based modelling approach was used to predict the occurrence of germination inSolanum sarrachoides(SOLSA) for different treatments. Seeds collected in Toledo (Spain) were exposed to constant temperatures, to temperatures alternating between 10 and 30°C and to gibberellins (GAs; 0, 50, 100, 150 and 1000 ppm) during a 24-h imbibition period. The following parameters were measured: base temperature (Tb), mean thermal time (θT(50)) and the standard deviation of thermal time (σθT). The SOLSA seeds only germinated at constant temperatures when the highest GA concentration was applied. The thermal model suggests that the induction and loss of physiological dormancy following seed dispersal is achieved when temperatures vary and when a mean thermal time of 66 growing degree-days (d°C) and aTbvalue of 16°C are achieved when no GA treatment was added. The concentration of GA applied under conditions of alternating temperatures has an additive effect, reducing θT(50) up to threefold, from basal level (66 d°C) to 19.40 d°C, when the 1000 ppm GA treatment was applied. In this last case, the germination was accelerated by reducingTbto 14°C. A 5–10°C change in temperature and a range of average temperatures of 20–27.5°C promoted the germination of SOLSA seeds to the greatest extent in the absence of GA. However, these conditions are not frequently encountered in the irrigated areas of the studied region; this finding could explain the limited ability of SOLSA to expand its range within this area.

scholarly journals Initial growth and development of southern sandbur based on thermal units

2014 ◽  
Vol 32 (2) ◽  
pp. 335-343 ◽  
Author(s):  
E.C.R. Machado ◽  
R.S.O. Lima ◽  
A.P.P. Silva ◽  
B.S. Marques ◽  
M.F. Gonçalves ◽  
...  
Keyword(s):  
Growth And Development ◽  
Dry Matter ◽  
Integrated Management ◽  
Base Temperature ◽  
Initial Growth ◽  
Agricultural Systems ◽  
Degree Days ◽  
Flowering Stage ◽  
Weed Biology ◽  
Best Fit

Availability of basic information on weed biology is an essential tool for designing integrated management programs for agricultural systems. Thus, this study was carried out in order to calculate the base temperature (Tb) of southern sandbur (Cenchrus echinatus), as well as fit the initial growth and development of the species to accumulated thermal units (growing degree days - GDD). For that purpose, experimental populations were sown six times in summer/autumn conditions (decreasing photoperiod) and six times in winter/spring condition (increasing photoperiod). Southern sandbur phenological evaluations were carried out, on alternate days, and total dry matter was measured when plants reached the flowering stage. All the growth and development fits were performed based on thermal units by assessing five base temperatures, as well as the absence of it. Southern sandbur development was best fit with Tb = 12 ºC, with equation y = 0,0993x, where y is the scale of phenological stage and x is the GDD. On average, flowering was reached at 518 GDD. Southern sandbur phenology may be predicted by using mathematical models based on accumulated thermal units, adopting Tb = 12 ºC. However, other environmental variables may also interfere with species development, particularly photoperiod.

scholarly journals Basal temperature and thermal sum in phenological phases of nectarine and peach cultivars

2011 ◽  
Vol 46 (12) ◽  
pp. 1588-1596 ◽  
Author(s):  
Adilson Pacheco de Souza ◽  
Sarita Leonel ◽  
Andréa Carvalho da Silva
Keyword(s):  
Degree Days ◽  
Phenological Stages ◽  
Phase Duration ◽  
Open Flower ◽  
Thermal Sum ◽  
Phenological Phases

The objective of this work was to evaluate basal temperature, thermal sum at different phenological stages, phenological phase duration, yield and seasonality of one nectarine and 14 peach cultivars, between 2006 and 2009. The considered phenological phases were: pruning-sprouting; sprouting-flowering, from swollen bud to open flower; flowering-fruiting, from petal fall to medium-sized fruit; and ripening. Minimum basal temperatures (Tb) obtained were: pruning-sprouting, 8°C, irrespective of the cultivars; sprouting-flowering, 10°C, except for 'Cascata 968', which required 8°C Tb; flowering-fruiting, 12°C, except for 'Oro Azteca', which required 14°C Tb; ripening, 14°C, except for 'Sunblaze', 'Diamante Mejorado' and 'Precocinho' with 12°C Tb. For most cultivars, the maximum basal temperatures were 30, 34, 34 and 28ºC for phases pruning-sprouting, sprouting-flowering, flowering-fruiting and ripening, respectively. 'Turmalina', 'Marli' and 'Tropic Beauty' showed average yields of 3,945.0, 3,969.3 and 3,954.0 kg ha-1, respectively, in 2009, while the nectarine 'Sunblaze' showed around 3,900 kg ha-1 in 2008 and 2009. The cultivars differed for their total cycle and for the accumulated thermal sums which varied, respectively, from 245 days and 1,881.4 degree-days for 'Oro Azteca', to144 days and 1,455.7 degree-days for 'Precocinho'.

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