Studies on Determination of Critical Growing Degree Days, Base Temperature (Tb) and Response of Temperature Variations on Flowering and Yield per se in Cowpea [Vigna unguiculata (L.) Walp.]

2020 ◽  
Author(s):  
Venkatesh Bondade ◽  
Sanjeev K Deshpande
Keyword(s):  
Dry Matter ◽  
Significant Negative Correlation ◽  
Growing Degree Days ◽  
Base Temperature ◽  
Degree Days ◽  
Temperature Variations ◽  
Days To Flowering ◽  
Matter Production ◽  
Flowering Initiation

Growing degree days (GDD) or heat units accumulation is the major factor that affects the dry matter production in the plants. In the present investigation eleven genotypes were used to screen for temperature insensitivity through staggered plantings across the seasons in a year. Days to flowering initiation was recorded and base temperature (Tb) was determined using mean daily air temperature (MAT). GDD of individual genotypes was estimated using base temperatures of particular genotypes. It was observed that the GDD, days to flowering initiation and yield were exhibited high variation across the seasons, the flowering time from days to planting (FTDAP) registered significant negative correlation with GDD and MAT and positively correlated with yield. Whereas GDD is positively correlated with MAT and negatively correlated with yield. Here three genotypes namely, IC202926, IC198326 and IC257428 were identified as temperature insensitive genotypes as their performances were comparable across the seasons without much fluctuations.

scholarly journals Growth and Development of Purple Nutsedge Based on Days or Thermal Units

2015 ◽  
Vol 33 (2) ◽  
pp. 165-173 ◽  
Author(s):  
R.S.O. Lima ◽  
E.C.R. Machado ◽  
A.P.P. Silva ◽  
B.S. Marques ◽  
M.F. Gonçalves ◽  
...  
Keyword(s):  
Plant Growth ◽  
Mathematical Models ◽  
Growth And Development ◽  
Dry Matter ◽  
Cyperus Rotundus ◽  
Growing Degree Days ◽  
Plant Growth And Development ◽  
Degree Days ◽  
Purple Nutsedge ◽  
Independent Trials

This work was carried out with the objective of elaborating mathematical models to predict growth and development of purple nutsedge (Cyperus rotundus) based on days or accumulated thermal units (growing degree days). Thus, two independent trials were developed, the first with a decreasing photoperiod (March to July) and the second with an increasing photoperiod (August to November). In each trial, ten assessments of plant growth and development were performed, quantifying total dry matter and the species phenology. After that, phenology was fit to first degree equations, considering individual trials or their grouping. In the same way, the total dry matter was fit to logistic-type models. In all regressions four temporal scales possibilities were assessed for the x axis: accumulated days or growing degree days (GDD) with base temperatures (Tb) of 10, 12 and 15 oC. For both photoperiod conditions, growth and development of purple nutsedge were adequately fit to prediction mathematical models based on accumulated thermal units, highlighting Tb = 12 oC. Considering GDD calculated with Tb = 12 oC, purple nutsedge phenology may be predicted by y = 0.113x, while species growth may be predicted by y = 37.678/(1+(x/509.353)-7.047).

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 Phenology, reproductive biology and growing degree days of the grapevine ‘Isabel’ (Vitis labrusca, Vitaceae) cultivated in northeastern Brazil

2016 ◽  
Vol 76 (4) ◽  
pp. 975-982 ◽  
Author(s):  
N. A. S. Nunes ◽  
A. V. Leite ◽  
C. C. Castro
Keyword(s):  
Reproductive Biology ◽  
Pollen Viability ◽  
Floral Biology ◽  
Climatic Conditions ◽  
Northeastern Brazil ◽  
Growing Degree Days ◽  
Base Temperature ◽  
Vitis Labrusca ◽  
Degree Days ◽  
Inflorescence Development

Abstract Phenology and reproductive biology of cultivated species are important for the comprehension of the requirements for fruit and seed production and the management of pollinators. This study aimed to characterise the phenology, reproductive biology and growing degree days of the grapevine ‘Isabel’ (Vitis labrusca) in northeastern Brazil during January 2011 (P1), Augst 2011 (P2), April 2012 (P3) and August 2012 (P4). We recorded the duration (days) of the phenological stages, pruning (P), woolly bud (W), budburst (B), inflorescence development (ID), flowering (F), ripening (R) and harvest (H). We analysed the floral biology, the sexual system and the breeding system. We measured the growing degree days (GDD) required to reach the subperiods P-B, B-F and F-H. The periods P1, P2, P3 and P4 lasted for 116, 125, 117 and 130 days, respectively. The number of days of harvest were similar in the same dry (P1 and P3) and rainy (P2 and P4) periods. All the periods that we recorded were shorter than those observed in other regions of Brazil, which may be attributable to the mean temperature and carbohydrate metabolism. The flowers are green, hermaphroditic, with an odour of mignonette, low pollen viability and autogamous. The base temperature of 10°C was considered the most adequate for the subperiods as has been documented for other grape varieties in Brazil. Thus, temperature was also the most adequate for the cycles, presenting a smaller standard deviation (0.119, 0.147, 0.156 and 0.153 to P1, P2, P3 and P4, respectively) when compared to a base temperature of 12°C (0.122, 0.158, 0.165 and 0.160 to P1, P2, P3 and P4, respectively). The higher and the lower observed GDD were 1972.17 and 1870.05, respectively, both above the values recorded in other parts of Brazil for same variety. The phonological results, including knowledge of growing degree days, are important to the planning of cultures at the study site and in other regions that have similar climatic conditions and make it possible to pre-determine the harvest.

scholarly journals Spatial Soil Temperature and Moisture Monitoring Across the Transylvanian Plain in Romania

2010 ◽  
Vol 67 (1) ◽  
Author(s):  
Beatrix HAGGARD ◽  
Teodor RUSU ◽  
David WEINDORF ◽  
Horea CACOVEAN ◽  
Paula MORARU ◽  
...  
Keyword(s):  
Best Management Practices ◽  
Management Practices ◽  
Spline Interpolation ◽  
Planting Date ◽  
Growing Degree Days ◽  
Base Temperature ◽  
Degree Days ◽  
Corn Hybrids ◽  
Important Region ◽  
Soil Temperatures

The Transylvanian Plain, Romania is an important region for agronomic productivity. However, limited soils data and adoption of best management practices hinder land productivity. Soil temperatures of the Transylvanian Plain were evaluated using a set of twenty datalogging stations positioned throughout the plain. Soil temperatures were monitored at the surface and at 10, 30, and 50 cm depths, and soil moisture was monitored at 10 cm. Preliminary results indicate that most soils of the Transylvanian Plain will have a mesic temperature regime. However, differences in seasonal warming and cooling trends across the plain were noted. These have important implications for planting recommendations. Growing degree days (GDDs) are preferred over maturity ratings, because they can account for temperature anomalies. The crop being considered for this study was corn. The base temperature (BT) was set at 10oC, and the upper threshold was 30oC. Two methods were used to calculate GDDs; 1) minimum and maximum daily temperatures, and 2) 24 h of averaged temperature data. Growing degree days were run from 110-199 day of year (DOY) to represent approximate planting date to tasseling. The DOY that 694 accumulated growing degree days (AGDDs) was reached at each site was then analyzed to identify differences across the TP. Three sites failed to reach 694 AGDDs by DOY 199, and were excluded from comparisons to other results. Averaged values were used to create spline interpolation maps with ArcMap 9.2 (ESRI, Redlands, CA, USA). The southeastern portion of the TP was found to tassel a month earlier assuming a planting date of 109 DOY. Four DeKalb® corn hybrids were then selected based on GDDs to tasseling, drydown, drought tolerance, and insect resistance. With a better understanding of the GDD trends across the TP, more effective planting and harvesting could be accomplished by Romanian farmers to maximize agronomic production.

INFLUENCE OF PHOTOPERIOD AND WATER STRESS ON GROWTH, YIELD AND DEVELOPMENT RATE OF BARLEY MEASURED IN HEAT UNITS

1987 ◽  
Vol 67 (1) ◽  
pp. 21-34 ◽  
Author(s):  
L. M. DWYER ◽  
D. W. STEWART
Keyword(s):  
Water Stress ◽  
Leaf Area ◽  
Dry Matter ◽  
Growth Yield ◽  
Development Rate ◽  
Degree Days ◽  
Heat Units ◽  
Matter Production ◽  
Stress Maximum ◽  
Significant Yield

Barley (Hordeum vulgare ’Bruce’) was grown in a greenhouse under three photoperiods (8, 12 and 16 h) and nine watering treatments, resulting in different timing, duration and intensity of water stress. Phenological development, according to the Feekes scale, was monitored three times a week and leaf area was measured weekly from tillering to ripening. Final aboveground and root dry matter production and grain yield were obtained at harvest. Phenological observations were fit to a nonlinear photothermal model that expressed phenological development as a function of heat units modified by photoperiod. In the absence of water stress, maximum leaf area was directly proportional to photoperiod and the time of maximum leaf area was delayed at longer photoperiods. Water stress hastened leaf area senescence and, in general, the more severe the stress, the greater the reduction in leaf area. Most stress treatments also resulted in lower shoot/root ratios than found in well-watered controls, as well as significant yield reductions. Reduction in biomass and yield components appeared independent of photoperiod. In contrast, not only was phenological development rate proportional to photoperiod, but the effect of water stress on development rate was modified by photoperiod. Development was significantly delayed by several water stress treatments; no treatment significantly hastened development. A stress period from tillering to the beginning of stem extension caused the largest, and most consistent, delay and the duration of the delay was inversely proportional to the photoperiod.Key words: Barley, degree days, phenology, leaf area, biomass

Growth, phenology and thermal indices of mungbean as influenced by sowing time, varieties and planting geometry

2015 ◽  
Vol 49 (5) ◽  
Author(s):  
Harinder Singh ◽  
Guriqbal Singh
Keyword(s):  
Field Experiment ◽  
Dry Matter ◽  
Growing Degree Days ◽  
Dry Matter Accumulation ◽  
Degree Days ◽  
Thermal Indices ◽  
Higher Plant ◽  
Phenological Stages ◽  
Sowing Time ◽  
Planting Geometry

A field experiment was conducted during <italic>kharif</italic> 2012 to assess the effects of sowing time (1, 10, 20, and 30 July) and planting geometry (30 cm × 10 cm and 22.5 cm × 10 cm) on the growth, phenology and thermal indices of mungbean varieties (PAU 911 and ML 818). The crop sown on 1 July recorded higher plant height and dry matter accumulation (DMA) and required higher thermal indices <italic>viz</italic>. accumulated growing degree days (AGDD), accumulated photothermal units (APTU) and accumulated heliothermal units (AHTU) to complete various phenological stages as compared to all other sowing times. Mungbean variety PAU 911 took lesser days to complete various phenological stages and required lesser AGDD, AHTU and APTU as compared to ML 818. Plants in planting geometry of 30 cm ×10 cm recorded significantly higher DMA and attained significantly higher AGDD, AHTU and APTU as compared to in 22.5 cm ×10 cm geometry.

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