Allometric relationships for vegetative growth flush in pruned stems of macadamia (Macadamia integrifolia): effects of carbohydrate source and season

2017 ◽  
Vol 68 (8) ◽  
pp. 760
Author(s):  
S. Karimaei ◽  
D. Doley ◽  
J. Hanan
Keyword(s):  
Shoot Growth ◽  
Fruit Production ◽  
Growing Degree Days ◽  
Allometric Relationships ◽  
Degree Days ◽  
Carbohydrate Source ◽  
Shoot Morphology ◽  
Macadamia Integrifolia ◽  
Number Of Leaves ◽  
Control Tree

Hedging is used to control tree size in macadamia orchards, but the effects on subsequent shoot growth and floral initiation may impair fruit production. Four-year-old grafted macadamia (Macadamia integrifolia Maiden & Betche) trees were subjected to pruning of the most recent seasonal shoot in autumn and spring. Factorial combinations of treatments included girdling or not girdling near the base of the previous season’s (parent) shoot; removal of all except two, four or six leaves from the parent shoot; and defoliation or no defoliation of the shoot that appeared after pruning. Initial numbers and dimensions of flush-shoot internodes were similar for all branch treatments in autumn and for girdled branches in spring, and were smaller than half those for non-girdled stems in spring. Later flush-shoot growth depended on the number of leaves retained on the parent shoot, the presence or absence of a connection to the tree below the parent shoot, and on the season, declining with limiting growing degree-days in winter and accelerating with increasing growing degree-days in summer. In both seasons, reserves beyond the parent (previous season’s) shoot contributed the major source of carbohydrate for continuing flush-shoot growth, and particularly the growth of leaves. The combinations of seasonal conditions, shoot parameters before the commencement of flush-shoot growth, and flush-shoot morphology permit the inference of allometric relationships that can be applied to the quantitative modelling of vegetative shoot morphology and growth in macadamia.

Timing and rate of bud formation in Pinus resinosa

1971 ◽  
Vol 49 (10) ◽  
pp. 1821-1832 ◽  
Author(s):  
Edward Sucoff
Keyword(s):  
Quantitative Data ◽  
Shoot Growth ◽  
Pinus Resinosa ◽  
Growing Season ◽  
Axillary Buds ◽  
Growing Degree Days ◽  
Degree Days ◽  
Bud Formation ◽  
Late Season ◽  
Apical Dome

During the 1969 and 1970 growing season buds were collected almost weekly from matched trees in northeastern Minnesota. Cataphyll primordia for the year n + 1 shoot began forming at the time that internodes in the year n shoot started elongating (late April) and continued forming until early September. Primordia for axillary buds started forming about 2 months later and stopped forming at the same time as cataphylls. The size and deposition activity of the apical dome simultaneously increased during the early growing season and decreased during the late season. The maximum rates in July were over nine cataphylls per day.Rate of cataphyll deposition paralleled elongation of the needles on subtending shoots. Forty to fifty percent of the cataphylls had been formed when shoot growth was 95% complete. Although the bulk of the depositions occurred earlier in 1970, when growing degree days were used as the clock, the 2 years were similar.The results provide quantitative data to complement the histologic emphasis of previous studies.

scholarly journals MODELING THE OCCURRENCE OF THE FLOWERING PEAK OF MACADAMIA NUT (MACADAMIA INTEGRIFOLIA)

HortScience ◽  
1992 ◽  
Vol 27 (12) ◽  
pp. 1262b-1262
Author(s):  
Sam-Gwang Hwang ◽  
Kent D. Kobayashi ◽  
Mike A. Nagao
Keyword(s):  
Minimum Temperature ◽  
Proper Time ◽  
Maximum Temperature ◽  
Total Solar Radiation ◽  
Growing Degree Days ◽  
Degree Days ◽  
Macadamia Integrifolia ◽  
Flowering Season ◽  
Macadamia Nut ◽  
Starting Date

The objective of this study was to develop models to predict the occurrence of the flowering peak of macadamia nut (Macadamia integrifolia). At Hilo and Kona, weather and `Ikaika' flowering data were collected. The best model that described the time from the starting date of the flowering season to the highest flowering peak was days = 249.15 + 0.12 (total growing degree days) - 5.81 (maximum temperature) - 6.26 (minimum temperature). The model predicted the highest peak 4 days before it occurred at Hilo and 4 days after it occurred at Kona. Two statistical models, one for each location, were developed to predict the time from the starting date of the flowering season to the first peak. At Hilo, the best model was days = 118.61 - 0.11 (total growing degree days) + 0.000168 (total solar radiation). The model predicted the first peak 1 day before it occurred in the field. The best model at Kona was days = (-156.34) + 12.67 (minimum temperature) + 0.01 (total growing degree days). The model predicted the first peak on the day it occurred in the field. These models may aid growers in predicting the flowering peak so that bees can be brought into orchards at the proper time to increase cross-pollination.

Leaf appearance rate of summer rape

1991 ◽  
Vol 71 (2) ◽  
pp. 405-412 ◽  
Author(s):  
M. J. Morrison ◽  
P. B. E. McVetty
Keyword(s):  
Leaf Number ◽  
Growing Degree Days ◽  
Linear Regression Equation ◽  
Degree Days ◽  
Mean Temperature ◽  
Appearance Rate ◽  
Leaf Appearance Rate ◽  
Number Of Leaves ◽  
Leaf Appearance ◽  
The Relationship

Leaf appearance rate (LAR) is defined as the slope of the regression of leaf number on time of appearance. LARs were calculated for summer rape using both calendar days (CD) and growing degree days (GDD) as measurements of time. The relationship between the number of leaves and GDD or CD was linear. LARs after emergence were 0.022 leaves GDD−1 or 0.247 leaves d−1. Summer rape was grown in growth cabinets set at different mean temperatures to study the effect of air temperature on LAR. The relationship between leaf number and time was linear. When CD were used as a measure of time, LAR increased as mean temperature increased, while the reverse was true when GDD were used to measure time. Cabinet and field LARs were compared at a field mean temperature of 16.5 °C. Cabinet LARs were 0.021 leaves GDD−1 or 0.22 leaves CD−1 which were similar to those calculated in the field. The linear regression equation describing the relationship between LAR (leaves GDD−1) and mean cabinet temperature was used with field-measured daily mean temperatures and GDD to predict the number of leaves for field conditions. When observed number of leaves were plotted against predicted number of leaves, the resulting slope was not significantly different from one, indicating that the model developed in the growth cabinet can be used to predict LAR in the field. Key words: Leaf appearance rate, Brassica napus, phyllochron

Evaluation of Finger Millet Varieties under Rainfed Condition of Eastern India

2017 ◽  
Vol 4 (03) ◽  
Author(s):  
M. K. Singh ◽  
VINOD KUMAR ◽  
SHAMBHU PRASAD
Keyword(s):  
Field Experiment ◽  
Finger Millet ◽  
Yield Potential ◽  
Growing Degree Days ◽  
Eastern India ◽  
Degree Days ◽  
Rainfed Condition ◽  
Net Returns ◽  
Humid Environment ◽  
Use Efficiency

A field experiment was carried out during the kharif of 2014 and 2015 to evaluate the yield potential, economics and thermal utilization in eleven finger millet varieties under the rainfed condition of the sub-humid environment of South Bihar of Eastern India. Results revealed that the significantly higher grain yield (20.41 q ha-1), net returns (Rs 25301) and B: C ratio (1.51) was with the finger millet variety ‘GPU 67’ but was being at par to ‘GPU28’and ‘RAU-8’, and significantly superior over remaining varieties. The highest heat units (1535.1oC day), helio-thermal units (7519.7oC day hours), phenothermal index (19.4 oC days day-1) were recorded with variety ‘GPU 67’ followed by ‘RAU 8’ and ‘GPU 28’ and lowest in ‘VL 149’ at 50 % anthesis stage. Similarly, the highest growing degree days (2100 oC day), helio-thermal units (11035.8 oC day hours) were noted with ‘GPU 67’ followed by ‘RAU 8’ and ‘GPU 28’ at maturity. The highest heat use efficiency (0.97 kg ha-1 oC day) and helio-thermal use efficiency (0.19 kg ha-1 oC day hour) were in ‘GPU 67’ followed by ‘VL 315’.

scholarly journals Determining the critical period for weed control in high-yielding cotton using common sunflower as a mimic weed

2019 ◽  
Vol 33 (6) ◽  
pp. 800-807 ◽  
Author(s):  
Graham W. Charles ◽  
Brian M. Sindel ◽  
Annette L. Cowie ◽  
Oliver G. G. Knox
Keyword(s):  
Weed Control ◽  
Critical Period ◽  
Yield Loss ◽  
Field Studies ◽  
Growing Degree Days ◽  
Degree Days ◽  
Weed Density ◽  
High Level ◽  
The Cost ◽  
Planting Season

AbstractField studies were conducted over six seasons to determine the critical period for weed control (CPWC) in high-yielding cotton, using common sunflower as a mimic weed. Common sunflower was planted with or after cotton emergence at densities of 1, 2, 5, 10, 20, and 50 plants m−2. Common sunflower was added and removed at approximately 0, 150, 300, 450, 600, 750, and 900 growing degree days (GDD) after planting. Season-long interference resulted in no harvestable cotton at densities of five or more common sunflower plants m−2. High levels of intraspecific and interspecific competition occurred at the highest weed densities, with increases in weed biomass and reductions in crop yield not proportional to the changes in weed density. Using a 5% yield-loss threshold, the CPWC extended from 43 to 615 GDD, and 20 to 1,512 GDD for one and 50 common sunflower plants m−2, respectively. These results highlight the high level of weed control required in high-yielding cotton to ensure crop losses do not exceed the cost of control.

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).

CHLOROGENIC ACID CONTENT OF SUNFLOWER SEED FLOUR AS AFFECTED BY SEEDING AND HARVEST DATE

1976 ◽  
Vol 56 (4) ◽  
pp. 901-905 ◽  
Author(s):  
D. G. DORRELL
Keyword(s):  
Chlorogenic Acid ◽  
Acid Content ◽  
Vegetative Growth ◽  
Sunflower Seed ◽  
Growing Season ◽  
Growing Degree Days ◽  
Degree Days ◽  
Normal Field ◽  
Seed Flour ◽  
Seeding Date

The effect of seeding date on the chlorogenic acid content of sunflower seed flour was determined by seeding the cultivars Krasnodarets and Peredovik at seven dates, starting on 14 May, over 3 yr. Sequential plantings were made at increments of approximately 70 growing degree days (base = 5.6 C). Plants were harvested at normal field maturity. The time and rate of deposition of chlorogenic acid was determined by harvesting plants at 7-day intervals from 21 to 49 days after flowering. The seeds were dehulled and defatted before determining the chlorogenic acid content of the flour. Chlorogenic acid content declined steadily from an average of 4.22% for the first seeding to 3.30% for the last seeding. About one-half of the total chlorogenic acid was present 21 days after flowering. Deposition continued rapidly for the next 14 days then the level began to stabilize. Delay in seeding tended to shorten the period of vegetative growth and shift the deposition of chlorogenic acid to a cooler portion of the growing season. It is suggested that a combination of these factors caused the reduction in chlorogenic acid content of sunflower flour.

scholarly journals Mid-Holocene climate change in Europe: a data-model comparison

2007 ◽  
Vol 3 (3) ◽  
pp. 499-512 ◽  
Author(s):  
S. Brewer ◽  
J. Guiot ◽  
F. Torre
Keyword(s):  
Climate Change ◽  
Data Model ◽  
General Circulation ◽  
Model Comparison ◽  
General Circulation Models ◽  
Growing Degree Days ◽  
Degree Days ◽  
European Continent ◽  
Holocene Climate Change ◽  
Correct Location

Abstract. We present here a comparison between the outputs of 25 General Circulation Models run for the mid-Holocene period (6 ka BP) with a set of palaeoclimate reconstructions based on over 400 fossil pollen sequences distributed across the European continent. Three climate parameters were available (moisture availability, temperature of the coldest month and growing degree days), which were grouped together using cluster analysis to provide regions of homogenous climate change. Each model was then investigated to see if it reproduced 1) similar patterns of change and 2) the correct location of these regions. A fuzzy logic distance was used to compare the output of the model with the data, which allowed uncertainties from both the model and data to be taken into account. The models were compared by the magnitude and direction of climate change within the region as well as the spatial pattern of these changes. The majority of the models are grouped together, suggesting that they are becoming more consistent. A test against a set of zero anomalies (no climate change) shows that, although the models are unable to reproduce the exact patterns of change, they all produce the correct signs of change observed for the mid-Holocene.

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