The influence of plant raising conditions and transplant age on the growth and development of crisp lettuce

1987 ◽  
Vol 109 (3) ◽  
pp. 573-581 ◽  
Author(s):  
D. C. E. Wurr ◽  
Jane R. Fellows ◽  
Angela J. Pittam
Keyword(s):  
Solar Radiation ◽  
Growth And Development ◽  
Total Solar Radiation ◽  
Ambient Temperatures ◽  
Light Levels ◽  
Head Weight ◽  
Selection For ◽  
Positive Correlations ◽  
Crop Maturity ◽  
Different Levels

SummaryThe influences of the temperature during plant raising and the age of plants at transplanting on the time of hearting and head weight at maturity of the crisp lettuce variety Saladin R100 were determined in seven experiments between 1984 and 1986.Plants raised at ambient temperatures and transplanted before the end of May produced heads which were heavier and matured later than those from plants raised at higher temperatures under glass. The influence of transplant age on head weight was much smaller than that of raising conditions and there were inconsistent effects on the time of crop maturity. When the head weights at maturity of all treatments were considered there were highly significant positive correlations with total solar radiation in the periods 7 and 10 days before 50% hearting occurred. Further examination of this effect revealed that heads heavier than 800 g were strongly associated with mean daily solar radiation exceeding 15MJ/m2 in the periods 7 and 14 days before 50% hearting. This suggests that breeding for stability of head weight from crop to crop is likely to be aided by selection for consistency of head weight under a range of light levels in the prehearting phase.The coefficient of variation of the period from transplanting to maturity, measured in terms of various environmental characters, was lowest using effective day-degrees, which take account of different levels of solar radiation at the same mean temperature. This suggests that effective day-degrees may be the best indicator of the duration of crop growth and therefore of benefit in developing techniques to predict the time of crop maturity.

scholarly journals Effects of solar radiation and relative humidity on germination of Botryosphaeriaceae species conidia

2010 ◽  
Vol 63 ◽  
pp. 28-32 ◽  
Author(s):  
N.T. Amponsah ◽  
E.E. Jones ◽  
H.J. Ridgway ◽  
M.V. Jaspers
Keyword(s):  
Relative Humidity ◽  
Solar Radiation ◽  
Light Levels ◽  
Moist Environment ◽  
Different Levels ◽  
Botryosphaeriaceae Species

Viability and germination of conidia of three Botryosphaeriaceae species which are important grapevine pathogens were significantly affected by exposure to different levels of sunlight and relative humidity (RH) After 7 h exposure to nonfiltered sunlight (UV) filtered sunlight (UV) and shade germination differed between light levels being 35 57 and 81 respectively and after 70 h exposure it was 0 21 and 65 respectively Nongerminated conidia were unable to germinate when placed in a moist environment indicating that they had been killed High RH favoured germination since 91 and 70 respectively germinated after 3 h in 100 and 97 RH However in 93 RH only 44 germinated by 24 h and in 84 RH no conidia germinated The inhibition of germination was temporary since replacement in a moist environment caused conidia to germinate Light and RH effects were similar for the three species

scholarly journals Trees as a solar control measure for southern-oriented street frontages. Analysis of a selected street model for a humid continental climate

2021 ◽  
Author(s):  
Katarzyna Zielonko-Jung ◽  
Justyna Janiak
Keyword(s):  
Numerical Simulation ◽  
Solar Radiation ◽  
Control Measure ◽  
Total Solar Radiation ◽  
Single Row ◽  
Ground Floor ◽  
Radical Reduction ◽  
Solar Control ◽  
Sycamore Maple ◽  
Continental Climate

AbstractThe present study is aimed at the analysis of possibilities for shading southern frontage of street oriented along the E-W axis by the single row of trees, parallel to the southern elevations. The effectiveness of solar control shading was tested depending on the geometric relationships between trees and buildings. Numerical simulation analyses were conducted in Rhinoceros® program for the street located in humid continental climate in city Płock, Poland (52°32′50 “N 19°42’00 “E), for the day of the highest degree of total solar radiation in the year i.e. June 7th, during hours: 8.00a.m - 5.00 p.m. The analysis has proved that a row of 20–25 year old Sycamore Maple ‘Rotterdam’ in the street 30 m wide and 18 m high (H/W = 0.6), can provide solar protection for the southern frontage, especially when trees are located no more than 4 m away. Location of greenery within the range of 4 to 5 m from the buildings leads to a radical reduction in the possibility of shading the wall surfaces (at 5 m to 0%). Over 90% of the shading area of the ground floor façade walls was found when trees were within the distance 2 and 3 m away from the building.

Estimation of the total solar radiation from meteorological data

Solar Energy ◽  
1977 ◽  
Vol 19 (3) ◽  
pp. 307-311 ◽  
Author(s):  
J.A. Sabbagh ◽  
A.A.M. Sayigh ◽  
E.M.A. El-Salam
Keyword(s):  
Solar Radiation ◽  
Meteorological Data ◽  
Total Solar Radiation

A Perturbation Method Based on Singular Value Decomposition and Feature Selection for Privacy Preserving Data Mining

2014 ◽  
Vol 10 (1) ◽  
pp. 55-76 ◽  
Author(s):  
Mohammad Reza Keyvanpour ◽  
Somayyeh Seifi Moradi
Keyword(s):  
Data Mining ◽  
Feature Selection ◽  
Singular Value Decomposition ◽  
Perturbation Method ◽  
Privacy Preserving ◽  
Singular Value ◽  
Privacy Preserving Data Mining ◽  
Selection For ◽  
Value Decomposition ◽  
Different Levels

In this study, a new model is provided for customized privacy in privacy preserving data mining in which the data owners define different levels for privacy for different features. Additionally, in order to improve perturbation methods, a method combined of singular value decomposition (SVD) and feature selection methods is defined so as to benefit from the advantages of both domains. Also, to assess the amount of distortion created by the proposed perturbation method, new distortion criteria are defined in which the amount of created distortion in the process of feature selection is considered based on the value of privacy in each feature. Different tests and results analysis show that offered method based on this model compared to previous approaches, caused the improved privacy, accuracy of mining results and efficiency of privacy preserving data mining systems.

scholarly journals Protective Netting Improves Leaf-level Photosynthetic Light Use Efficiency in ‘Honeycrisp’ Apple Under Heat Stress

HortScience ◽  
2018 ◽  
Vol 53 (10) ◽  
pp. 1416-1422 ◽  
Author(s):  
Giverson Mupambi ◽  
Stefano Musacchi ◽  
Sara Serra ◽  
Lee A. Kalcsits ◽  
Desmond R. Layne ◽  
...  
Keyword(s):  
Heat Stress ◽  
Solar Radiation ◽  
Leaf Gas Exchange ◽  
Growing Season ◽  
High Light ◽  
Weather Data ◽  
Light Use Efficiency ◽  
Ambient Temperatures ◽  
Leaf Level ◽  
Use Efficiency

Globally, apple production often occurs in semiarid climates characterized by high summer temperatures and solar radiation. Heat stress events occur regularly during the growing season in these regions. For example, in the semiarid eastern half of Washington State, historic weather data show that, on average, 33% of the days during the growing season exceed 30 °C. To mediate some of the effects of heat stress, protective netting (PN) can be used to reduce the occurrence of fruit sunburn. However, the impacts of reduced solar radiation in a high light environment on light-use efficiency and photosynthesis are poorly understood. We sought to understand the ecophysiological response of apple (Malus domestica Borkh. cv. Honeycrisp) under blue photoselective PN during days with low (26.6 °C), moderate (33.7 °C), or high (38.1 °C) ambient temperatures. Two treatments were evaluated; an uncovered control and blue photoselective PN. Maximum photochemical efficiency of PSII, or photosystem II (Fv/Fm) was significantly greater at all measurement times under blue photoselective PN compared with the control on days with high ambient temperatures. Fv/Fm dropped below 0.79, which is considered the threshold for stress, at 1000 hr in the control and at 1200 hr under blue photoselective PN on a day with high ambient temperature. On days with low or moderate ambient temperatures, Fv/Fm was significantly greater under blue photoselective PN at 1400 hr, which coincided with the peak in solar radiation. ‘Honeycrisp’ apple exhibited dynamic photoinhibition as shown by the diurnal decline in Fv/Fm. Quantum photosynthetic yield of PSII (ΦPSII) was also generally greater under blue photoselective PN compared with the control for days with moderate or high ambient temperatures. Photochemical reflectance index (ΔPRI), the difference in reflectance between a stress-responsive and nonstress-responsive wavelength, was greater under PN compared with the control on the day with high ambient temperatures, with no differences observed under low or moderate ambient temperatures. Leaf gas exchange did not show noticeable improvement under blue photoselective netting when compared with the control despite the improvement in leaf-level photosynthetic light use efficiency. In conclusion, PN reduced incoming solar radiation, improved leaf-level photosynthetic light use efficiency, and reduced the symptoms of photoinhibition in a high-light, arid environment.

scholarly journals Variance components and correlations of agronomic traits among cabbage (Brassica oleracea var. capitata L.) maturity groups

Genetika ◽  
2012 ◽  
Vol 44 (1) ◽  
pp. 55-68 ◽  
Author(s):  
Janko Cervenski ◽  
Jelica Gvozdanovic-Varga ◽  
Svetlana Glogovac
Keyword(s):  
Plant Height ◽  
Correlation Coefficients ◽  
Early Spring ◽  
F1 Hybrids ◽  
Plant Weight ◽  
Whole Plant ◽  
Head Weight ◽  
Positive Correlations ◽  
Head Height ◽  
Maturity Groups

In this paper we studied the variability and correlation of cabbage traits in different maturity groups. The study included early spring cabbages (planted in early spring, harvested in early summer) and autumn cabbages (planted in mid-summer, harvested in late autumn). Using coefficients of variation and correlation coefficients, we analyzed 17 cabbage traits in 35 commercially grown cultivars, F1 hybrids, and experimental F1 hybrids. The traits were analyzed separately for each maturity group. In the early cabbages, the coefficients of variation ranged from 4.8 to 44.2%. The calculated correlation coefficients differed between the two maturity groups. The early cabbages had 26 significant positive correlations. The positive correlations calculated among different traits of early cabbages defined this group fully and made it distinct from the late-maturing genotypes. Plant height and rosette diameter in the early genotypes were highly positively correlated with rosette weight, whole plant weight, head weight, usable portion of head, head height, and head diameter. Plant height and rosette diameter participate in the formation of active photosynthetic area in early cabbages. Rosette width in these genotypes provides a greater influx of light and heat, which results in greater head weight. Also, in early cabbages that have greater plant height, the leaf rosette will not lie on the cold surface of the ground in the spring. The activity of the cabbage plant is thus more focused towards the formation of larger head weight. Head volume in the late genotypes was highly positively correlated with rosette diameter, whole plant weight, head weight, usable portion of head, inner stem length, and head height. In late cabbages plant activity is directed towards the formation of head volume due to the longer duration of the growth period, larger leaves, and differences in climatic conditions.

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