scholarly journals The Relationship Between Leaf Area and Light Interception by Spur and Extension Shoot Leaves and Apple Orchard Productivity

HortScience ◽  
2000 ◽  
Vol 35 (7) ◽  
pp. 1202-1206 ◽  
Author(s):  
Jens N. Wünsche ◽  
Alan N. Lakso
Keyword(s):  
Leaf Area ◽  
Production Systems ◽  
Light Interception ◽  
Apple Orchard ◽  
Fruit Yield ◽  
Area Index ◽  
Canopy Development ◽  
Slender Spindle ◽  
The Relationship ◽  
Canopy Light Interception

The study evaluated the relationship of spur vs. extension shoot leaf area and light interception to apple (Malus {XtimesX}domesticaBorkh.) orchard productivity. Fifteen-year-old `Marshall McIntosh'/M.9 trees had significantly greater leaf area and percentage of light interception at 3-5 and 10-12 weeks after full bloom (AFB) than did 4-year-old `Jonagold'/Mark trees. Despite significant increases in leaf area and light interception with canopy development, linear relationships between total, spur, and extension shoot canopy leaf area index (LAI) and 1) light interception and 2) fruit yield were similar at both times. Mean total and spur canopy LAI and light interception were significantly and positively correlated with fruit yield; however, extension shoot LAI and light interception were poorly correlated with yield. In another study total, spur and extension shoot canopy light interception varied widely in five apple production systems: 15-year-old central leader `Redchief Delicious' MM.111, 15-year-old central leader `Redchief Delicious' MM.111/M.9, 16-year-old slender spindle `Marshall McIntosh' M.9, 14-year-old `Jerseymac' M.9 on 4-wire trellis, and 17-year-old slender spindle `MacSpur' M.9. Yields in these orchards were curvilinearly related to total and extension shoot canopy light interception and decreased when total light interception exceeded 60% and extension shoot interception exceeded 25%. Fruit yields were linearly and highly correlated (r2 = 0.78) with spur light interception. The findings support the hypothesis that fruit yields of healthy apple orchards are better correlated with LAI and light interception by spurs than by extension shoots. The results emphasize the importance of open, well-illuminated, spur-rich tree canopies for high productivity.

CANOPY CHARACTERISTICS OF CONTRASTING CLONES OF CACAO (THEOBROMA CACAO)

2002 ◽  
Vol 38 (3) ◽  
pp. 359-367 ◽  
Author(s):  
A. J. Daymond ◽  
P. Hadley ◽  
R. C. R. Machado ◽  
E. Ng
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Theobroma Cacao ◽  
Light Interception ◽  
Canopy Architecture ◽  
Mature Trees ◽  
Area Index ◽  
Mean Values ◽  
Extinction Coefficients ◽  
The Relationship

Canopy characteristics (leaf area index, fractional light interception, extinction coefficient) of mature trees of ten clonally propagated cacao cultivars were measured over a period of 14 months at an experiment site in Bahia, Brazil. Differences in leaf area index between clones became more pronounced over time. When an approximately constant leaf area index was reached (after about nine months), the leaf area index varied between clones from 2.8 to 4.5. Clonal differences in the relationship between leaf area index and fractional light interception implied differences in canopy architecture, as reflected by the range of extinction coefficients (mean values ranged from 0.63 for the clone TSH-565 to 0.82 for CC-10). The results demonstrate the potential for breeding more photosynthetically efficient cacao canopies.

scholarly journals The Bases of Productivity in Apple Production Systems: The Role of Light Interception by Different Shoot Types

1996 ◽  
Vol 121 (5) ◽  
pp. 886-893 ◽  
Author(s):  
Jens N. Wünsche ◽  
Alan N. Lakso ◽  
Terence L Robinson ◽  
Fritz Lenz ◽  
Steven S. Denning
Keyword(s):  
Production Systems ◽  
Net Photosynthesis ◽  
Light Interception ◽  
Total Light ◽  
Slender Spindle ◽  
Apple Production ◽  
Fisheye Photographs ◽  
Role Of Light ◽  
Canopy Light Interception

Although apple (Malus domestica Borkh.) system yield differences are generally related to whole-canopy light interception, this study tested the hypothesis that these orchard yields are related primarily to total light intercepted by the spur canopy. Seasonal leaf area development of different shoot types, exposed bourse shoot leaf net photosynthesis, fruit growth, whole canopy light interception (by image analysis of fisheye photographs) and relative light interception by different shoot types (by a laser assisted canopy scanning device) were estimated within four 14-year-old `Empire' apple production systems (slender spindle/M.9, central leader/M.7, central leader/M.9/MM.111 and Y-trellis/M.26). The final LAI values were CL/M.7 = 1.8, CL/9/111 = 2.3, SS/M.9 = 2.6 and Y/M.26 = 3.6. Exposed leaf net photosynthesis showed few differences and was not dependent upon the production system. Yields of the pyramidal shaped tree forms were 40 to 42 t·ha-1 while Y-trellis produced 59 t·ha-1, with similar fruit sizes. Again, yields were primarily related to the percentage of light intercepted by the whole canopy, 48% to 53% for conic forms versus 62% for the Y-trellis system. Laser analyses showed that the Y-trellis system intercepted about 20% to 30% more light with the spur canopy than the conic tree forms, supporting the hypothesis. Yields were better correlated with spur canopy LAI and spur canopy light interception than with extension shoot canopy LAI and light interception.

Orchard training systems influence early canopy development and light microclimate within apple tree canopies

1993 ◽  
Vol 73 (1) ◽  
pp. 237-248 ◽  
Author(s):  
Frank Kappel ◽  
Harvey A. Quamme
Keyword(s):  
Leaf Area ◽  
Low Light ◽  
Area Index ◽  
Canopy Development ◽  
Training Systems ◽  
Light Levels ◽  
Tree Canopies ◽  
Slender Spindle ◽  
And Training ◽  
Radiation Measurements

Delicious and McIntosh apple trees were trained to five orchard systems: central leader (two spacings), slender spindle, van Roechoudt trellis, and vertical axe. Radiation measurements were taken at the bottom of the canopy throughout the season or at various heights within the canopy after the growth of the canopy was completed. Early in the life of the plantings slender spindle and vertical axe trees of each cultivar had the highest yields expressed on a per hectare basis. By the fifth year of the planting, McIntosh trees trained to the slender spindle and the narrow central leader spacing were producing similar amounts of fruit. Light levels at the bottom of the canopy for some orchard systems were at or below 30% of full sun as early as 25 d after petal fall. Orchard system affected total leaf area and the number of spurs per tree in both 1989 and 1990. The low light levels at the bottom of the canopy reported in this study suggest that attention to pruning and training in the early stages of the orchard development is critical. Key words: Malus domestica, central leader, slender spindle, van Roechoudt trellis, vertical axe, light distribution, leaf area index

scholarly journals Varying Density with Constant Rectangularity: I. Effects on Apple Tree Growth and Light Interception in Three Training Systems over Ten Years

HortScience ◽  
2004 ◽  
Vol 39 (3) ◽  
pp. 501-506 ◽  
Author(s):  
Cheryl R. Hampson ◽  
Harvey A. Quamme ◽  
Frank Kappel ◽  
Robert T. Brownlee
Keyword(s):  
Leaf Area ◽  
Tree Height ◽  
Light Interception ◽  
Training System ◽  
Influential Factor ◽  
Planting Density ◽  
Area Index ◽  
Training Systems ◽  
Slender Spindle ◽  
Plot Design

The effect of increasing planting density at constant rectangularity on the vegetative growth and light interception of apple [Malus ×sylvestris (L) var. domestica (Borkh.) Mansf.] trees in three training systems (slender spindle, tall spindle, and Geneva Y trellis) was assessed for 10 years. Five tree densities (from 1125 to 3226 trees/ha) and two cultivars (Royal Gala and Summerland McIntosh) were tested in a fully guarded split-split plot design. Planting density was the most influential factor. As tree density increased, tree size decreased, and leaf area index and light interception increased. A planting density between 1800 and 2200 trees/ha (depending on training system) was needed to achieve at least 50% light interception under the conditions of this trial. Training system altered tree height and canopy diameter, but not total scion weight. Training system began to influence light interception in the sixth leaf, when the Y trellis system intercepted more light than either spindle form. Trees trained to the Y trellis tended to have more spurs and a lower proportion of total leaf area in shoot leaves than the other two systems. The slender and tall spindles were similar in most aspects of performance. Tall spindles did not intercept more light than slender spindles. `Royal Gala' and `Summerland McIntosh' trees intercepted about the same amount of light. `Royal Gala' had greater spur leaf area per tree than `Summerland McIntosh', but the cultivars were similar in shoot leaf area per tree and spur density.

On the relationship of NDVI with leaf area index in a deciduous forest site

2005 ◽  
Vol 94 (2) ◽  
pp. 244-255 ◽  
Author(s):  
Quan Wang ◽  
Samuel Adiku ◽  
John Tenhunen ◽  
André Granier
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Deciduous Forest ◽  
Forest Site ◽  
Area Index ◽  
Relationship Of ◽  
The Relationship

scholarly journals Modeling light interception and distribution in mixed canopy of common cocklebur (Xanthium stramarium) in competition with corn

2010 ◽  
Vol 28 (3) ◽  
pp. 455-462 ◽  
Author(s):  
F. Vazin ◽  
M. Hassanzadeh ◽  
A. Madani ◽  
M. Nassiri-Mahallati ◽  
M. Nasri
Keyword(s):  
Leaf Area ◽  
Extinction Coefficient ◽  
Distribution Density ◽  
Yield Loss ◽  
Light Interception ◽  
Area Index ◽  
Corn Seed ◽  
Parabolic Function ◽  
Triangular Function ◽  
Height Model

The aim of this study was to model light interception and distribution in the mixed canopy of Common cocklebur (Xanthium stramarium) with corn. An experiment was conducted in factorial arrangement on the basis of randomized complete blocks design with three replications in Gonabad in 2006-2007 and 2007-2008 seasons. The factors used in this experiment include corn density of 7.5, 8.5 and 9.5 plants per meter of row and density of Common cocklebur of zero, 2, 4, 6 and 8 plants per meter of row. INTERCOM model was used through replacing parabolic function with triangular function of leaf area density. Vertical distribution of the species' leaf area showed that corn has concentrated the most leaf area in layer of 80 to 100 cm while Common cocklebur has concentrated in 35-50 cm of canopy height. Model sensitivity analysis showed that leaf area index, species' height, height where maximum leaf area is seen (hm), and extinction coefficient have influence on light interception rate of any species. In both species, the distribution density of leaf area at the canopy length fit a triangular function, and the height in which maximum leaf area was observed was changed by change in density. There was a correlation between percentage of the radiation absorbed by the weed and percentage of corn seed yield loss (r² = 0.89). Ideal type of corn was determined until the stage of tasseling in competition with weed. This determination indicates that the corn needs more height and leaf area, as well as less extinction coefficient to successfully fight against the weed.

scholarly journals Light Quality Environment and Photomorphological Responses of Young Olive Trees

Horticulturae ◽  
2021 ◽  
Vol 7 (10) ◽  
pp. 369
Author(s):  
Federico J. Ladux ◽  
Eduardo R. Trentacoste ◽  
Peter S. Searles ◽  
M. Cecilia Rousseaux
Keyword(s):  
Leaf Area ◽  
Light Quality ◽  
Plant Morphology ◽  
Cultivar Differences ◽  
Crop Species ◽  
Area Index ◽  
Canopy Development ◽  
Morphological Responses ◽  
Olive Trees ◽  
G Ratio

Tree densities have increased greatly in olive orchards over the last few decades. In many annual crop species, increased density reduces the horizontal red/far-red (R/FR) and blue/green (B/G) ratios during canopy development even before direct shading occurs, and such changes are known to alter plant morphology. This study with olive trees evaluated: (1) whether the leaf area index (LAI) of neighboring trees modifies the light quality environment prior to a tree being directly shaded and (2) the potential morphological responses of three olive cultivars to changes in light quality. Increasing LAI using different spatial arrangements of potted, three-year-old trees reduced the horizontal R/FR ratio more than that of the B/G ratio. Cultivar-specific responses to low R/FR ratio were observed for individual leaf area and aboveground/belowground biomass ratio using laterally positioned FR mirrors or green fences. No statistically significant responses were detected in response to green vegetation fences that reduced both horizontal R/FR and B/G ratios, but a cluster analysis grouped together the overall morphological responses to both FR mirrors and green fences. These results in olive trees suggest that cultivar differences in response to light quality may be relevant for understanding adaptation to dense orchards and identifying cultivars best suited to them.

Principal Canopy Factors of Sweet Corn and Relationships to Competitive Ability with Wild-Proso Millet (Panicum miliaceum)

Weed Science ◽  
2009 ◽  
Vol 57 (3) ◽  
pp. 296-303 ◽  
Author(s):  
Yim F. So ◽  
Martin M. Williams ◽  
Jerald K. Pataky ◽  
Adam S. Davis
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Competitive Ability ◽  
Sweet Corn ◽  
Canopy Closure ◽  
Crop Canopy ◽  
Area Index ◽  
Canopy Development ◽  
Proso Millet ◽  
Principal Factors

Univariate analyses fail to account for covariance among phenomorphological traits implicated in crop competitive ability. A more complete analysis of cultivar–weed interactions would reduce a number of important traits to a few underlying principal factors responsible for sweet corn competitiveness. Twenty-three commercial sweet corn hybrids from nine seed companies were grown in the presence and absence of wild-proso millet to (1) quantify the extent to which phenomorphological traits vary in sweet corn, (2) identify underlying principal factors that describe variation in crop canopy development, and (3) determine functional relationships between crop canopy factors and competitive ability. A principal component factor analysis revealed that 7 of the 18 weed-free crop traits measured at silking loaded highly (0.65 to 0.90) into the first factor, including plant height, shoot biomass, per plant leaf area, leaf area index, and intercepted light, as well as thermal time from emergence to silking and emergence to maturity. All seven traits were highly correlated (0.38 to 0.93) and were interpreted as a “late canopy and maturity” factor. Another five traits formed two additional principal factors that were interpreted as an early “seedling quality” factor (e.g., kernel mass, seedling vigor, and height at two-leaf stage) and a mid-season “canopy closure” factor (e.g., leaf area index and intercepted photosynthetically active radiation at six-leaf stage). Relationships between principal factors and competitive abilities were quantified using least-squares linear regression. Cultivars with greater loadings in the late canopy and maturity and canopy closure factors were more competitive with wild-proso millet. In contrast, crop competitive ability declined with cultivars that loaded highly into the seedling quality factor. The analyses showed that sweet corn's ability to endure weed interference and suppress weed fitness relates uniquely to three underlying principal factors that capture crop canopy development around emergence and near canopy closure and during the reproductive phase.

Relationship between tillering and leaf area index: quantifying critical leaf area index for tillering in rice

2002 ◽  
Vol 138 (3) ◽  
pp. 269-279 ◽  
Author(s):  
X. ZHONG ◽  
S. PENG ◽  
J. E. SHEEHY ◽  
R. M. VISPERAS ◽  
H. LIU
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Planting Density ◽  
Coefficient Of Determination ◽  
Area Index ◽  
N Input ◽  
Major Factors ◽  
The Relationship ◽  
Changing Light ◽  
Input Level

A field study was conducted at the International Rice Research Institute (IRRI), Philippines during the dry seasons of 1997 and 1998 under irrigated conditions. The objectives of this study were to quantify the critical leaf area index (LAIc) at which tillering stops based on the relationship between tillering rate and LAI, and to determine the effect of nitrogen (N) on LAIc in irrigated rice (Oryza sativa L.) crop. Results showed that the relative tillering rate (RTR) decreased exponentially as LAI increased at a given N input level. The coefficient of determination for the equation quantifying the RTR-LAI relationship ranged from 0·87 to 0·99. The relationship between RTR and LAI was affected by N input level, but not by planting density. The N input level had a significant effect on LAIc with a high N input level causing an increase in LAIc. Tillering stopped at LAI of 3·36 to 4·11 when N was not limiting. Under N limited conditions LAIc reduced to as low as 0·98. Transplanting spacing and number of seedlings per hill had little effect on LAIc. Results from this study suggest that LAI and plant N status are two major factors that influence tiller production in rice crops. The possibility that LAI influences tillering by changing light intensity and/or light quality at the base of the canopy where tiller buds and young tillers are located is discussed.

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