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Jens N. Wünsche and Alan N. Lakso

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 (r 2 = 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.

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Carlos Campillo, M.I. García, C. Daza, and M.H. Prieto

the plant in the biomass ( Gifford et al., 1984 ). One estimate of a crop's ability to capture light energy is the leaf area index (LAI). The concept of the LAI was first introduced by Watson (1947) and defined as the ratio of leaf area to a given

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Angela Knerl, Brendon Anthony, Sara Serra, and Stefano Musacchi

sunlight transmission through the canopy onto the lens, or sunflecks, were avoided by measuring early in the morning. Fig. 2. A comparison of the difference between estimated leaf area index (LAI) and defoliated LAI for 30 combinations of light environment

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Toshio Shibuya, Akihito Sugimoto, Yoshiaki Kitaya, and Makoto Kiyota

humidity. The air velocity at 5 mm above the leaf surface under each plant density condition was measured with a hot-wire anemometer (Anemomaster Model 6071; Kanomax Japan, Inc., Suita, Japan) at the end of each set of measurements. Leaf area index (LAI) of

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Tadahisa Higashide, Yuya Mochizuki, Takeshi Saito, Yasushi Kawasaki, Dong-Hyuk Ahn, and Akio Ohyama

mature-trimmed plants. There was no significant difference in LUE between untrimmed and mature-trimmed plants. Table 3. Effects of leaf trimming on leaf area index (LAI), specific leaf area (SLA), fresh weight (FW) fruit yield, dry weights of leaves

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Rhuanito S. Ferrarezi, Alan L. Wright, Brian J. Boman, Arnold W. Schumann, Fred G. Gmitter, and Jude W. Grosser

(vertically and along the north–south and east–west lateral axes), and the three diameters averaged together to calculate the tree’s canopy surface area (assumed shape was a sphere for surface area calculations). Leaf area index. LAI measurements were taken in

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Xiaofeng Yang, Gang Li, Weihong Luo, Lili Chen, Shaopeng Li, Ming Cao, and Xuebin Zhang

), PTI sum (MJ·m −2 ) is the accumulated PTI since planting date, LAI max (m 2 ·m −2 ) is the maximum value of LAI, r LAI [(m 2 ·m −2 )/(MJ·m −2 )] is the increasing rate of LAI. Fig. 6. Relationship between leaf area index (LAI), partitioning index

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Silvia Jiménez, Mónica Pérez, Blanca María Plaza, Roberto Salinas, and María Teresa Lao

, such as temperature, vapor pressure deficit (VPD), and Rg, and to growth parameters such as leaf area index (LAI). In addition, the influence of the N form supply (NO 3 – -N or NH 4 + -N) on P uptake and on the defined as the ratio of P and water

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Xiaofeng Yang, Lianzhu Chen, Ming Cao, Xuebin Zhang, and Shaopeng Li

and B . LAI was described as Eq. [8] by curve fitting the data in Expt. 1. LAI = LA I 0 + LA I max × ( 1 − exp ( − rLAI × PT I sum / LA I max ) ) , [8] Fig. 5. Relationship between leaf area index (LAI), partitioning index of shoot (PISH

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Rahmatallah Gheshm and Rebecca Nelson Brown

leaf area index (LAI), fresh weight, and dry matter content (DMC) of romaine lettuce grown in the high tunnel in two seasons. Cultivar effects . Compost mulch affected all cultivars similarly, with no significant interaction effects. Yields were higher