No description available.

In farming of fruit trees it is of interest to know the light interception of the trees. Therefore, in this project, a geometric model of the trees was derived using LiDAR data and this was combined with a sky model to estimate the light interceptionof orchard trees. The light interception was estimated by first synthesising a discrete model of the hemispherical sky, which holds a measure of global lightradiation in each node. The light interception of the trees was then estimated by ray tracing from the sky, applying a radiation absorption model where rays passed the point cloud representation of the trees. Comparing the interception model to measurements of photosynthetically active radiation (PAR) underneath a tree, the qualitative agreement was high and the quantitative analysis showed a reasonable, albeit noisy, correspondence between the model output and the real world measurements. When comparing the estimations produced by the solar-geometry model and the tree volume (estimated also with LiDAR), a correspondence between the surface area of the tree and the interception was found. When comparing tree volume and light interception against actual yield numbers (total weight, average fruit weight and fruit count per tree), the observable trend was that light interception did better in predicting the average fruit size, while the volume did a better job of estimating the two others. The results were encouraging, however, because ground truth data were only available for 18 trees, future work will have to compare with a greater number of measurements over multiple growing seasons.

No description available.

Seasonal phenology and mating frequency of moths in the genus Dioryctria found sympatrically in north Okanagan Valley, British Columbia seed orchards were assessed. Female moths in the abietella, auranticella, ponderosae and schuetzeella species groups were trapped in Douglas-fir, lodgepole pine and interior spruce stands. Most species were univoltine based on one peak of flight activity per season. There is evidence that the abietella group are bivoltine in this region. Females in the abietella and auranticella groups are polyandrous; ponderosae and schuetzeella females are monandrous. The sole abietella species, D. abietivorella, recorded in British Columbia can have substantial economic impacts on seed production in commercial seed orchards. Factors influencing reproductive behaviour, longevity and fecundity of D. abietivorella were investigated. Females are synovigenic and have an income-breeding mating strategy. Reproductive behaviours are delayed post-eclosion and signalling receptivity by females coincides with egg maturation, increasing with age. Female D. abietivorella experience trade-offs between reproduction and longevity. / Ecology

Thesis (M.S.)--University of Kentucky, 2008. / Title from document title page (viewed on March 18, 2008). Document formatted into pages; contains: viii, 73 p. : ill. (some col.). Includes abstract and vita. Includes bibliographical references (p. 67-72).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1969. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

In the spring, apple orchards are susceptible to freeze damage. Various approaches to orchard protection have been used in the past. Overhead sprinkling for bloom delay has been effective in extending to a later period in the spring the freeze hardiness of apple buds. Thus, protection against a late spring freeze is obtained. Previous research has not been conducted to determine optimum sprinkling times in the spring, the most effective threshold temperature, the amount of water needed to provide adequate bud protection, and the daily length of sprinkling time. A 2-year investigation was conducted with the objective of obtaining basic information to help in system design and the operational aspects of overhead sprinkling. The experiment was designed to determine the effectiveness of a system sprinkling beginning at the end of rest and at Celsius growing degree hour accumulations relating to stages bud development. The evaluation of limited and unlimited water use and the relation to bloom delay was obtained. The two sprinkler types studied were umbrella and impact. On the umbrella sprinklers, four cycling times (1/2, 1/3, 1/4, and 1/6 time) and three threshold temperatures (7, 10, and 13 C) were tested. On the impact sprinkler, three nozzle sizes (4.0, 3.6, and 2.8 mm) were evaluated. The investigation answered many questions, the most important of which were: (1) when only limited bloom delay is needed, more freeze protection can be obtained by sprinkling in the early spring than in the late spring; (2) bloom delay can be regulated by terminating sprinkling at different stages of bud development; (3) to obtain maximum delay, sprinkling should begin at the end of rest and a low threshold temperature for sprinkling should be used for sprinkler initiation; (4) when limited delay is required, greater efficiency of water use can be obtained by lowering the threshold temperature and lowering the application rate.

‘Wonderful’ pomegranate flowering and fruiting habits are not well understood. Characterizing any relationship between flowering habit and fruit size and quality could lead to effective cultural practices for producing high-value fruit. Five mature ‘Wonderful’ pomegranate trees were monitored every 5-14 days throughout the 2015 growing season. Newly emerged flowers were tagged and characterized with respect to sex (determined by ovary shape and style length at anthesis), clustering habit, age of wood on which floral buds were borne, and direction of wood growth. More than 1,100 hermaphroditic flowers were identified and ovary/fruit diameter was recorded throughout the season. In addition to tagging 1,800 staminate flowers at anthesis, approximately 14,000 abscised staminate flowers were collected and used to estimate total flower number and the ratio of hermaphroditic (fruit producing) to staminate flowers. Trees were strip picked at harvest. Fruit weight, maximum hemispheric diameter and exocarp color were recorded. Arils (seeds with a fleshy seed coat) were removed and weighed; aril number was estimated from the weight of 100 arils, and aril titratable acidity and total soluble solids were measured. The age of wood on which flowers were borne was a significant predictor of flower sexual condition. One-year-old wood produced the highest number of flowers (70% of total) with the smallest proportion of hermaphroditic flowers (5%) for any age of wood. Two-year-old wood produced fewer flowers (19% of total) with 10% hermaphroditic flowers. Wood that was greater than two years old produced 10% of total flowers and 20% were hermaphroditic. Overall, 93% of the flowers were staminate. Despite the low proportion of hermaphroditic flowers produced on one-year-old wood, 57% of marketable sized fruit were produced on one-year-old wood. There were three distinct bloom periods, the first lasting approximately 6 weeks. Bloom time was highly predictive of fruit quality. Late-blooming flowers produced low-quality fruit that were smaller in diameter with fewer arils and poor exocarp color. Such fruit accounted for approximately 13% of total fruit weight. Location within the canopy influenced fruit diameter significantly. Flowering rarely occurred in the typically “closed” interior of the canopy and flowers in the northwest tree quadrant were less likely to be early blooming or hermaphroditic than flowers in other quadrants. The results suggest that development of cultural methods that limit excessive production of staminate flowers reduce late-season flowering and/or fruit production and/or increase light exposure to fruiting wood could increase the production of high-value fruit for ‘Wonderful’ pomegranate.

To advance crop monitoring techniques in horticultural tree crops, earlier research has examined the relationship between crop vigor (height, canopy den- sity, health) as assessed by remote sensing technologies and aspects such as fruit quality and yield requirements. In recent years, structure-from-motion image pro- cessing techniques have been widely used to generate orthomosaics and 3D point clouds from RGB and multispectral (MS) imagery acquired by unmanned aerial vehicles. However, this process requires a lot of computing power and can be expensive, especially for large commercial orchards. However, studies have been scarce comparing the accuracy of different remote sensing technologies in deter- mining tree height and plant area index. Light detection and ranging (LiDAR) is an alternative method to generate 3D point clouds that requires less compu- tational power. This study assessed the accuracy, processing parameters, and limitations of UAV-based RGB, MS, and LiDAR data for measuring cherry trees’ height and plant area index in a high-density orchard in Malauc`ene, southeastern France. Furthermore, the plant area index changes of 5 different cherry culti- vars were assessed during the growth cycle. Overall, the LIDAR data provided the highest accuracy for tree height measurements around harvest (R² = 0.923, RMSE = 0.215 m) and the beginning of leaf senescence (R² = 0.863, RMSE = 0.218 m). LiDAR-derived plant area index also produced the best accuracy at May (R² = 0.48 and RMSE = 0.42) and October (R² = 0.45 and RMSE = 0.59). Our findings demonstrate that UAV-based LiDAR data provide an effective and rapid means for measuring cherry tree height and plant area index over time. Such information can serve as a general indicator of tree health and aid growers in making informed agricultural crop monitoring and management decisions.

Experiments were conducted in the field, greenhouse, and controlled environment chambers to study the effect of environmental factors on tillering, growth, and carbohydrate content of orchardgrass. Tillers of one genotype were studied with several variable factors (light, temperature, moisture,. nitrogen, and/or defoliation) in each of four experiments. Factorial treatment combinations were used in each of the four experiments to study single factors and interactions. Tillering declined to 73 and 26% of normal light when light intensity was reduced in the greenhouse and field, respectively. In the controlled environment chambers, tillering rates were higher with an 18-hour than for a 9-hour day with 3100 F.C. in both chambers. Soluble carbohydrates in the stubble were associated with tillering. There was a marked increase in water soluble carbohydrates as light energy increased up to normal sunlight. Ory matter production was associated with tillering and carbohydrate contents of orchardgrass, factors which increased tillering augmented clipping dry weights. Tillering and foliage growth were much higher when day temperature was 80*F. as compared with 60°F. There was a sharp increase in soluble carbohydrates with low temperature, but at the high temperature carbohydrates did not accumulate as they were apparently utilized for fast growth and tillering. Carbohydrate accumulation per se was not associated with tillering nor yields when temperatures were sub~-optimum for fast growth. Tillering was increased 30% by irrigation. Tillering of orchardgrass plants, defoliated to 1.5, 3, and 6 inches in combination with other treatments, showed increased tillering and dry matter production as defoliation intensities were relaxed. High tillering rates were associated with the magnitude of carbohydrates in orchardgrass stubble. Root development at the end of the experiment was much poorer for intensive defoliation as compared with lax defoliation. Nitrogen stimulated tillering and retarded soluble carbohydrate accumulation in orchardgrass stubbles, Nitrozen stimulated the production of new tissue and nitrogen compounds at the expense of stored carbohydrates in the stubbles. With slow orchardgrass growth under low nitrogen, soluble carbohydrates in the stubble accumulated. There was good evidence that soluble carbohydrates are directly associated with tillering and growth of orchardgrass when factors such as light, nitrogen, and water do not limit growth. Carbohydrate accumulatpeiro nse is not associated with tillering, if any environment growth factor is sub-optimum for tillering and growth. sub-optimum for tillering and growth. / Ph. D.