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Thesis (M.S.)--Virginia Polytechnic Institute, 1965. / Vita. Abstract. Includes bibliographical references (leaves 52-54). Also available via the Internet.

Fruit-growers in the lower mainland of British Columbia are facing a potential labor shortage for hand harvesting of fruit. Prices paid to hand picking labor have increased by more than 100 percent in the last three years. These factors have prompted interest in mechanical harvesting methods. The purpose of this research was to investigate the feasibility of introducing mechanical harvesting methods in raspberry production and to determine optimum machine parameters. A review of methods used for determining the optimum size of agricultural equipment was conducted and the methods were summarized. Due to the nature of small fruit production some commonly used methods were not applicable and modifications were necessary. A fruit yield function and a timeliness function were developed for Willamette raspberries. The fruit yield function based on actual yield data, was used for determining the potential income from a raspberry plantation. The timeliness function, based on the reduction of fruit quality due to variations in the length of the interval between subsequent harvests, was used to determine a suitable charge for untimeliness at any part of the harvest season. An optimum fruit removal efficiency for mechanical harvesting of Willamette raspberries was determined by assessing the loss in potential income due to the removal of green fruit and the production of over mature fruit. This was based on published results of mechanical harvesting trials. Results indicated that the mechanical harvesting of raspberries could be potentially much more profitable than hand harvesting. A machine with a fruit removal efficiency of 80 percent and with an operating speed of 1.5 miles per hour, or greater, appeared to be optimum. At operating speeds above 1.5 miles per hour, the cost of mechanical harvesting was not significantly influenced by the purchase price of the harvester. The cost of untimely operation was large. Extending the interval between subsequent harvests by one day resulted in an annual profit reduction of approximately 200 dollars per acre. / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate

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Thesis (M.Sc. (Plant Production)) -- University of Limpopo, 2014 / Wild medlar (Vangueria infausta subsp. infausta) is a popular indigenous fruit available and consumed by rural communities in Limpopo Province, South Africa. Inadequate post-harvest practices in indigenous fruit plants including V. infausta fruit forms major constrains in expanding their production. There is scanty information documented on neither objective nor subjective harvesting indices of indigenous fruit plants consumed by locals in sub-Saharan Africa. Thus, the objective of this study was to determine the effect of harvesting time on physico-chemical properties and selected nutritional composition of V. infausta fruit. Fruits were harvested twice, where two harvesting times were regarded as treatments and each tree as replication. The reduction for fruit weight, sugar content and sugar/acid ratio was highly significant (P ≤ 0.05), whereas for average fruit diameter, seed weight, acid ratio and pH content this may imply that the listed parameters are treatment which was non-significant (P ≤ 0.05). The treatment reduced P, K, Mn and Fe by 33%, 18%, 3% and 7%, respectively. On the other hand, treatments had no effect on N and Ca. The reduction of phosphorus was highly significant (P ≤ 0.05), whereas for N, K, Ca, Mn and Fe treatment impact was non-significant (P ≤ 0.05). Similarly, the treatment consistently reduced moisture content and increased dry matter and crude protein of V. infausta by 76%, 300% and 7%, respectively. The reduction of moisture content, increase in dry matter was highly significant (P ≤ 0.05), whereas crude protein treatment impact was non-significant (P ≤ 0.05). The data indicated that the best time to harvest V. infausta fruit was during January when fruits were cosmetically appealing and not wrinkled. This study demonstrated that there was less variation in some measured objective harvesting indices of V. infausta fruit harvested at two harvesting time. More work would be required to do physico-chemical properties and selected mineral elements analysis from wide growth habitat for conclusive recommendations.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

From the results of this study the following conclusions can be drawn. All conclusions are based on statistical ABOVA tests at a five percent level of significance. 1. Baaed on 108 detachment tests, it can be concluded that the difference in rate at which the loads were applied to the stem, which were 0.175 and 0.350 in./sec did not affect the force of removal. 2. Based on 108 detachment tests, it can be concluded that the angle at which the load was applied to the stem did affect the force of removal. The loading angles used were 90, 60, 30 and 0 degrees. 3. Two, 4-day differences in the stage of maturity did not affect the detachment force. 4. Each individual stem exhibited non-linear stress-strain properties since the calculated apparent elastic modulus in bending decreased as stem deflection increased. S. The rate of applying the load to the stem influenced the calculated apparent elastic modulus values. / Master of Science

Thesis (MSc .(Plant Production)) -- University of Limpopo, 2016 / Delayed fruit harvest (DFH) or on-tree-fruit storage is a strategy being considered to extend the harvest season of late maturing ‘Reed’ avocado. However, avocado fruit growth beyond physiological maturity is accompanied by alterations in chemical and physical properties. Thus, the study aimed to investigate the effects of delayed harvest on tree productivity, mineral nutrition and post-harvest quality of late maturing ‘Reed’ avocado and further to evaluate the fruit quality response to varying ripening temperature regimes. As treatments, fruit were harvested early, mid and late in the season, with one month apart from each harvest during 2013 and 2014 seasons. Yield and fruit size were recorded at harvest. During each harvest time, two sets of fruit samples were collected to determine the fruit nutritional content while the second set was cold stored at 5.5°C for 28 days. After storage, fruit were ripened at 16, 21 or 25°C and evaluated for post-harvest disorders, pathological diseases and fruit physico-chemical properties. Yield dropped from 42 to 12 kg/tree from early to late harvest during 2013, while treatments showed no effect during 2014. Furthermore, treatments had no effect on fruit size during both seasons. Phosphorus content decreased by 40 and 23% from early to late harvest time during 2013 and 2014 seasons, respectively. Similar decreasing patterns were observed for K, Ca and Mg content. Zinc content remained constant during 2013; however, mid-season fruit maintained higher zinc levels during 2014 season when compared to early and late harvest time. Protein content was constant for early and mid-season fruit but significantly decreased during the late harvest in both seasons. Moisture content decreased from 74.0 to 65.0% from early to late harvest during both seasons. Starch, oil and ash content were high during late harvest time in both seasons; while crude fibre was high during the mid-harvest time when compared with early and late harvest time. Internal chilling injury increased with maturity and ripening temperature. In both seasons, higher temperatures induced higher anthracnose incidences during early and mid-harvest compared with late harvest time. Similarly, vascular browning was high on fruit ripened at 16°C during early and mid-harvest time but decreased on late harvest fruit during 2013. However, low ripening temperatures induced high incidences of vascular browning during 2014 season. Stem-end rot was high on fruit ripened at 16°C than 21 and 25°C during 2014 season. xvi Physico-chemical quality parameters showed similar behaviour in both seasons. Fruit lightness increased with ripening time regardless of ripening temperature during the early harvest, but remained constant during mid and late harvest. Hue angle (h0) and Chroma (C*) values were slightly reduced during ripening. Fruit ripened at 25°C had the highest respiration rate and reached a climacteric peak earlier (day 2) than fruit ripened at 21 and 16°C (day 4). Fruit firmness and weight loss were high and rapid at 25°C followed by 21 and 16°C regardless of the harvest time. Delayed harvest had no effect on yield and fruit size. Generally, nutritional content of avocado fruit increased with fruit maturity. Furthermore, fruit maturity played a major role in the response of fruit to ripening temperature. Higher temperature enhanced fruit ripening, but was conducive for development of post-harvest diseases. Keywords: Harvesting time, nutrition, yield, fruit size, ripening temperature, post-harvest quality