Browsing by Subject "Olive"
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Item Effects of drought stress and climatic conditions on Olea europaea L. physiology and fruit set(2012-08) Baliga, Vikram; Montague, David T.; McKenney, Cynthia B.; Cox, Robert D.Production of olive oil in the State of Texas is a relatively young yet rapidly expanding industry. Climates in several parts of Texas closely resemble semi-arid areas in which olive trees (Olea europaea L.) are cultivated worldwide. However, there is little research to date on physiological responses of olive cultivars grown in Texas to drought stress and influences of climate on flowering date and fruit retention. Researchers conducted a 2010-2011 study to evaluate changes in physiological response in 4 cultivars of greenhouse grown olive trees when exposed to three irrigation treatments (high, medium, and low; irrigated daily, every other day, and every fourth day, respectively). This study also sought to identify climate, location, and cultivar effects on flowering date and fruit retention in several existing Texas olive orchards. Results indicate cultivars ‘Arbequina’ and ‘Koroneiki’ were most able to maintain levels of physiological response, in terms of photosynthetic rate, stomatal conductance, and water use efficiency across all irrigation levels. Additionally, there were few significant differences between high and medium irrigation treatments overall. However, differences were found between medium and low treatments. Studies also indicate location and cultivar had an effect on fruit load. Olive orchards located farther south in the state flowered earlier in the year and retained fruit more effectively throughout the growing season. ‘Arbequina’ also set and retained at least a small amount of fruit across every orchard in which it was planted.Item Physiological response of Olea europea L. to variable irrigation regimes(2012-05) Whitehurst, Kaylee; McKenney, Cynthia B.; Montague, David T.; Cox, Robert D.Olives are a historic horticultural crop in the Mediterranean where a long, hot growing season and a relatively cool winter with minimum temperatures make it the perfect climate for growing this crop. An increase in the global demand for olive products, especially olive oil, has led to many countries outside the Mediterranean to develop extensive olive production areas. Olive oil is a staple in most Mediterranean diets and has been linked to improving health quality with its free-radical scavenging properties, and has gained popularity around the world. New olive orchards are typically high-density orchards that range from 200 – 300 trees per hectare, to a super-high density system of 1,500 – 2,500 trees per hectare. A benefit to high-density orchards is the ability to mechanically harvest the crop, which cuts down on labor costs for the orchards. These high-density orchards rely on supplemental irrigation systems to meet the needs of the plants. Additional irrigation can cut the amount of time it takes to bring an orchard into full production and possibly eliminate the alternate bearing characteristic of olive trees. However, with water supplies rapidly depleting, it is important for olive growers to be able to limit irrigation without harming the overall health and production of the trees. Olives are a drought tolerant crop and there has been extensive research completed in the Mediterranean area to understand how drought affects the trees in that area. However, there is limited research available for newer production areas, and none of that is specific to the south Texas production area. Therefore, the purpose of this research was to understand the physiological effects of drought on olives in south Texas. The field portion of this research took place at three different olive orchards in Texas: Texas Olive Ranch in Carrizo Springs, Conly Olive Orchard in Asherton, and Central Texas Olive Ranch in Walburg. At each orchard three different levels of irrigation, low, medium and high, were applied to the established ‘Arbequina’ trees. During the growing season, May – August, monthly mid-day stomatal conductance and SPAD readings were taken in 2010 and 2011. Shoot growth was measured at the end of each growing season. At Texas Olive Ranch in September 2010, individual olives were harvested from the trees under the different levels of irrigation. Overall means at the three orchards indicated little difference in stomatal conductance between the different irrigation treatments, indicating that less water can be applied without physiologically harming the trees. The greenhouse portion of this research was conducted to evaluate the effects of drought on four different olive varieties when subjected to varying levels of fertility. Four fertility treatments (control, low, moderate, and high) were applied to ‘Arbequina’, ‘Arbosona’, ‘Koroneki’ and ‘Mission’ olives. These trees were then subjected to two different drought experiments, acute and sequential. Mid-day stomatal conductance, leaf temperature and pre-dawn leaf water potential measurements were taken and indicated that ‘Arbequina’ can withstand the effects of drought better than ‘Mission’. Also increasing fertility rates enhance the effects of drought regardless of variety. Both the greenhouse and field studies play a role in better understanding the effects of drought on olive trees.Item The effects of olive pomace on the fatty acid profile and weight gain in Capra aegagrus hircus as a model for ruminants(2017-04-03) Urso, Philip M.; Beverly, Marcy M.; Kelley, Stanley F.; Anderson, Mark J.In the livestock industry, feed is one of the highest variables affecting the cost of production. Olive pomace is a by-product of the olive oil industry and could be considered as a potential livestock feedstuff to be used as an energy supplement due to its high fat content (15%) and can potentially alter the biochemical composition of blood and muscle tissue. This project was split into two phases; the objective of phase I was to determine if olive pomace could be used as an acceptable low cost feedstuff to maintain weight during the colder winter months. To accomplish this, 28 Spanish influenced goats were fed (2% of body weight, BW) varying amounts of fermented pomace with a protein pellet to meet NEm requirements. The four test groups (n=7) consisted of a 3:1, 1:1, and 1:3 olive pomace to concentrate ratio (O:C) as well as a control containing no pomace. All groups received molasses at 0.5% BW to improve the palatability of the feed and to further homogenize the ration to discourage selective eating of the mixture. Does were fed in herring bone style runs every morning for 49 days. The average daily gain (ADG) for the 1:3, 1:1, 3:1 and control groups were 0.0370, 0.0166, 0.0119, and 0.0262 kg/day, respectively with no difference detected between groups (P>0.88). A difference (P<0.001) in consumption rates was detected between treatments with the 3:1 group consuming more feed with an average of 0.785 kg/day compared to the control at 0.694 kg/day. Additionally, olive pomace may be consider as a cost effective supplement to reduce costs for maintenance rations. Ration costs were calculated at $0.153/kg for the 3:1 ration compared to $0.6386/kg for the pelleted control ration. On average, this difference in input cost can reduce a producer’s cost of feed by $13.53/hd over a 49 day maintenance feeding period (P<0.001) by feeding olive pomace. The objective of phase 2 was to determine if olive pomace could be supplemented at a level that increases the C18:1 concentration in blood. Mature Spanish-influence goats (n=14; 41.6 kg) were fed ad libitum olive pomace, starting at 2% of their BW for 28 days to determine if this by-product would alter circulating fatty acid content. Molasses was mixed with the ration at 0.5% BW to improve the palatability of the feed. Does were fed in herringbone-style runs every afternoon and BW and blood samples were collected every two weeks. There were significant changes in C18:1 and C18:2 over time with mean consumption of 0.55 kg/d over the duration of the trial. From d 0 to d 28, the serum concentration of C18:1 increased (P<0.001) by 8.67% and C18:2 increased (P<0.03) by an average of 4.38%. Serum concentration of C18:0 increased by 3.59% but this was not significant. There was also no significant increase in C16:0. If C18:1 is deposited in the muscle tissue as a result of increased concentration in the blood, then feeding olive pomace can be a healthy alternative to high starch ingredients such as corn and barley.