Grant Information
| Knowledge Area | Subject of Investigation | Field of Science | Percent |
|---|---|---|---|
| 204 - Plant Product Quality and Utility (Preharvest) | 199 - Soil and land, general | 1020 - Physiology | 100% |
Florida may now be positioned to be the only major producer of low-chill stone fruit (peaches) in the mainland United States. While traditional perennial crops are highly sensitive to interstate competition, low-chill stone fruit is unlikely to face the same challenges if producers can take advantage of short production windows from the late March to early May when no other peaches are on the market. However, producing high-quality peach with a good fruit size in the optimum market window has been one of the main challenges for peach producers in Florida due to excessive vegetative growth. This project will test the feasibility of different horticultural strategies to be used as a management tool in low-chill peach production. The growth control of low-chill peach is of great importance in orchard management for sustainable production. Excessive vegetative growth not only causes an increased competition among and within individual trees for resources, but also reduces the light interception and distribution inside the canopy. Therefore, excessive vegetative growth negatively impacts fruit yield, quality, and disease and pest management. Also, conventional methods to control vigor, such as shoot pruning, can be time-consuming, labor-intensive, and expensive, especially in a tropical climate where the growing season is long and conducive for excessive vegetative growth. Improving peach fruit size is of great importance in peach orchard management for sustainable production. Developing alternative methods either to integrate them with the conventional thinning method or applying them as independent methods for improving fruit size while maintaining fruit sensory quality is essential for developing a successful low-chill stone fruit production system in Florida. While annual fertilization practices are commonly used by peach growers in Florida, there is limited knowledge about the ideal quantity and timing of fertilizer application for this crop under Florida climate. In addition, it has been observed that there may be consequential, undesirable impacts of some nutrient applications upon soil pH. This has been especially noted for some fertilizers and results in nutrient imbalances and deficiencies. It has also been observed that unabsorbed or unsequestered nutrients associated with current peach fertilization applications may serve as a source of pollution, particularly in sandy soils. In order to implement more sustainable peach production practices, information is needed to coordinate the application of fertilizers to the associated growth and pattern of uptake and utilization of nutrients for the various stages of growth of peaches. This effort requires a sophisticated understanding of phenological stages of the growth of low-chill stone fruit and the determination of nutrient requirements for each of these phases of growth. Therefore, developing alternative methods to manage tree canopy vigor will improve orchard efficiency by improving pest/disease management, increasing fruit yield, and decreasing production costs. This project will test the feasibility of different methods for improving fruit size (i.e., considering fruit location in the canopy during conventional thinning and applying fruitlet abscission/fruit size inducing chemicals) to develop a strategy that can be applied as a management tool by producers in Florida. In addition, this project will examine the feasibility of developing a new and improved nutrient management programs for low-chill stone fruit to improve the productivity and profitability of producers who grow peaches while minimizing potential adverse environmental impacts. Additionally, this work may help us better understanding the role of managing the leaf nutrient status within the low-chill stone fruit.
The objective of this project is to develop sustainable production practices for low-chill stone fruit production. Specific objectives of this project include;
Vigor control strategies (i.e. root pruning, root bagging and PGRs) will be applied to field grown peach trees. Root pruning will be applied using a tractor mounted vertical knife that cuts the roots to a certain depth on both sides of the tree. The root pruning treatments will be applied at three different times: before bloom, at full bloom, and in summer. Root bagging will be used to restrict root growth and as a consequence control the growth rate and fruitfulness of fruiting of some tree fruit such as apple, pear, and peaches. The bags were designed to be used above ground or buried in the soil. Basically, roots of a tree will not pass through a pore size (or hole in a bag) smaller than its own diameter. The density of holes in the bag slows drainage rate of water applied to allow even distribution of water within the soil in the bag without causing water logging problems. Above ground bag's material is guaranteed UV stable for over 10 years. Below ground the material is protected from UV rays, and is also designed not to rot or deteriorate. Plant growth regulators will be tested in peach seedlings and trees under both controlled environment and field conditions. KUDOSâ„¢ 27.5 WDG is federally (including Florida) registered and labeled for tree canopy management in apple, pears, and sweet cherries, and for shortening internode in peanut. If the results of this proposed study indicate that KUDOSâ„¢ 27.5 WDG is effective as a canopy management tools in low-chill peaches, the registration and labeling process of this plant growth regulators for commercial uses will be accelerated, as it was already labeled and registered in Florida for few fruit crops. For KUDOSâ„¢ 27.5 WDG, application time, the effective rate, and the best application method (foliar or soil application) will be determined.Orchards will be surveyed over multiple counties, regions and years to begin building tissue nutrient concentrations. This information will be pooled and correlated with tree growth and development, flowering, fruit yield, and quality. This objective aims to provide Florida low-chill stone fruit growers with the best nutrient management program and alternative management tools to increase profitability with respect to following objectives. We will determine the effects of crop load on seasonal patterns of both macronutrient (N, P, K, Ca, Mg, S) and micronutrient (Fe, Zn, Cu, Mn, Mo, B) concentrations of perennial and annual tissues in different phenological stages. We will identify how these patterns may impact the abscission of floral buds, vegetative growth, and fruit set resulting in producing small size or big size fruit. Analyzing leaf-nutrients is the most effective method for identifying tree nutritional status. It indicates an essential tool for defining low-chill stone fruits fertilization/foliar requirements and programs. Factors affecting fruit quality include distribution of light in the canopy, tree training and pruning, crop load, pest and disease control, and irrigation all of which are significantly affected by tree nutrient status.Established extension methods such as seminars, workshops, regional, state and national meetings will disseminate research results in-person. Electronic outreach will include audio-video (YouTube) of selected extension program presentations, webinars through eXtension and online available, pdf versions of PowerPoint presentations and project PI interviews. In addition, research results will be published in refereed (e.g., HortScience and Plant Disease) and non-refereed publications [e.g., UF/IFAS Electronic Digital Information Service (EDIS), Proceedings of the Florida State Horticultural Society, newsletters, and trade magazines]. Clientele at in-person programs will be surveyed to evaluate knowledge gained, behavior changed (or likely to change), and economic impact (or potential impact).
Target Audience
The primary target audiences for this project are low-chill peaches producers in Florida aer growers,research and extension scientists, extension agents, and other stakeholders who are in business with low-chill stone fruit production. Our initial result communicated to growers, extension agents, researchers, and to the general public through diffrent extesion venues.
Changes / Problems
Nothing Reported
Training & Professional Development
Shirin Shahkoomahally, Ph.D. student; Trequan McGee, Ph.D. student; Logan MarieRichmond-Cosie, M.S. student; Dustin Huff, Biological Scientist
Dissemination Streams
The primary target audiences for this project are low-chill peaches producers in Florida, research and extension scientists, extension agents, and other stakeholders who are in business with low-chill stone fruit production. Our initial result communicated to growers, extension agents, researchers, and to the general public through following venues: -Extension publication "Thinning Florida Peaches for Larger Fruit" https://edis.ifas.ufl.edu/pdffiles/HS/HS132400.pdf -Developing grower email list STONEFRUIT-GROWERS-L@LISTS.UFL.EDU, which includes over 150 emails. -Web page: Stone Fruit at the University of Florida http://old-hos.ifas.ufl.edu/extension/stonefruit -Facebook: Stone Fruit at the University of Florida https://www.facebook.com/stonefruitUFIFAS/
Next Reporting Steps
The next setp of the projet is determine the influence of fruit location within the canopy on fruit size and quality. We will find which part of the canopy (bottom, mid, top) and which side (N, S, E, W) of the tree can deliver the most marketable fruit with an optimum size. If proven, growers would be able to localize flower buds or fruitlets in the right spots by their pruning and thinning practices. Also, to determine diffrences among Prunus spp. rootstocks in their tolerance to flooding stress as indicated by their physiological and biochemical responses.
Target Audience
The primary target audiences for this project are low-chill peaches producers in Florida, research and extension scientists, extension agents, and other stakeholders who are in business with low-chill stone fruit production. Our results will be communicated to growers, extension agents, researchers, and to the general public through different channels. Some of these dissemination efforts will be done throughout the state, growers and professionals from other regions will have access to our results. As a consequence, the outcomes of the extension efforts, there will be an increased number of growers that are well informed on available tools for producing peach and other low chill stone fruit (i.e. nectarine and plum).
Changes / Problems
Nothing Reported
Training & Professional Development
Shirin Shahkoomahally, Ph.D. student, Yuru Chang, M.S. student, Dustin Huff, Biological Scientist, Austyn Sanches, undergraduate studen
Dissemination Streams
The primary target audiences for this project are low-chill peaches producers in Florida, research and extension scientists, extension agents, and other stakeholders who are in business with low-chill stone fruit production. The results of this research was published as scientific paper in journal of Food Science & Nutrition. Title: Influence of rootstocks on fruit physical and chemical properties of peach cv. UFSun Link: https://onlinelibrary.wiley.com/doi/full/10.1002/fsn3.2005
Next Reporting Steps
Toinvestigate the physiological response of six Prunus rootstocks grafted with cv. UFsun to flooding of the root zone. Leaf gas exchange (A and gs), ROS, enzymatic antioxidant activity, antioxidant metabolite content, osmolyte content, and leaf mineral nutrient content were used to assess physiological responses to flooding. The hypothesis tested was that the six Prunus spp. rootstocks differ in their tolerance to flooding stress. <br><br>
<br>What was accomplished under these goals? Production of high?quality fruit is an important consideration, not only for peach growers, but also for consumers looking to benefit from the fruit's health?promoting effects; thus, it is necessary to obtain information on which scion-rootstock combinations would produce optimum fruit quality. This study aimed to determine the variability of physical and chemical properties of the subtropical 'UFSun' peach grafted on five different rootstocks. <br><br><b>Publications</b><br>
Target Audience
The primary target audiences for this project are low-chill peaches producers in Florida, research and extension scientists, extension agents, and other stakeholders who are in business with low-chill stone fruit production. Our initial result communicated to growers, extension agents, researchers, and to the general public through following venues: -Extension publication " https://edis.ifas.ufl.edu/topic_peaches_and_nectarines -Developing grower email list STONEFRUIT-GROWERS-L@LISTS.UFL.EDU, which includes over 150 emails. -Web page: Stone Fruit at the University of Florida http://old-hos.ifas.ufl.edu/extension/stonefruit -Facebook: Stone Fruit at the University of Florida https://www.facebook.com/stonefruitUFIFAS/ - Blog: Operation Peaches in Florida https://ufstonefruit.wordpress.com/ - 2019 Unuversity of Florida Annual Stone Fruit Workshop/Field Day, which over 130 clienteles joined the field day.
Changes / Problems
Nothing Reported
Training & Professional Development
Shirin Shahkoomahally, Ph.D. student, Yuru Chang, M.S. student, Dustin Huff, Biological Scientist, Austyn Sanches, undergraduate studen
Dissemination Streams
The primary target audiences for this project are low-chill peaches producers in Florida, research and extension scientists, extension agents, and other stakeholders who are in business with low-chill stone fruit production. Our initial result communicated to growers, extension agents, researchers, and to the general public through following venues: -Extension publication "Thinning Florida Peaches for Larger Fruit" https://edis.ifas.ufl.edu/pdffiles/HS/HS132400.pdf -Developing grower email list STONEFRUIT-GROWERS-L@LISTS.UFL.EDU, which includes over 150 emails. -Web page: Stone Fruit at the University of Florida http://old-hos.ifas.ufl.edu/extension/stonefruit -Facebook: Stone Fruit at the University of Florida https://www.facebook.com/stonefruitUFIFAS/ - Blog: Operation Peaches in Florida https://ufstonefruit.wordpress.com/ - 2019 UF Annual Stone Fruit Workshop/Field Day, which over 140 clienteles joined the field day
Next Reporting Steps
The next setp of the projet is to provide the Florida low-chill peach producers with an alternative management procedure to overcome the most limiting factor in Florida peach production, "increasing fruit size," while maintaining fruit quality, utilizing following objectives: 1) Determine the influence of fruit location within the canopy on fruit size and quality. We will find which part of the canopy (bottom, mid, top) and which side (N, S, E, W) of the tree can deliver the most marketable fruit with an optimum size. If proven, growers would be able to localize flower buds or fruitlets in the right spots by their pruning and thinning practices. 2) Identify PGR approaches to enhance fruit size in low-chill peaches. PGRs will be applied after full bloom and before pit hardening. Other PGRs will be applied before pit hardening and after pit hardening to enhance cell division or extension, respectively. Fruit quality will also be monitored. 3) Provide resources for grower training and education and develop a statewide roadshow to extend project lessons to growers (i.e., factsheet, field demonstration, orchard walk, and workshop). <br><br>
<br>What was accomplished under these goals? Fruit Szie:Larger fruit size of subtropical peach (Prunus Persica. L) has been a desirable trait since production began. The fruit development period (FDP) of UF early ripening cultivars is as short as 60-90 days (Sarkhosh et al., 2018). Growers can take advantages of an early market window, but also face the problem of small fruit size because of the short FDP. Fruit thinning has been suggested as an effective method to increase fruit size (Costa & Vizzotto, 2010). Research on other crops has shown that fruit thinning can improve fruit size in apple, citrus, nectarines, and other crops (Guardiola et al., 2000; Schupp et al., 2008; Sharma & Shylla, 2017). So far, is fruit thinning important for peach juice production industry is still unclear. Therefore, the objective of this study was to assess the effect of peach fruit thinning on fresh fruit marketing and fruit juice producing and give more particular and useful suggestions to growers under different circumstances. Tree Nutrition: In the last decades rootstocks brought about a revolution in fruit growing, completely changing the shape and methods of cultivation of fruit orchards. The impact of the use of efficient rootstock on optimum fruit quality and yield have been well documented during the recent years (Fallahi et al., 2002; Amiri and Fallahi, 2009). The knowledge of seasonal variation in leaf nutrient concentrations is necessary in order to understand the physiology of peach nutrition and is also helpful in the interpretation of leaf analysis. More efficient rootstocks or plants, in terms of nutrient absorption and translocation, can enable the reduction in the amounts of fertilizers applied, without impairing fruit production and quality. Hence, understanding the relationships between the key physiological (growth, yield, fruit quality etc.), and physical (graft union repair, water usage and transport, hormones, nutrition) aspects mediated by the rootstock is important for the growth of high quality and commercially attractive fruit production (Koepke and Dhingra, 2013). The relationships between different rootstocks and differences in leaf nutrient levels have been documented in pear (North and Cook, 2008), apple (Kviklys et al., 2012), mango (Duran-Zuazo et al., 2005) and other trees. In this study, we hypothesized that rootstock genotypes with contrasting growth behavior would also influence growth, and leaf nutrient concentrations of peach cv. UFsun. Given that the rootstocks are unlike genotypes and may modify growth, fruit production and leaf mineral composition, therefore, the present study was aimed to evaluate the effect of rootstocks on leaf mineral composition of peach cv. UFsun. Hence, we hypothesized that rootstock genotypes with contrasting growth behavior would also influence growth, and leaf nutrient concentrations of peach cv. UFsun. This study aimed to investigate the differences of nutrient concentrations among rootstocks grown in the same conditions. The other goal of this experiment was determining seasonal variations of leaf nutrient concentrations to define nutrient needs related to growing period. <br><br><b>Publications</b><br>
Target Audience
The primary target audiences for this project are low-chill peaches producers in Florida, research and extension scientists, extension agents, and other stakeholders who are in business with low-chill stone fruit production. Our initial result communicated to growers, extension agents, researchers, and to the general public through following venues: -Extension publication "Thinning Florida Peaches for Larger Fruit" https://edis.ifas.ufl.edu/pdffiles/HS/HS132400.pdf -Developing grower email list STONEFRUIT-GROWERS-L@LISTS.UFL.EDU, which includes over 150 emails. -Web page: Stone Fruit at the University of Florida http://old-hos.ifas.ufl.edu/extension/stonefruit -Facebook: Stone Fruit at the University of Florida https://www.facebook.com/stonefruitUFIFAS/ - Blog: Operation Peaches in Florida https://ufstonefruit.wordpress.com/ - 2018 Unuversity of FloridaAnnual Stone Fruit Workshop/Field Day, which over 130 clienteles joined the field day.
Changes / Problems
Nothing Reported
Training & Professional Development
Shirin Shahkoomahally, Ph.D. student, Yuru Chang, M.S. student, Dustin Huff, Biological Scientist, Austyn Sanches, undergraduate student
Dissemination Streams
The primary target audiences for this project are low-chill peaches producers in Florida, research and extension scientists, extension agents, and other stakeholders who are in business with low-chill stone fruit production. Our initial result communicated to growers, extension agents, researchers, and to the general public through following venues: -Extension publication "Thinning Florida Peaches for Larger Fruit" https://edis.ifas.ufl.edu/pdffiles/HS/HS132400.pdf -Developing grower email list STONEFRUIT-GROWERS-L@LISTS.UFL.EDU, which includes over 150 emails. -Web page: Stone Fruit at the University of Florida http://old-hos.ifas.ufl.edu/extension/stonefruit -Facebook: Stone Fruit at the University of Florida https://www.facebook.com/stonefruitUFIFAS/ - Blog: Operation Peaches in Florida https://ufstonefruit.wordpress.com/ - 2018 UF Annual Stone Fruit Workshop/Field Day, which over 130 clienteles joined the field day.
Next Reporting Steps
The next setp of the projet is to provide the Florida low-chill peach producers with an alternative management procedure to overcome the most limiting factor in Florida peach production, "increasing fruit size," while maintaining fruit quality, utilizing following objectives: 1) Determine the influence of fruit location within the canopy on fruit size and quality. We will find which part of the canopy (bottom, mid, top) and which side (N, S, E, W) of the tree can deliver the most marketable fruit with an optimum size. If proven, growers would be able to localize flower buds or fruitlets in the right spots by their pruning and thinning practices. 2) Identify PGR approaches to enhance fruit size in low-chill peaches. PGRs will be applied after full bloom and before pit hardening. Other PGRs will be applied before pit hardening and after pit hardening to enhance cell division or extension, respectively. Fruit quality will also be monitored. 3) Provide resources for grower training and education and develop a statewide roadshow to extend project lessons to growers (i.e., factsheet, field demonstration, orchard walk, and workshop). <br><br>
<br>What was accomplished under these goals? Achieving a satisfactory fruit size when producing low-chill peaches with a short fruit development period under Florida's subtropical climate is still a major limitation in marketing. In the last few years, low-chill peaches showed the potential to become an economically viable fruit crop in Florida, driven partly by the spread of citrus greening (HLB). These "low-chill" varieties of peaches do not require as much winter chilling to produce fruit as traditional peach varieties that are grown farther north. Peach trees require more work to maintain than citrus (pruning twice a year and manual thinning and harvesting), but they grow quickly into a harvestable crop. In 2018, a fruit-thinning experiment was conducted with 20 'UFSun' scions grafted onto 'Flordaguard' rootstock trees. Half of the trees were thinned to leave 6 to 8 inches between fruit and half were not thinned. In the first week of May 2018, five fruit from each quadrant (NE, SE, NW, and SW) were sampled, equivalent to twenty fruit from each tree (200 fruit samples per treatment). The results showed that thinning increased the fruit weight by 45% and improved fruit diameter by 14%. Figure shows that the average diameter of un-thinned fruit was not of marketable size. These data demonstrate that thinning is especially critical to enhance fruit size of peaches with a short FDP that ripen in April and early May. <br><br><b>Publications</b><br>