1. Please state project objectives and what work was done this quarter to address them: Objective 1: Destroy declining plant material with no direct use to the citrus industry to make space for Stage I and Stage II trials (Years 1 and 2).Since project planning and the beginning of the project period, several thousand citrus trees have been pushed and destroyed at CREC, a portion of which is for making space for Stage I and Stage II trials. Of these several thousand trees, approximately 1,000 trees were pushed and destroyed since the beginning of the project period. Hundreds of trees have been identified as being suitable for conservation, movement with the tree spade (or other means) and sourced for budwood. The nursery is aware of the need to collect and propagate uncertified budwood and we are waiting on the go-ahead from the nurserymen and -women to transfer budwood of the trees identified for conservation and consolidation to the nursery. The drone project has identified trees that should be targeted for consolidation and ground truthing these trees has been completed at two large blocks of Plant Improvement land. UFarm charges have conserved and saved all materials needed for data mining for tolerant genes and other variants. Objective 2: Conserve, move, consolidate, and propagate tolerant and resistant citrus trees to a centralized location. (Years 1 and 2).The block where consolidation will take place has been reserved for this purpose. We are awaiting the nursery’s go-ahead to propagate the material. Rootstocks have been selected. When the buds take, we will move forward with tree movement with tree spade and other means. We do not have possession of the tree spade. According to the contractor who is repairing it, the tree spade will be ready in two to three weeks. We are developing contingency plans if the nursery delays the budwood transfer. 2. Please state what work is anticipated for next quarter: We anticipate taking possession of the USDA-ARS tree spade from the contractor and transferring budwood to the nursery for propagation. We also anticipate removing thousands of citrus trees with no immediate value to the citrus industry to continue to make space for Stage I and II trials. 3. Please state budget status (underspend or overspend, and why): We are 1% underspent (15% time spent versus 14% funded expended) according to the UF/IFAS grants tracking system. The budget is underspent as we wait for the repairs of the tree spade. Once that payment is made to the contractor, we should be on track for spending. It was not anticipated for the tree spade repair to take more than three months.
1. Please state project objectives and what work was done this quarter to address them: The overall goal is to discover which of the seven (7) grapefruit scion and six (6) rootstock combinations planted in 41 blocks perform well under the endemic HLB disease pressure in Florida. The objectives are to 1) measure tree growth (using drone technology) and ratings of canopy thickness, yellowing, and HLB disease symptom severity, and 2) estimate fruit drop and tree yields as they come into production through preharvest fruit counts and measurement of fruit weight, size distribution and fruit quality from representative fruit samples. Work done: In November and December 2023, and January 2024 we continued with the fruit sampling for sizing and external and internal fruit quality analysis, to calculate fruit yield, plus the estimation of fruit drop by counting fruits on the tree and on the ground. Drone data collected in October was accessible in late November, which is still to be analyzed due to the volume of data to be exported. We have initial data for fruit quality and yield for the eight blocks that were confirmed as ready to harvest. Due to raining conditions in December, the Holidays and vacation time of team members, data collection has been extended into January and February 2024. We completed data collection of 75% of the blocks, and expect to finish it by early March.Preliminary data was presented to the Indian River Citrus League Board of Directors meeting on February 10th, 2024. 2. Please state what work is anticipated for next quarter: Next quarter we will have another round of drone data collection, plus field measurements of tree growth and HLB symptoms based on a quadrant-evaluation rating (disease index). 3. Please state budget status (underspend or overspend, and why): Spending generally on track – payroll was started in October with the start of field evaluations and fruit harvests and is running a little behind schedule. Expenses for half the drone measurements have been paid.
1. Please state project objectives and what work was done this quarter to address them: The purpose of this project is to generate non-transgenic HLB resistant Valencia and Hamlin sweet orange plants using CRISPR-Cas technology. Objective 1. Generate non-transgenic HLB resistant/tolerant Valencia and Hamlin sweet orange plants by mutation of HLB susceptibility genes. In total, six putative S genes were proposed to be edited and we have lately added more targets. Constructs needed for CRISPR genome editing are being made. Multiple edited lines were generated for ACD2 gene. However, further confirmation demonstrated none of them was biallelic/homozygous mutant. We are genenerating more lines for ACD2 and other target genes. To speed up the process, we have further optimized the transgene-free CRISPR genome editing using Cas12a/crRNA ribonucleoprotein. We have developed an efficient co-editing strategy for generating transgene-free, gene-edited plants via Agrobacterium-mediated transient expression of cytosine base editor (CBE)/gRNA-Cas12a/crRNA-GFP in planta. Specifically, CBE/gRNA was used to base edit the ALS gene to confer resistance to herbicide chlorsulfuron as a selection marker, which has no negative effects on plant phenotypes; Cas12a/crRNA was used for editing genes(s) of interest; GFP was used for selecting transgene-free transformants. Using this approach, transgene-free genome-edited plants can be relatively easily generated for citrus in the T0 generation. Whole genome sequencing further confirmed transgene-free and absence of off-target mutations in the edited plants. We are also using this strategy for genome editing of our target genes. This has been published by Nat. Plants (9, 15911597, 2023. https://doi.org/10.1038/s41477-023-01520-y). Among the 8 target genes, we have done transformation again on 5/18/23, 5/25/23, 6/25/23, 7/27/23, 8/17/23, 11/16/23, 12/07/23, 1/18/24. The transformants are under regeneration. Deep sequencing of the edited protoplasts showed a mutation rate of 16-78%. Two targets have near zero mutation rates. We are optimizing the guide RNA design. Some lines done in May 2023 are getting close to be micro-grafted.In addition, we have generated Ray Ruby embryogenic protoplasts which are being tested for efficacy of transformation, editing, and regeneration. Objective 2. Generate cisgenic genome modified Valencia and Hamlin sweet orange plants by knock-in the gene encoding MaSAMP from Microcitrus. We are optimizing the knock-in method using the CRISPR technology. We have made some progress in knock-in methodology using non-transgenic approach. We have conducted multiple transformations useing the developed method for knockin with MaSAMP. The protoplasts were being regenerated.We have demonstrated the knock-in works using GFP as an insert. We have conducted knock-in for MaSAMP on 5/18/23, 8/17/23, 11/16/23, 12/07/23, 1/18/24 which are under regeneration. 2. Please state what work is anticipated for next quarter:To generate more genome edited lines for ACD2 and other target genes using both RNP method and the co-editing method. Conductu regeneration for all the transformants. Conduct micro-grafting for shoots when ready.3. Please state budget status (underspend or overspend, and why):On schedule.
1. Please state project objectives and what work was done this quarter to address them: Objective 1: Assess rootstock propagation method and rootstock cultivar effects on growth, health, and productivity of grafted Valencia trees during the early production years (years 4-6 after planting) in two commercial citrus production environments. Objective 2: Assess rootstock propagation method effect on tree performance, root architectures and uprooting resistance of Valencia trees after 5 years of growth.We continued to monitor the trees. Rhizotron analysis continued. CLas analyses are in progress. 2. Please state what work is anticipated for next quarter:We will collect leaves for CLas analysis, conduct disease ratings, take rhizotron pictures, and continue with all data and lab analyses. We will also prepare for the harvest. 3. Please state budget status (underspend or overspend, and why): Budget status is on track.
1. Please state project objectives and what work was done this quarter to address them:This quarter, Project #21-025 continued its focused efforts on developing HLB-resistant and improved citrus cultivars to combat the devastating effects of HLB on the Florida citrus industry. The goal remains to provide sustainable solutions to combat HLB, safeguard the citrus industry, and conduct resarch that supports economic citrus production. During this quarter, the primary emphasis was on data collecttion, progress on new BRS permitting and renewal of existing BRS permits. The permits were submitted are under review by BRS staff. There has been an exchange of emails throughtout the permit process and updates continue to be made as the permit continue through the pipeline for approval. In addition data was collected on USDA field material. Fruit and leaf samples were sent to Dr. Mou at UF for deeper analyisis.2. Please state what work is anticipated for next quarter:We are expecting approval of the permits sent to USDA BRS any day now. These permits will allow for the continued research and evlauation of plant materials at this site. In addition, there is a new BRS permit to test new constructs developed by the Shatters group at USDA to approved for planting in the field. Upon permit approval propagation of these materilas will begin with the goal of planting in the fall of 2024 or spring of 20253. Please state budget status (underspend or overspend, and why):The project experienced a slight underspend primarily due to complications in hiring USDA personnel and historical underspend trends assoicated with this project. The 6 month extension granted by CRDF has allowed us to catch up on spend with the tehcnition The technition on this project is currently budgeted and continuously working on permitting assoicated improvment of this block for the USDA and cooperators.4. Please show all potential commercialization products resulting from this research, and the status of each:The project has shown promising results in identifying HLB-resistant transgenic citrus cultivars. Some of the candidate materials display a high likelihood of being suitable for commercial citrus production. These HLB-tolerant cultivars could become valuable assets to the citrus industry, providing a sustainable solution to combat the devastating impact of HLB. Other materials may serve as important breeding parents for further improvement in HLB resistance and other commercially significant traits. Materials from Dr. Mou’s trees were submitted to FL DPI, the first step towards commercialization as certified budwood.
1. Please state project objectives and what work was done this quarter to address them: Objective 1: Production of interstock trees for evaluation in grower plots Interstock grafts have been produced on all of the rootstocks. However, the project has had minor setback due to severe thrip infestation that slowed down the growth of the trees. Currently most have flushed and are growing vigorously, and should be ready for the final propagation of the top scion (Sweet orange and grapefruit) in early spring. 2. Please state what work is anticipated for next quarter: All rootstock liners have been stick grafted with the HLB tolerant interstocks. The failed lines will be redone in this quarter for growth. 3. Please state budget status (underspend or overspend, and why): We are on track with the budget spending as funds have been committed for plant propagation.
1. Please state project objectives and what work was done this quarter to address them: Objective 1: Study the changes in the reactive oxygen species (ROS) and investigate the correlation between ROS accumulation, sucrose levels and callose deposition in early season sweet oranges Infected trees were created by two combined methods – grafting and psyllid exposure. Infection rates are being determined currently. The polar metabolite, stored volatiles, released volatiles from leaves, stomata number and size, phenolic compounds, ROS, Nitric oxide, and starch content were measured in Parson Brown, Roble, and Hamlin, all on swingle and under controlled conditions and randomly organized. Draft of a manuscript will be ready by early 2024. Objective 2: Quantify fruit drop and canopy yield efficiency in Parson Brown as compared to Hamlin. Understand the underlying mechanism of better fruit retention and yield efficiency in Parson Brown as compared to Hamlin. In this quarter we have performed three monthly sampling for FDF of Parson brown and Hamlin fruit. We also collected the abscission zone and peel from both varieties and currently analyzing them for sugar content, phytohormones, and oxidative stress markers. Objective 3: Determine the mechanism underpinning the tolerance of Parson Brown to HLB by leaf volatiles and non-volatile metabolite analysis using GC-MS. Comparison in responses after infection will be measured in 2024. Responses will include but not be restricted to, symptoms, metabolic changes including hormones, and cellular responses including start accumulation and callose deposition. In addition to measuring the bacterial titer using a plasmid with a single copy unique CLas sequence for absolute cell quantification. Objective 4: Evaluate other early season sweet orangesLeaf samples have been collected from a Roble sweet orange grove in Zephyrhills. Additionally, samples from several survivor trees from a grove in Lake County have been collected. We have analysed the HLB status of these trees and the biochemical profile of the leaf samples. 2. Please state what work is anticipated for next quarter: Molecular and biochemical analysis of the HLB infected trees will be initiated. We will also collct samples in the fall from Roble and Hamlin trees 3. Please state budget status (underspend or overspend, and why): We are on track with the budget. A postdoc has been hired to work on several of the parameters in this project from the second quarter.
1. Please state project objectives and what work was done this quarter to address them: The overall goal is to discover which of the seven (7) grapefruit scion and six (6) rootstock combinations planted in 41 blocks perform well under the endemic HLB disease pressure in Florida. The objectives are to 1) measure tree growth (using drone technology) and ratings of canopy thickness, yellowing, and HLB disease symptom severity, and 2) estimate fruit drop and tree yields as they come into production through preharvest fruit counts and measurement of fruit weight, size distribution and fruit quality from representative fruit samples. Work done: Per the project timeline, Aerobotics collected drone measurements of all experimental blocks in October, but one due to the presence of ICPs on the plants. The ICPs have now been removed and will be flown over by the drone. The drone data is now available for further analysis. In late October we started evaluating blocks: collecting fruit samples for sizing and external and internal fruit quality analysis, to calculate fruit yield. Concomitantly, we are counting fruits on the tree and on the ground (estimating fruit drop percentage), plus rating HLB symptoms based on a quadrant-evaluation rating (disease index). Fruit count and disease index are performed by the same person in all the blocks. We antecipate to finish fruit sampling and juice analysis in December. 2. Please state what work is anticipated for next quarter:Next quarter we will finish the first round of measurements/sampling all the blocks, will conduct another round of tree measurements (via drone), and will start another round of block evaluations: measuring disease index, documenting tree growth and health with photographs with a height pole as reference. 3. Please state budget status (underspend or overspend, and why): Spending on track – payroll was started in October with the start of field evaluations and fruit harvests with heavy draw-down continuig during block visits and evaluations through April. Expense for drone measurements have not yet been incurred – the invoice will be sent by the mid-month following data collection.
1. Please state project objectives and what work was done this quarter to address them: Knocking out disease susceptibility genes (S genes) has resulted in broad disease resistance in multiple crops. The bottleneck to using CRISPR for engineering HLB resistance in citrus has been the lack of suitable and validated gene targets. Identifying suitable gene targets has been the most urgent task for achieving HLB resistance through gene editing. We are the first group in the world that have knocked out two S genes, DMR6 and SWEET1, in HLB-susceptible `Duncan’ grapefruit and produced dmr6 and sweet1 mutants. The objectives of this project are to evaluate the resistance of four `Duncan’ mutants’ after graft inoculation (Objective 1a) and exposure to infected Asian citrus psyllids (ACP) (Objective 1b,) and to assess potential side effects of these mutations on citrus plant growth and morphology (Objective 2). The overall goal of this project is to determine the effectiveness of editing DMR6 and SWEET1 for engineering HLB resistance in citrus. Experiment 1 is being conducted to achieve Objective 1a. Four `Duncan’ mutants and one control wildtype line were grafted onto HLB-free sour orange rootstock in two batches. The first batch of clonal plants were graft-inoculated with CLas-positive buds or CLas-free buds (mock inoculation) on June 17th, 2023, resulting in 29 graft-inoculated plants and 10 mock-inoculated plants. These plants have been grown in a temperature-controlled greenhouse. Data on plant height, trunk diameter below and above graft union, HLB symptoms, and CLas titer were collected on June 6th (before inoculation) and September 21st, 2023 (3 months post inoculation). The Ct value of these mutants and wildtype was approximately 40, indicating undetectable CLas in these inoculated plants. The second batch of clonal plants (total 34, with 4 to 8 per mutant) were propagated onto sour orange on July 24th, 2023. These plants have grown to a height of 5 to 12 inches. Experiment 2 and Experiment 3 are being conducted for Objective 1b and 2, respectively. These experiments require approximately 20 clonal plants of similar stem diameters for each mutant or wildtype line. To produce the required clonal plants for these objectives, 50 to 75 cuttings were taken from each mutant stock plant and stuck into potting mix in early July 2023. The cuttings were rooted under an intermittent misting system in a secure greenhouse for 3 months. For each mutant, six to 37 cuttings have rooted and produced new shoots. To produce additional clonal plants for Objective 1b and 2, another batch of cuttings were taken on November 3, 2023. These cuttings are being rooted in Oasis Rootcubes. 2. Please state what work is anticipated for next quarter: Objective 1a (Experiment 1) -1st batch of inoculated plants: Since this batch of inoculated mutant and wildtype plants have not shown any HLB symptoms or CLas titer 5 months after inoculation, we suspect that the graft inoculation with hot citrus buds might not have provided sufficient CLas inoculum. We plan to re-inoculate these plants using a different method, i.e., by exposing the plants to infected ACP. These plants will be trimmed to induce a new flush of tender shoots for infected ACP feeding. Subsequently, leaf samples will be collected, DNA will be extracted, and qRT-PCR will be run to determine CLas titers in these mutants. Data on plant height, trunk diameter, HLB symptom will be collected as well. Objective 1a (Experiment 1) – 2nd batch of clonal plants: As the graft inoculation did not result in sufficient inoculum in the 1st batch of inoculated plants, we propose to inoculate the 2nd batch of clonal plants by 1-2 weeks’ feeding of infected ACP. 1-2 weeks. Subsequently, ACP will be killed, and the plants will be grown in a temperature-controlled greenhouse. Data on plant growth, trunk diameter, HLB symptom, and CLas titer will be collected 3 months post inoculation. Objective 1b (Experiment 2): The focus will be on producing a sufficient number of rooted cuttings with actively growing shoots for all mutant lines. Rooted cuttings will be pushed to grow rapidly for ACP inoculation near the end of the second quarter of this project, as described above.Objective 2 (Experiment 3): When mutant cuttings are fully rooted, they will be potted up in containers and grown in a secure greenhouse at CREC. Plant growth and leaf and shoot morphology of mutants will be monitored closely and compared with the wildtype to determine potential side effects from the edited S genes. 3. Please state budget status (underspend or overspend, and why): The total spendings by far add to $4,190.75, about 4.2% of the total budget. This is below the expected spending for the first quarter of the project. The primary reason was the difficulty we experienced in propagating the mutants and the wildtype to produce clonal plants for Objective 1b and 2 during the hot summer months. Without a sufficient number of clonal plants, the planned CLas inoculation, DNA extraction, qRT-PCR, and horticultural experiments had to be postponed to the 2nd quarter of the project.
1. Please state project objectives and what work was done this quarter to address them: The purpose of this project is to generate non-transgenic HLB resistant Valencia and Hamlin sweet orange plants using CRISPR-Cas technology. Objective 1. Generate non-transgenic HLB resistant/tolerant Valencia and Hamlin sweet orange plants by mutation of HLB susceptibility genes. In total, six putative S genes were proposed to be edited and we have lately added more targets. Constructs needed for CRISPR genome editing are being made. Multiple edited lines were generated for ACD2 gene. However, further confirmation demonstrated none of them was biallelic/homozygous mutant. We are genenerating more lines for ACD2 and other target genes. To speed up the process, we have further optimized the transgene-free CRISPR genome editing using Cas12a/crRNA ribonucleoprotein. We have developed an efficient co-editing strategy for generating transgene-free, gene-edited plants via Agrobacterium-mediated transient expression of cytosine base editor (CBE)/gRNA-Cas12a/crRNA-GFP in planta. Specifically, CBE/gRNA was used to base edit the ALS gene to confer resistance to herbicide chlorsulfuron as a selection marker, which has no negative effects on plant phenotypes; Cas12a/crRNA was used for editing genes(s) of interest; GFP was used for selecting transgene-free transformants. Using this approach, transgene-free genome-edited plants can be relatively easily generated for citrus in the T0 generation. Whole genome sequencing further confirmed transgene-free and absence of off-target mutations in the edited plants. We are also using this strategy for genome editing of our target genes. This has been published by Nat. Plants (9, 15911597, 2023. https://doi.org/10.1038/s41477-023-01520-y). Among the 8 target genes, we have done transformation again on 5/18, 5/25, 6/25, 7/27, and 8/17. The transformants are under regeneration. Objective 2. Generate cisgenic genome modified Valencia and Hamlin sweet orange plants by knock-in the gene encoding MaSAMP from Microcitrus. We are optimizing the knock-in method using the CRISPR technology. We have made some progress in knock-in methodology using non-transgenic approach. We have conducted multiple transformations useing the developed method for knockin with MaSAMP. The protoplasts were being regenerated.We have demonstrated the knock-in works using GFP as an insert. We have conducted knock-in for MaSAMP on 5/18, and 8/17 which are under regeneration. 2. Please state what work is anticipated for next quarter:To generate more genome edited lines for ACD2 and other target genes using both RNP method and the co-editing method. Conductu regeneration for all the transformants. 3. Please state budget status (underspend or overspend, and why):On schedule.
Objective 1. Collect field performance data from replicated rootstock field trials and release new rootstock cultivars as justified by superior performance in multiyear field trials.Collect field performance data. Thirty-two USDA replicated rootstock trials are active. For the current quarter, canopy health was collected from all trials. Cropping and fruit quality data was collected from two early mandarin rootstock trials, and two lemon rootstock trials. Juice analysis of frozen samples continued from trials for the 2022-23 season. A new auto-titrator and spectrophotometer for use in fruit quality analysis were purchased from base USDA funds, and will greatly accelerate and improve the evaluation of fruit quality in rootstock trials.During this quarter, SSR assessment of trueness-to-type from seed was completed for the SuperSour rootstocks that are available now and will be released this year. This information on trueness-to-type from seed will be published shortly after the official release of the two new rootstocks. Additional work on trueness-to-type assessment and salinity tolerance of new rootstocks was continued.Release of new rootstocks. New rootstocks will be officially released by USDA for commercial use when justified by superior performance in multi-year replicated field trials. The most promising USDA rootstock selections are provided to the FDACS-DPI program for shoot tip grafting and disease testing in advance of potential release. The two new USDA rootstocks, US SuperSour 4 and US SuperSour 5 were released by USDA on September 5th, 2023, and are already clean and available in the DPI program to commercial nurseries. Four other promising new USDA rootstocks were provided to DPI for STG and testing this quarter, in preparation for possible release in future years.Objective 2. Create hybrid rootstocks that combine germplasm from parental material with good rootstock traits and HLB tolerance, propagate the most promising of these hybrids, and establish replicated field trials with commercial scions.Create hybrids. Selected new crosses were completed in spring 2023, and seed extracted this quarter. About 230 hybrid seedlings from high priority crosses will be grown in the spring for preliminary evaluation and further testing.Propagate hybrids. Trees for two new stage 2 rootstock trials with 33 advanced selection SuperSour rootstocks with Valencia scion continue growing in the nursery, with a plan for field planting in summer 2024.Establish replicated field trials. One new replicated field trial with a new high quality mandarin scion on 17 rootstocks was established this quarter at the Whitmore farm in Lake County.Tree care in trials. Periodic care was applied in the 32 field trials to maintain tree health and productivity, and manage weeds. Two young rootstock trials are being grown with IPCs. One rootstock trial is being used for a comparison of tree performance of different rootstocks with and without OTC injection.2. Please state what work is anticipated for next quarter:For the coming quarter, work will focus on collection of 2023-24 season yield and fruit quality data from trials with Hamlin scion, continuing propagation of trees for future trials, and care of existing trees in trials. Data analysis of tree performance in the 32 trials is underway, to evaluate SuperSour candidates for official release in 2025-26, and compare performance of those commercially available. Cooperative work continues to evaluate USDA rootstocks for tolerance/resistance to sting nematode, citrus nematode, salinity, cold hardiness, and other traits.3. Please state budget status (underspend or overspend, and why):The budget is on schedule for spending all funds by the end of the currently funded year. One employee left the program, and a recruitment is underway to take on those duties. Work is progressing as planned.
1. Please state project objectives and what work was done this quarter to address them: Objective 1: Assess rootstock propagation method and rootstock cultivar effects on growth, health, and productivity of grafted Valencia trees during the early production years (years 4-6 after planting) in two commercial citrus production environments. Objective 2: Assess rootstock propagation method effect on tree performance, root architectures and uprooting resistance of Valencia trees after 5 years of growth.Leaves were collected for nutrient analysis. Roots were collected for root length analysis. Tree size measurements were conducted. Rhizotron analysis continued. CLas analyses are in progress. All trees in one of the commercial sites were injected with OTC by the grower collaborator this year. 2. Please state what work is anticipated for next quarter: Lab analyses and data analyses will continue. Tree health will be monitored. 3. Please state budget status (underspend or overspend, and why): Budget status is on track.
1. Please state project objectives and what work was done this quarter to address them: This quarter, Project #21-025 continued its dedicated efforts towards developing HLB-resistant and improved citrus cultivars to mitigate the detrimental impact of HLB on the Florida citrus industry. The project employed both transgenic and non-transgenic approaches and conducted experiments at the secure field site of the USDA/ARS Picos Research Farm. The primary focus remained on collecting data from ongoing field trials for various HLB-resistant candidates. To ensure realistic evaluations of candidates’ resistance, the test site received necessary horticultural care and maintained exposure to HLB and psyllids. Additionally, the team adhered rto BRS permits and underwent inspections to uphold regulatory compliance. A significant milestone during this quarter was the hosting of a field day, where researchers and stakeholders were provided with insights into successful trial materials and the data collection processes. Moreover, signage and field markers were updated to enhance collaborator ease and streamline documentation processes. There were over 60 in attendance at this first field day event. 2. Please state what work is anticipated for next quarter:Efforts will also focus on updating transgenic field markers signage and labeling to ensure compliance. Additionally, the project aims to submit a permit to BRS for additional planting in late summer and early fall, enabling further research expansion (Material from Dr. Robert Shatters). Data collection on active trials will continue, with allocated labor for monitoring and permitting to ensure smooth progress. 3. Please state budget status (underspend or overspend, and why):The project experienced a slight underspend primarily due to complications in hiring USDA personnel and historical underspend trends assoicated with this project. The technition on this project is currently budgeted and continuously working on permitting assoicated improvment of this block for the USDA and cooperators. 4. Please show all potential commercialization products resulting from this research, and the status of each:The research conducted under Project #21-025 has yielded promising results in identifying HLB-resistant transgenic and non-transgenic citrus cultivars. Some of these materials show potential for commercial citrus production, while others may serve as breeding parents for further improvement in HLB resistance and other commercially significant traits. Data gathered from the field trials will continue to guide the project in advancing the most promising materials to larger trials, ultimately contributing to the development of commercially viable HLB-resistant citrus varieties and safeguarding the Florida citrus industry’s future.
1. Please state project objectives and what work was done this quarter to address them: Objective 1: Production of interstock trees for evaluation in grower plots Interstock grafts have been produced on most of the rootstocks. Some of the rootstock liners growing in the greenhouse were damaged due to a hard to control thrip infestation in the greenhouse which led to malformed leaves and shoots. We have controlled the greenhouse infestation but the grafting work has been slightly delayed due to this issue. It is anticipated that all interstock grafting will be completed in the next quarter. 2. Please state what work is anticipated for next quarter: All rootstock liners should be stick grafted with the HLB tolerant interstocks in the third quarter of this project. 3. Please state budget status (underspend or overspend, and why): We are on track with the budget spending as funds have been committed for plant propagation.
1. Please state project objectives and what work was done this quarter to address them: The overall goal is to discover which of the seven (7) grapefruit scion and six (6) rootstock combinations planted in 41 blocks perform well under the endemic HLB disease pressure in Florida. The objectives are to 1) measure tree growth (using drone technology) and ratings of canopy thickness, yellowing, and HLB disease symptom severity, and 2) estimate fruit drop and tree yields as they come into production through preharvest fruit counts and measurement of fruit weight, size distribution and fruit quality from representative fruit samples. Work done: Per the project timeline, we have been preparing for September and October grove visits and tree and fruit measurements. We have also developed a contract with Aerobotics to collect drone measurements on all experimental blocks in September and October of this year. 2. Please state what work is anticipated for next quarter: Next quarter will be extremely busy conducting tree measurements (via drone), taking tree measuremnts and, for trees with fruit production, record fruit numbers on sample trees (not including buffer trees) and raking underneath the trees to later measure fruit drop. 3. Please state budget status (underspend or overspend, and why): Currently underspending because no field work yet underway this quarter. Heavy use of personelle (and expenses) begin in September (next quarter) and wil continue throughout the winter. In addition, expense for drone measurements have not yet been incurred.
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