2005 Annual Report 1.What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter? Profitable pecan husbandry is a major problem for U.S. pecan farmers and to those who process, use, and consume pecans. This is largely due to:. 1)highly variable nut production (termed alternate bearing);. 2)premature loss of fruit; and. 3)disease related crop losses and associated cost of disease control. Failure to find adequate solutions to these biological problems will result in a serious decline in both quantity and quality of domestically produced pecans available to U.S. citizens and will also adversely affect the economic viability of pecan farm families and related operations. This work is therefore highly relevant to U.S. farm families engaged in pecan farming, their communities, and to the processors, users, and consumers of pecan nuts. Agriculture will benefit from improved cultural tools and management strategies for pecan with ramifications for many other agricultural crops. These will be key components of integrated, profitable, and environmentally-friendly production systems that conserve natural resources. The general approach of this project is to devise environmentally sound and cost-effective husbandry strategies for pecan farming enterprises. This is to be attained by addressing the following objectives:. 1)development of tools and approaches facilitating environmentally sound and profitable cultivation via acquisition of greater understanding of key processes regulating alternate bearing, nutmeat yield and crop retention, and. 2)development of improved disease control strategies while minimizing pesticide usage. The specific approaches being utilized to resolve these problems are:. 1)identification of alternate bearing regulatory processes within the tree;. 2)modification of alternate bearing via timely usage of gibberellins or inhibitors;. 3)development of hedge pruning and topping as a tool for moderating alternate bearing and for increasing orchard efficiency;. 4)development of ultra high density hedge pruning of early flowering and prolific varieties;. 5)development of a chemical fruit thinning strategy;. 6)development of a strategy to reduce water-stage fruit-split;. 7)development of a means of reducing premature germination of nuts (vivipary);. 8)identification of the cause of mouse-ear replant disease and development of strategies to prevent the disease or disorder;. 9)improved control strategies for foliar and fruit scab disease; 10) improved control strategies for shuck decline disease; and 11) development of strategies to prevent fruit loss due to shuck and kernel rot. The research to be undertaken falls under the National Programs 305 and 303. For NP-305 it addresses Component I: Integrated Production Systems; and for NP-303 it addresses Component III: Cultural Controls. 2.List the milestones (indicators of progress) from your Project Plan. Year 1 (FY 2005): 1. Resolve the basic alternate bearing unit and identification of the optimum leaf:fruit ratio for kernel filling. 2. Continuation of field studies to assess the population of candidate growth regulators used on other crops for their potential as regulators of flowering in pecan. 3. Continuation of previously initiated mechanical pruning studies to resolve issues pertaining to key components necessary for the development of optimal hedge pruning strategies; study includes investigation of how the pruning strategy influences the light environment of the tree and how the tree responds to the pruning strategy. 4. Continuation of a field study to evaluate the feasibility of the pecan industry adopting “high density hedge-row pruning,” with the study addressing variety response and technique. 5. Continuation of observations on conditions that trigger and intensify water-stage fruit split, with the role of potassium, nickel, copper, boron, and chlorine nutrition being evaluated. 6. Evaluate via field studies the influence of factors that act to either increase or decrease the pre-harvest germination of seeds while still on the tree, with emphasis being on Mo. 7. Transfer technology regarding nickel deficiency in pecan and other crops, plus continue with study of the physiological role of nickel in pecan and other species, with emphasis on how Ni deficiency influences physiological pathways and enzyme activation. 8. Screen the efficacy of various nutritional factors for their role in either increasing or reducing fruit-set. 9. Continuation of field studies to evaluate effects of the micro-nutrient Ni on enhanced efficacy of fungicide applications to control pecan scab and other production limiting diseases. 10. Evaluate the control recommendations previously developed for the control of Phytophthora shuck and kernel rot in middle Georgia orchards known to harbor the disease. 11. Continuation of shuck decline investigations to determine pathogens involved, favorable conditions for disease development, and remedies to reduce or eliminate this production limiting complex. Year 2 (FY 2006) 1. Explore in greater detail the role of the internal dormant season nitrogen pool and its regulation of flowering and alternate bearing and characterize the mobilized forms of nitrogen. 2. Continuation of field studies evaluating likely candidate substances for control of flowering and alternate bearing via promoters and inhibitors of these physiological processes. 3. Continuation of previously initiated mechanical pruning studies to resolve issues pertaining to key components necessary for the development of optimal hedge pruning strategies; study includes investigation of how the pruning strategy influences the light environment of the tree and how the tree responds to the pruning strategy. 4. Continuation of a field study to evaluate the feasibility of the pecan industry adopting “high density hedge-row pruning,” with the study addressing variety response and technique. 5. Continuation of field observations on conditions that trigger and intensify water-stage fruit split, with the role of potassium, nickel, copper, boron, and chlorine nutrition being evaluated. 6. Evaluate via field studies the influence of factors that act to either increase or decrease the pre-harvest germination of seeds while still on the tree, with emphasis being on nitrogen. 7. Assess the role on nickel as a key co-factor in the activation of one or more key plant enzymes. 8. Screen the efficacy of various plant growth regulators for their role in either increasing or reducing fruit-set. 9. Continued field evaluation of the enhanced effect of fungicides by the micro-nutrient Ni on pecan scab development and increased quality of the treated pecan crop. 10. Continued evaluation of control measures for Phytophthora shuck and kernel rot, continue disease ratings, determine the effectiveness of the control measures. 11. Continuation of shuck decline investigations and evaluation of remedies to reduce or eliminate this production limiting complex. Year 3 (2007) 1. Continuation of studies to better understand the role of carbohydrates and nitrogen in flowering and alternate bearing. 2. Continuation of field studies evaluating likely candidate substances, with emphasis on efforts to identify proper concentration and timing so as to enable development of a practical field strategy. 3. Continuation of previously initiated mechanical pruning studies to resolve issues pertaining to key components necessary for the development of optimal hedge pruning strategies; study includes investigation of how the pruning strategy influences the light environment of the tree and how the tree responds to the pruning strategy. 4. Continuation of a field study to evaluate the feasibility of the pecan industry adopting “high density hedge-row pruning,” with the study addressing variety response and technique. 5. Continuation of field observations on conditions that trigger and intensify water-stage fruit split, with the role of potassium, nickel, copper, boron, and chlorine nutrition being evaluated. 6. Evaluate via field studies the influence of factors that act to either increase or decrease the pre-harvest germination of seeds while still on the tree, with emphasis being on ABA. 7. Identify and characterize nickel associated enzymes. 8. Field evaluation strategies that provide the greatest efficacy regarding efforts to retain or to remove flowers so as to ensure control of fruit-set and alternate bearing. 9. Continued field evaluation of the enhanced effect of fungicides by the micro-nutrient Ni on pecan scab development and increased quality of the treated pecan crop. 10. Continued evaluation of control measures for Phytophthora shuck and kernel rot, continue disease ratings, determine the effectiveness of the control measures. 11. Continuation of shuck decline investigations and evaluation of remedies to reduce or eliminate this production limiting complex. Year 4 (2008) 1. Summarize findings, assimilate into existing knowledge, and present a new conceptual tool to farmers for managing pecan orchards to minimize alternate bearing and to researchers for revising the theory of alternate bearing in pecan. 2. The identified management protocol will be further field evaluated, and relevant efforts initiated to transfer the technology to farmers, and EPA registrations pursued if needed. 3. Summarize and integrate what has been learned about pruning of pecan, especially how the tree responds in terms of alternate bearing and flowering, and formulate guideline principles and recommended protocols for successful usage of mechanical pruning as a tool for use in pecan husbandry, and transfer these to farmers and extension specialists. 4. Transfer technology to farmers and extension specialists regarding the feasibility and approach pertaining to the adoption a new husbandry approach involving the usage of “high density hedge-row pruning”. 5. Summarize finding regarding the influence of nutrient element nutrition management on incidence and severity of water-stage fruit-split and transfer guidelines on what can be done via water and nutrient management to minimize economic losses to this malady. 6. Transfer findings regarding the influence of nutritional status and hormonal status on causing or reducing pre-harvest germination. 7. Transfer technology to farmers and extension specialists regarding the critical role of nickel nutrition and communicate regarding practices that disrupt nickel associated physiological processes; plus communicate to the scientific community a better understanding of the role of Ni in plant nutritional physiology. 8. Transfer to farmers and extension specialists guidelines and protocols as to how nutritional and/or phytohormones can be used to manipulate fruit-set. 9. Summarize findings concerning enhanced fungicide efficacy with Ni foliar application for the control of pecan scab and transfer the technology to industry, farmers and extension specialists for disease control strategies. 10. Transfer technology to farmers and extension specialists regarding control of Phytophthora shuck and kernel rot using orchard history, scouting, environmental conditions and selection and application of fungicides as criteria for control decisions and strategies. 11. Summarize findings concerning shuck decline, pathogens involved, favorable conditions for disease development and remedies to reduce or eliminate this production limiting complex and transfer the technology to farmers and extension specialists. 4a.What was the single most significant accomplishment this past year? The study of nickel nutrition revealed that this nano-nutrient plays a far more important role in plants than previously recognized. Nickel deficiency was also found to be more common than generally recognized and is contributing to yield losses associated with flowering, alternate bearing and disease resistance. This knowledge will impact other crops and will increase profitability of many different crops. 4b.List other significant accomplishments, if any. Certain micronutrients and plant growth regulators were identified that can be used to improve flower retention, thus minimizing fruit abortions and pecan crop losses. Refinement of the approach will provide pecan farmers a tool for increasing crop-set and yields. Collaborative research produced the first genetic linkage maps of pecan, thus providing linkage markers useful in the selection of genetically superior types in efforts to produce superior cultivars for farmers. 4c.List any significant activities that support special target populations. None. 4d.Progress report. This report serves to document research conducted under a specific cooperative agreement between ARS and New Mexico State University. Additional details of research can be found in the report for the parent CRIS 6606-21220-009-00D Pecan Horticulture and Disease Research. Progress to date: a) identified improved control strategies for pecan aphids and has confirmed that pecan aphids can greatly reduce yield and orchard profitability; b) determined that pecan crops require at least 5 acre-feet of water; c) determined that late summer nitrogen applications confer a positive benefit to pecan production and that excessive application of nitrogen to pecan in certain southwestern soils is likely resulting in movement of nitrogen beyond the rooting zone of trees, thus serving to revise nitrogen management strategies; and d) identification of the partial gene sequence of root-knot nematodes attacking pecan. 5.Describe the major accomplishments over the life of the project, including their predicted or actual impact. The discovery of the existence of field-level nickel deficiency in pecan and many other crops, elevated nickels role in plant nutrition management in agricultural crops in general. This will have great impact on the productivity and profitability of many woody and legume crops worldwide. The “mouse-ear” and “little-leaf” disorders (i.e., nickel deficiencies) were cured for pecan, river birch, hydrangea, and other woody perennial crops. This solved replant disorders in pecan orchards, problems with unmarketable plants in woody perennial ornamental nurseries, and promises to be a contributing factor in replant problems and recalcitrant disorders in a variety of tree crops. A commercial nickel fertilizer product was developed and registered for use in U.S. agriculture, thus providing American farmers, nurserymen, and gardeners with a legal and safe fertilizer product. Research efforts led to the official recognition by fertilizers regulators of nickel as an essential plant nutrient element, thus opening enabling usage of nickel as a fertilizer product in the U.S. A method was developed for control of mistletoe pests in deciduous trees, thus identifying a means by which difficult to control weed parasites can be eliminated from orchards and yard trees. A carbohydrate based “conceptual tool” was provided to farmers that enabled management of environmental stresses to reduce alternate bearing related crop losses, thus improving orchard yields and profitability. The importance of managing pecan aphids was identified as a key factor tied to reducing alternate bearing related crop losses; thus the pest status of aphids was increased to that of a primary pest, and management strategies were developed to enable improved yields and profitability. Mechanical pruning methods were refined and guiding principles established that enabled farmers better control over orchard crowding, light environment stresses, and alternate bearing, thus contributing to the adoption of mechanical pruning in a large percentage of the U.S. pecan industry, and subsequent positive impacts on yields and profitability. Orchard yields were shown to often be limited by poor cross-pollination; guidelines were provided that ensured improved yields, thus impacting crop quality and profitability. A water management related method was developed to reduce the magnitude of crop losses due to water-stage-fruit-split, thus providing growers a means of reducing crop losses. Collaborative research produced the first genetic linkage maps of pecan, thus providing linkage markers useful in the selection of genetically superior types in efforts to produce superior cultivars for farmers. Pecan scab occurring on the nuts was not related to the severity of scab on leaf tissue; thus disease control was modified to vigorously concentrate fungicide applications on the developing fruit, not the foliage. Phytophthora cactorum, the causal agent of Phytophthora shuck and kernel rot was moved from orchard soils to the pecan fruit by emerging pecan weevil; thus a system was developed and presented to growers on how to identify and control the disease. Shuck Decline is a complex of pathogens, stress factors and susceptible cultivars and is a production limiting disorder; thus growers were advised on measures to reduce the affect of the complex disorder. The accomplishments are tied key objectives of the Pecan Production and Protection Project Plan and to ARS National Program NP-305 (Integrated Crop Production and Protection) and NP-303. For NP-305 it addresses Component I: Integrated Production Systems; and for NP-303 it addresses Component III: Cultural Controls. 6.What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end-user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? Technology has been transferred regarding: a) nickel nutrition management (scientists, extension, farmers); b) commercial nickel fertilizer product (industry, farmers); c) control of mistletoe (scientists, et al.); d) mechanical pruning guidelines and strategies (scientists, extension, and farmers); e) aphid control (scientists, extension, and farmers); f) mouse-ear and little-leaf control (scientists, extension, nurserymen, and farmers); g) alternate bearing control (scientists, extension, farmers); h) partial control of water-stage-fruit-drop (scientists, extension, farmers); i) scab control strategy (scientists, extension, farmers); j) control of black nut disease (scientists, extension, farmers); and k) control of shuck decline (scientists, extension, farmers). Technology is likely to be available to farmers in 2009 for improving fruit retention; for thinning excessive crop loads; for mechanical pruning orchards in low light environments (e.g., southeastern U.S.); for prevention of pre-harvest sprouting; for improved scab control; and for improved control of Phytophthora shuck and kernel rot and shuck decline. 7.List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: List your peer reviewed publications below). Wood, B.W., Stalmann, D. 2005. Australian research shows hedge pruning can reduce alternate bearing in pecans. Australian Nutgrower. 19(1):8-13. Wood, B.W. 2005. Fruit-drop in pecan. Pecan South. 38(4):24-26. Wood, B.W., Goff, W., Nesbitt, M. 2005. Hurricanes and the future of the southeastern pecan industry. Southeastern Pecan Growers Meetings Proceedings. 98:100-112. Wood, B.W. 2004. Nickel nutrition of pecan. Pecan Grower. 16(2):4-7. Wood, B.W., Reilly, C.C. 2004. Frances impacts pecan research. Pecan Grower. 16(2):5. Wood, B.W. 2005. Improving nitrogen management. Pecan Grower. 16(3):10-13. Wood, B.W., Kaplan, K. 2005. Impact of agriculture research. Pecan Grower. 16(4):22-26. Wood, B.W. 2005. Hedging pruning: guiding principles. Western Pecan Growers Association Proceedings. p. 11-16. Wood, B.W., Goff, W. 2004. Coping with blown over trees. Pecan Grower. 16(2):20-21. Wood, B.W. 2005. Hedge pruning in pecan: some notes on its history. Australian Nutgrower. 19(2):9-10. Thomas, S.H., Potenza, C., Jacobson, A.L., Guchs, J.M. 2004. Differentiation of Meloidogyne partiyla from other root-knot nematode species in pecan using mu-DNA: the Meloidogyne chitwoodi cytochrome oxidase subunit II partial gene sequence. GenBank 672411, 672412, 672413. Sammis, T.W., Andales, A., Simmons, L. 2004. Adjustment of closed canopy crop coefficients of pecans for open canopy orchards. 38th Western Irrigation Pecan Conference Proceedings. March 7-9, 2004, Las Cruces, New Mexico. p. 117-119. Lindemann, W.C., Tahboub, M.B., Herrera, E.A. 2004. Decomposition of pecan wood chips. 38th Western Irrigated Pecan Conference Proceedings. March 7-9, Las Cruces, New Mexico. p. 108-116. Review Publications Beedanagari, S.R., Dove, S.K., Wood, B.W., Conner, P.J. 2005. A first linkage map of pecan cultivars based on RAPD and AFLP markers. Theoretical and Applied Genetics. 110:1127-1137. Wood, B.W., Conner, P.J., Worley, R.E. 2004. Insight into alternate bearing of pecan. Acta Horticulturae. 63:617-629. Wood, B.W., Reilly, C.C., Nyczepir, A.P. 2005. Correcting Ni deficiency in pecan and other crops [abstract]. Hortscience. 40(4):1065.