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United States Department of Agriculture

Agricultural Research Service

Research Project: PHYSIOLOGICAL MECHANISMS THAT DETERMINE CROP RESPONSE TO IRRIGATION, DISEASE AND PRODUCTION PRACTICES
2007 Annual Report


1a.Objectives (from AD-416)
Objective 1: Identify physiological drought responses to quantify water-use efficiency and other physiological characteristics that influence peanut yield and quality (aflatoxin contamination, flavor, maturity) and how these traits may differ among resistant and susceptible cultivars. Objective 2: Characterize the physiological processes and genetic expression changes that impact a level of disease tolerance to Tomato Spotted Wilt Virus in peanuts. Objective 3: Develop new peanut cultivars for low input bio-diesel production systems in low input irrigated and non-irrigated systems.


1b.Approach (from AD-416)
The effectiveness of most production practices is evaluated at harvest by examining final yield. However, an understanding of the mechanisms that drive these final yield numbers is vital in determining the efficacy of production strategies and technologies. Most causal mechanisms are physiologically based; therefore, an examination of the physiological response to the production environment can help determine how production practices succeed or fail. Research will be conducted to investigate and improve the understanding of the physiological responses to environment, climate, and production practices that ultimately determine peanut yield and quality. Major emphasis will be directed towards examining the effects of irrigation type and amount on peanut physiological water use and evaluating water-use efficiency under varying water environments. Emphasis will also be placed on plant and kernel susceptibility to aflatoxin contamination and tomato spotted wilt virus, and their effects on water use and other plant and kernel physical characteristics. A quality natural resource base is a vital factor in the viability of rural economies to sustain agricultural productivity. Available water supply is being stretched by rapidly growing demands for water by urban populations, irrigated agriculture, industry/energy sectors, and in-stream flow requirements. The dilemma for producers and local economies is finding solutions that help reduce irrigation and natural resource consumption while at the same time maintaining and or enhancing producer net returns.


3.Progress Report
Data is currently being analyzed on appropriate physiological and genetic responses to drought obtained from tillage X irrigation study. A pilot study examining early drought responses (the period determined to be the most successful in increasing water-use efficiency) has been established collaboratively between Rowland and Dang. Data collection is ongoing.

The second year of the rainout shelter study is being conducted and data collected currently.

Year 2 of data collection and analysis of physiological and genetic responses in the field study examining TSWV resistance among insecticide treatments and peanut varieties is ongoing. Analysis of physiological and genetic responses has revealed good correlation between the two processes and the identification of several traits that may be promising for genotype screening for TSWV resistance. Protocols for PCR analysis of TSWV genetic material have been created and will be used to support concurrent ELISA testing.

Additional progress: Hiring of vacant plant breeder position was completed and the new SY, Dr. Charles Chen, started in May of 2007. Dr. Chen has initiated the following evaluations: 132 breeding lines were planted at Brownfield, Texas for selecting high yield, early maturity, and high oleic and low linolenic; 265 breeding lines and 327 lines have been planted in Headland, AL and Dawson, GA, respectively. For these lines, selections will be focused on high yield, resistant to TSWV, leaf spot and high seed quality. The biochemist, Dr. Phat Dang, established the instrumentation in his molecular lab and has begun RNA testing on plant and viral genetic material


4.Accomplishments
Acclimation response of peanut to deficit irrigation: pinpointing water application to increase drought tolerance. Water scarcity in peanut production is a problem across the U.S. but is especially acute in west Texas where depletion of the primary water source (Ogallala aquifer) is projected to occur in the next two decades. A two-year project aimed at developing irrigation schemes that maximize peanut production in the semi-arid environment of west Texas while reducing overall water consumption was completed. Several irrigation schemes utilizing deficit irrigation timed to peanut developmental stages were identified and shown to maintain yield and quality equal to full irrigation, translating into significant irrigation savings. This research has provided growers in this region alternative irrigation schemes to combat inadequate irrigation supplies and improve water-use efficiency in the crop. Internationally, the research group has been approached by the Peanut Company of Australia to test these irrigation schemes in that country. Addresses Component 2. Biological Processes that Improve Crop Productivity and Quality; Problem Statement 2A: Understanding Growth and Development, and Problem Statement 2B: Understanding Plant Interactions with Their Environment.

Effects of irrigation method and tillage regime on peanut reproductive processes. Many concerns have been voiced by growers that conservation tillage would interfere with peanut reproduction, namely the formation of flowers and pegs. However, there are great benefits to conservation tillage via lowered soil erosion and water loss. A study was completed to determine if there were any differences between a conventional tillage system and a conservation tillage system that had at least 30% cover over the surface of the ground. Very few differences were detected between the two tillage systems and it was concluded that there were no ill effects of conservation tillage on the reproduction of peanuts. This research removed one roadblock to the utilization of conservation tillage systems by peanut growers in the southeast so that they could take advantage of the soil and water conservation characteristics of this type of production. This work has resulted in a scientific publication and dozens of speaking invitations from grower groups. Addresses Component 2. Biological Processes that Improve Crop Productivity and Quality; Problem Statement 2A: Understanding Growth and Development, and Problem Statement 2B: Understanding Plant Interactions with Their Environment.


5.Significant Activities that Support Special Target Populations
none.


6.Technology Transfer

Number of non-peer reviewed presentations and proceedings15
Number of newspaper articles and other presentations for non-science audiences5

Review Publications
Niehuis, O., Judson, A., Werren, J., Hunter, W.B., Dang, P.M., Dowd, S.E., Grillenberger, B., Beukeboom, L., Gadau, J. 2007. Species diagnostic single-nucleotide polymorphism and sequence-tagged site markers for the parasitic WASP Genus Nasonia (Hymenoptera: Ptermalidae). Journal of Economic Entomology. 100:1033-1036. 2007.

Chen, C., Bowman, K.D., Choi, Y.A., Dang, P.M., Rao, M., Huang, S., Soneji, J.R., Mccollum, T.G., Gmitter, Jr, F.G. 2007. EST-SSR genetic maps for Citrus sinensis and Poncirus trifoliata. Tree Genetics and Genomes. 4:1-10. 2008.

Last Modified: 10/24/2014
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