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PRECISION AGRICULTURE INITIATIVE FOR TEXAS HIGH PLAINS FIRST BIENNIUM REPORT - 1998-1999Texas Agricultural Experiment Station
Project Title: Factors Impacting Development of a Remote Sensing Dependent Site-Specific Irrigation/Chemigation System Primary Location: Bushland, TX. Objectives:1) Determine whether multi-spectral analysis systems and other remote sensing instrumentation can differentiate between disease, insect, and drought induced stress, 2) evaluate the usefulness of remote sensing instrumentation for optimizing irrigation scheduling in pathogen infested soils, and 3) evaluate how root disease and insect infestations affect crop water use efficiency and the accuracy of PET and IRT - based irrigation scheduling models. A. Reporting Period: September 1, 1997 - August 31, 1999
Objective 1: Quantify the spatial and temporal variability of factors that can be addressed by precision agriculture practices.
Figure 1. Representative SSCP gels of PCR products from beet soilborne mosaic virus RNA 3, product 4 (1A) and product 1 (1B). Numbered lanes correspond to the following samples: lane 1, EA-1; lane 2, PL-1; lane 3, RC-1; lane 4, RC-2; lane 5, MN9807-06; lane 6, MN9807-07; lane 7, MnX, lane 8, WY96-3B; lane 9, CO96-44, lane 10, DNA standards. Banding patterns in A&B suggest different isolate groupings. In the fall of 1998, we became interested in the genomic variability of soilborne viruses, their spatial variability in the field, and how their population structures changed over time. Beet necrotic yellow vein virus (BNYVV) and beet soilborne mosaic virus (BSBMV) are two viral pathogens of sugar beet that are widespread throughout most of the major sugar beet growing regions of the United States. Like many soilborne pathogens, their distribution in fields is often highly variable. Sugar beet cultivars with high levels of genetic resistance to BNYVV have been developed and these could be planted into infested areas of the field with precision planters while non-resistant higher yielding cultivars could be planted into the rest of the field. Recently we determined that cultivars with resistance to BNYVV are highly susceptible to BSBMV. Recombination of these viruses could result in a new virus capable of overcoming host resistance. Using single strand conformation polymorphism (SSCP) analysis we are able to identify genomic variability in isolates of these viruses (Fig. 1). In the fall of 1999, we grid-soil sampled sugar beet fields, in several regions of the United States, infested with these viruses. These samples were geo-referenced and aerial photos were taken of each sampled field (Fig. 2). Viruses in each soil sample are baited out and evaluated by SSCP for genomic variability, and recombination. Samples will be taken from the same spots over the next two years to evaluate how population structures change at both the field and genomic levels. Although this research was not originally included in the plant pathology PA project list of objectives, it fits very well under this first objective of the PA program.
Figure 2. Precision agriculture technologies can be used to study genetic shifts in populations of soilborne viruses. 2A, Global positioning systems can be used to geo-reference samples from a field so the same spots can be located for future sampling. 2B, Data from grid sampling can be mapped using geographic information system software and used to evaluate changes and interactions among viral populations over time.
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