Tuesday, November 14, 2006 - 2:00 PM
159-8
Remote Sensing in Screening for Abiotic Stress Tolerance in Peanut.
Drought stress and aflatoxin contamination continue to challenge peanut (Arachis hypogaea L.) producers across the U.S. As a result, researchers have continued to investigate new varieties with enhanced resistance to drought and aflatoxin contamination. Current methods of in-season crop evaluations are qualitative and laboratory screening for aflatoxin contamination can be cost-prohibitive. However, ground-based remote sensing may be used to quantify crop response to induced drought stress and aflatoxin inoculation. The objectives of our study were twofold: 1) to evaluate canopy reflectance as a means to quantify crop response to induced drought and 2) evaluate the utility of remotely sensed estimates of drought tolerance as an indirect indicator of aflatoxin resistance. In May 2004 and 2005 several small plots (2 m x 2 m) were established at the Gibbs Farm research facilities in Tifton, GA. Treatments consisted five peanut genotypes encompassing a range of drought tolerance and yield characteristics arranged in a completely randomized block design. Drought conditions were simulated beginning 90 days after planting and maintained through harvest. Once drought conditions were established, a handheld radiometer was used to acquire twice weekly reflectance measurements in the visible and near infrared regions of the spectrum. Coincident with remotely sensed data collection standard visual ratings and soil water content (0-15cm) were acquired. Seasonal measurements included aflatoxin and yield measurements. Data are promising and indicate that remote sensing may be used to facilitate the selection of drought and aflatoxin resistant varieties of peanut. Remotely sensed vegetative indices were significantly different for drought tolerant and intolerant varieties of peanut throughout the growing season in both years. Moreover, vegetative indices were also highly correlated with yield (r = -0.50 - -0.75, alpha = 0.05) and aflatoxin contamination (r = 0.45 – 0.75, alpha = 0.05).
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