ARS | Publication request: Association between physiological traits for drought tolerance and aflatoxin contamination in peanut genotypes under terminal drought

Submitted to: Plant Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 15, 2010
Publication Date: February 15, 2010
Citation: Girdthai, T., Jogloy, S., Vorasoot, N., Akkasaeng, C., Wongkaew, S., Holbrook Jr, C.C., Patanothai, A. 2010. Association between physiological traits for drought tolerance and aflatoxin contamination in peanut genotypes under terminal drought. Plant Breeding. 129:693-699.

Interpretive Summary: Aspergillus fungi can colonize seed of several agricultural crops including peanut, and this can result in the contamination of the edible yield from these crops with the toxic chemical, aflatoxin. Breeding efforts are ongoing to attempt to develop peanut varieties which resist aflatoxin contamination, however, aflatoxin contamination is difficult and expensive to measure. Drought resistance traits are promising as indirect selection tools for improving resistance to preharvest aflatoxin contamination (PAC). The objectives of this study were to determine the effect of terminal drought on PAC and to investigate the associations between surrogate traits for drought tolerance and PAC. Traits related to drought resistance were associated well with those related to PAC under drought conditions. Specific leaf area, relative water content, chlorophyll density and drought stress ratings are the best traits for use as indirect selection tools for lower PAC. Breeding for drought tolerance using these traits as selection criteria may help to accelerate progress in developing resistance to PAC.

Technical Abstract: Terminal drought induces preharvest aflatoxin contamination (PAC) in peanut. Drought resistance traits are promising as indirect selection tools for improving resistance to PAC. The objectives of this study were to determine the effect of terminal drought on PAC and to investigate the associations between surrogate traits for drought tolerance and PAC. Field tests under rainout shelters were conducted in the dry season 2004/2005 and 2005/2006. Eleven peanut genotypes were evaluated under irrigated and terminal drought conditions. Data were recorded for physiological traits, total biomass, pod yield, Aspergillus flavus colonization and PAC. ICGV 98305, ICGV 98330, ICGV 98348, ICGV 98353, and Tifton-8 had low aflatoxin contamination in both years. Traits related to drought resistance were associated well with those related to PAC under drought conditions. Specific leaf area, relative water content, chlorophyll density and drought stress ratings are the best traits for use as indirect selection tools for lower PAC. Breeding for drought tolerance using these traits as selection criteria may help to accelerate progress in developing resistance to PAC.