Preharvest Aflatoxin Contamination in Drought-Tolerant and Drought-Intolerant Peanut Genotypes1

Abstract

Peanuts become contaminated with aflatoxins when subjected to prolonged periods of heat and drought stress. The effect of drought tolerance on aflatoxin contamination is not known. The objectives of this research were to evaluate preharvest aflatoxin contami nation in peanut genotypes known to have drought tolerance and to determine the correlation of drought tolerance characteristics with aflatoxin contamination. Twenty genotypes with different levels of drought toler ance were grown in Yuma, AZ«(a desert environment) and under rain-protected shelters in Tifton, GA. Two drought-tolerant genotypes (PI 145681 and Tifton 8) and an intolerant genotype (PI 196754) were selected for further examination in a second experiment with two planting dates in 1997 at Tifton. Drought and heat stress conditions were imposed for the 40 d preceding harvest. The drought-intolerant genotype had greater preharvest aflatoxin contamination than Florunner (the check cultivar) in the tests conducted in 1997. Both droughttolerant genotypes had less preharvest aflatoxin con tamination than Florunner in these tests. Significant positive correlations were observed between aflatoxin contamination and leaf temperature and between afla toxin contamination and visual stress ratings. Leaf tem perature and visual stress ratings are less variable and less expensive to measure than aflatoxin contamination. Leaf temperature and visual stress ratings maybe useful in indirectly selecting for reduced aflatoxin contamina tion in breeding populations.

Resistance to pre-harvest aflatoxin contamination in ICRISAT’s groundnut mini core collection

“…Earlier studies have established that severe drought promoted growth and persistence of A. flavus population in soils, thereby resulting in high aflatoxin levels in crops (Arunyanark et al 2010). Drought tolerant genotypes have been also reported to have tolerance to aflatoxin contamination (Holbrook et al 2000b;Girdthai et al 2010). For selection of resistance sources under field conditions, Niger was selected because it is one of the hottest countries in the WCA region.…”

Impact of Drought Stress on Peanut (Arachis hypogaea L.) Productivity and Food Safety

“…Molecular markers have been used to aid in the breeding process, but the low level of polymorphism in cultivated peanut has interfered with this approach. Although peanut germplasm with reduced drought tolerance have been identified and screened in breeding populations (Holbrook et al, 2000), peanut growers currently cannot rely fully on the available drought tolerant cultivars, as they are location specific. Therefore, the use of genetic engineering technology to over-express drought tolerant genes in peanut is an attractive prospective way to improve tolerance.…”

“…Besides affecting food quality, drought stress is also known to alter nutritional quality of peanut seed proteins. Since peanut lack desirable genetic variation in drought and aflatoxin tolerance several conventional as well as molecular breeding techniques were adopted to improve drought and aflatoxin tolerance (Mehan et al, 1986;Dorner et al, 1989;Holbrook et al, 2000). Recently several advanced molecular tools have been developed to screen drought tolerance in peanut genotypes.…”

Phenotyping Peanut Genotypes for Drought Tolerance

“…Irrigation, however, is not available for most peanut growing areas. The development of drought-resistant genotypes had been viewed as a potential solution (Holbrook et al, 2000).…”