Aspergillus flavus infection and aflatoxin contamination of six peanut genotypes grown under terminal drought | การติดเชื้อรา Aspergillus flavus และการปนเปื้อนสารอะฟลาทอกซินในถั่วลิสง 6 พันธุ์เมื่อกระทบแล้งในช่วงปลายของการเจริญเติบโต

End of season drought at pod filling and maturity stages can severely reduce yield and increase the risk of aflatoxin contamination. Peanut varieties with resistance to drought may reduce Aspergillus flavus infection and aflatoxin contamination. The objectives of this study were to investigate the effects of late season drought during 80 days after planting (DAP) until harvest on A. flavus infection and aflatoxin contamination and to estimate the correlation coefficients between traits related to aflatoxin contamination and the correlation coefficients between traits related to drought resistance (SPAD chlorophyll meter reading (SCMR) and specific leaf area (SLA)) and traits to aflatoxin contamination (A. flavus infection and aflatoxin contamination) of 6 peanut genotypes. The six peanut genotypes were evaluated under field conditions at the agronomy farm of the Department of Plant Science and Agricultural Resources, Khon Kaen University. The varieties were laid out in a randomized complete block design with four replications for two years in 2006/2007 and 2007/2008. A. flavus was inoculated to the crop at 30 days after planting (DAP) and soil moisture content at 1/3 field capacity was imposed to the crop at pod setting stage until harvest. The data were recorded for SCMR, SLA, A. flavus infection percentage and aflatoxin contamination. KKU 60 had the lowest A. flavus infection (14%) and aflatoxin contamination (553 ppb), whereas KKU 72-1 had the highest A. flavus infection (30%) and KKU 1 had the highest aflatoxin contamination (898 ppb). The correlation coefficients between yield and traits related to aflatoxin contamination ( A. flavus infection and aflatoxin contamination) were negative and significant, whereas the correlation coefficient between A. flavus infection and aflatoxin contamination was positive and significant. SCMR was negatively and significantly correlated with A. flavus infection and aflatoxin contamination, whereas SLA was positively and significantly associated with A. flavus infection and aflatoxin contamination. The information is useful for screening of peanut genotypes for drought resistance and reduced aflatoxin contamianation.Keywords: Arachis hypogaea L., drought tolerance, aflatoxin