Heritability of aflatoxin resistance traits and correlation with drought tolerance traits in peanut

Drought tolerance can be an effective tool for improving aflatoxin resistance in peanut. We evaluated 140 peanut families from 4 crosses in the F4:7 and F4:8 generations in field trials under drought and non–drought conditions to investigate the heritability (h2) of aflatoxin resistance traits, and phenotypic (rP) and genotypic (rG) correlations between aflatoxin resistance and drought tolerance traits. Data were collected for seed infection by Aspergillus flavus, aflatoxin contamination, biomass, pod yield, drought tolerance index (DTI) of biomass (BIO), DTI of pod yield (PY), harvest index (HI), SPAD chlorophyll meter reading (SCMR) and specific leaf area (SLA). High genotype x environment interactions and low to moderate h2 for seed infection and aflatoxin contamination (0.30 to 0.65) were observed, indicating difficulty with directly improving these traits. However, seed infection and aflatoxin contamination had significant negative rG with drought tolerance traits, especially with pod yield (–0.29** to–0.93**) under drought conditions, indicating that genotype selection for drought tolerance could improve aflatoxin resistance. Moreover, rG were strong between seed infection and aflatoxin contamination with HI (–0.33** to–0.89**), SLA (0.50** to 0.92**) and SCMR (–0.60** to–0.83**). The results indicate that HI, SLA, or SCMR traits under long-term drought conditions could be used as indirect indicators of aflatoxin resistance. Because measurements for SLA and SCMR are simple, realizable and rapid, SLA and SCMR may be practical and cost effective for application in large scale breeding programs.