Location: Crop Genetics and Breeding ResearchTitle: Heritability of, and genetoypic correlations between, aflatoxin traits and physiological traits for drought tolerance under end of season drought of peanut (Arachis hypogaea L.) Author
Submitted to: Field Crops Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/15/2011
Publication Date: 12/15/2011
Citation: Girdthai, T., Jogloy, S., Vorasoot, N., Akkasaeng, C., Wongkaew, S., Holbrook Jr, C.C., Patanothai, A. 2011. Heritability of, and genetoypic correlations between, aflatoxin traits and physiological traits for drought tolerance under end of season drought of peanut (Arachis hypogaea L.). Field Crops Research. 118:169-176. 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. The objective of this study were to evaluate the association between drought resistant traits and aflatoxin traits in peanut. Field experiments were conducted for two years. Strong associations were found between drought resistant traits and fungal colonization and aflatoxin contamination. These results indicated that physiological-based selections approaches might be used to accelerate efforts in breeding peanut for reduced aflatoxin contamination.
Technical Abstract: More rapid progress in breeding peanut for reduced aflatoxin contamination should be achieved with a better understanding of the inheritance of aflatoxin traits and physiological traits that are associated with reduced contamination. The objectives of this study were to estimate the heritability of aflatoxin traits and genotypic (rg) and phenotypic (rp) correlations between drought resistance traits and aflatoxin traits in peanut. One hundred-forty peanut lines in the F4:6 and F4:7 generations were generated from four crosses, and tested under well-watered and terminal drought conditions. Field experiments were conducted under the dry seasons 2006/2007 and 2007/2008. Data were recorded for biomass (BIO), pod yield (PY), drought tolerance traits [harvest index (HI), drought tolerance index (DTI) of BIO and PY, specific leaf area (SLA), and SPAD chlorophyll meter reading (SCMR)], and aflatoxin traits [seed infection and aflatoxin contamination]. Heritabilities of A. flavus infection and aflatoxin contamination in this study were low to moderate. The heritabilities for seed infection and aflatoxin contamination ranged from 0.48 to 0.58 and 0.24 to 0.68, respectively. Significant correlations between aflatoxin traits and DTI (PY), DTI (BIO), HI, biomass and pod yield under terminal drought conditions were found (rp = -0.25** to 0.32**, rg = -0.57** to 0.53**). Strong correlations between SLA and SCMR with A. flavus infection and aflatoxin contamination were also found. Positive correlations between SLA at 80, 90, and 100 DAP and aflatoxin traits were significant (rp = 0.13** to 0.46**, rg = 0.26** to 0.81**). SCMR was negatively correlated with aflatoxin traits (rp = -0.10** to -0.40**, rg = -0.11** to -0.66**). These results indicated that physiological-based selection approaches using SLA and SCMR might be effective for improving aflatoxin resistance in peanut.