Effects of cultivar, storage period, and seed-borne fungi on aflatoxin content of cotton seeds

Abstract

ABSTRACT Non-sterilized seeds from three commercial cultivars of cotton (Gossypium barbadense L.) were examined for qualitative and quantitative estimates of seed-borne fungi. The observed fungi were Aspergillus sp.1, Aspergillus sp.2, Penicillium sp., A. flavus, Alternaria sp., A. niger, Fusarium sp., Rhizopus sp. and A. ochrecous. According to the quantitative estimates, A. niger (36.02%), A. flavus (19.29%) and Penicillium sp. (16.74%) were the most predominant fungi isolated from the seeds. Other fungi occurred at frequencies ranging from 0.21% to 10.44%. Analysis of variance showed that each aflatoxin type (A) and cotton cultivar (V) was a significant source of variation in the seed aflatoxin content , while storage period (P) was a nonsignificant source of variation. The first-order interactions A×V and A×P were always nonsignificant sources of variation. In general, aflatoxin B1 content was greater than that of B2. Two regression models, derived from stepwise multiple regression analysis, were constructed to describe the effects of the isolated fungi (independent variables or predictors) on aflatoxin content (dependent variables). The first one-variable model (R2 = 34.8%) was used to predict B1 content, while the second five-variable model (R2 = 98.2%) was used to predict B2 content. It is worth noting that species of the genus Aspergillus alone accounted for 53.6% of the total variation in B2 content. In conclusion, cottonseed is susceptible to infection with toxigenic fungi that can be harmful during storage. The study demonstrated the deleterious impacts of A. flavus and aflatoxins on the assessed seed quality measures, highlighting the need to monitor toxigenic fungi and their aflatoxins. The findings of this study might aid in the development of techniques for reducing aflatoxins in oily seeds.