Submitted to: Multicrop Aflatoxin and Fumonisin Elimination and Fungal Genomics Workshop-The Peanut Foundation
Publication Type: Abstract only
Publication Acceptance Date: 9/15/2003
Publication Date: 12/15/2003
Citation: Liao, B., Lei, Y., Wang, S., Jiang, H., Holbrook, Jr., C.C., Guo, B.Z. 2003. Reaction to aflatoxin contamination among peanut germplasm lines with resistance to bacterial wilt [abstract]. In: Proceedings of the 3rd Fungal Genomics, 4th Fumonisin, and 16th Aflatoxin Elimination Workshops, October 13-15, 2003, Savannah, Georgia. p. 60. Interpretive Summary:
Technical Abstract: Peanut is an important oilseed as well as cash crop for farmers in China. Bacterial wilt (BW) caused by Ralstonia solanacearum has been among the major constraints to peanut production in central and south China. As a soil-born bacterial disease, BW is very difficult to control, and the only feasible management approach is planting BW-resistant peanut cultivars. In most cases, BW-resistant cultivars are essential for production in the heavily-infested regions. China has a large collection of BW-resistant peanut germplasm and the incidence of BW in the fields has been reduced drastically due to the improved resistant cultivars. However, the warm and moist weather in the areas with bacterial wilt disease is also favorable for infection of Aspergillus flavus, A. parasiticus, and aflatoxin contamination. Therefore, all the BW-diseased areas are also suffering from serious aflatoxin contamination in central and south China. Genetic improvement for resistance to aflatoxin contamination based on the BW resistance is crucial to comprehensive management of both constraints, and the diversified BW-resistant germplasm has made this possible. By root cross-inoculation of R. solanacearum and A. flavus in the late growth stage of peanut, it was found that infection of R. solanacearum to immature pods could encourage pre-harvest invasion of A. flavus and increase aflatoxin contamination, but the reaction varied among BW-resistant genotypes. Several BW-resistant peanut genotypes were grown on natural BW nursery with high inoculum pressure of R. solanacearum in Hongan and disease-free field in Wuhan and tested for their natural contamination of aflatoxin. The preliminary results showed that the peanut lines with high latent infection/colonization of R. solanacearum and/or poor drought tolerance had higher aflatoxin contamination. Thirty-one lines with various BW resistance levels were investigated for their resistance to seed invasion of A. flavus and to aflatoxin production. From replicated experiments for seed resistance to invasion, it was found that Xiaohongmao had similar seed resistance to invasion as J11. It was interesting to note that Xiaohongmao has the highest oleic content and the smallest pod size among the BW-resistant genotypes. From experiments for resistance to aflatoxin production, two BW-resistant genotypes, Taishan Zhenzhu and Zhonghua 6, were found to have lowest aflatoxin contents after inoculation of A. flavus. It was also interesting to note that Taishan Zhenzhu was the BW resistance parent of Zhonghua 6. It was concluded that it would be possible to improve resistance to aflatoxin contamination based on the resistance to bacterial wilt disease.