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ARS Home » Midwest Area » Urbana, Illinois » Soybean/maize Germplasm, Pathology, and Genetics Research » Research » Publications at this Location » Publication #282530
Title: Methods and evaluation of soybean genotypes for resistance to Colletotrichum truncatum

Author
item YANG, HUI-CHING - University Of Illinois
item Hartman, Glen

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/24/2014
Publication Date: 1/1/2015
Citation: Yang, H., Hartman, G.L. 2015. Methods and evaluation of soybean genotypes for resistance to Colletotrichum truncatum. Plant Disease. 99:143-148.

Interpretive Summary: Anthracnose of soybean is a fungal disease that occurs throughout the major soybean production areas of the world. The fungal species that cause soybean anthracnose infect all parts of the soybean plant. There is little information on standardizing an inoculation technique or on evaluating soybean germplasm for resistance. There are no soybean commercial soybean cultivars advertised with resistance to this disease. The objectives of this study were to develop a standardized inoculation technique to evaluate soybeans for resistance to anthracnose and to use this technique to evaluate soybeans cultivars previously reported to be resistant to anthracnose. Among 15 cultivars tested, Mandarin, Mandarin 507, and Mandarin (Ottawa) had higher levels of resistance than most other genotypes tested. This study provided a descriptive method to inoculate soybean plants and to identify genotypes with resistance to anthracnose. This information will be useful to soybean breeders, plant pathologists, and others interested in crop improvement through host plant resistance.

Technical Abstract: Anthracnose of soybean [Glycine max (L.) Merr.] occurs throughout the soybean production areas of the world. The fungal species that cause soybean anthracnose infect all parts of the soybean plant. There is little information on standardizing an inoculation technique or on evaluating soybean germplasm for resistance. The objectives of this study were to develop a standardized inoculation technique to evaluate soybeans for resistance to anthracnose and to use this technique to re-evaluate soybeans genotypes previously reported to be resistant to anthracnose. The experiments were conducted to develop a standardized inoculation technique included evaluating inocula (conidia vs. mycelia), duration of wetness of inoculated plants, and age of inoculated plants. The comparison of mycelial and conidial inocula showed that the mycelial suspension was as effective in causing anthracnose symptoms than the conidial suspension. The optimized duration of wetness of inoculated plants with mycelia was 48 h in wetness at soybean growth stages V1 to V3. Fifteen soybean genotypes were selected and assessed for resistance to Colletotrichum truncatum. Among 15 genotypes tested, Mandarin, Mandarin 507, and Mandarin (Ottawa) had the greatest (P < 0.05) level of resistance to C. truncatum compared to the other genotypes except for Early White Eyebrow that appeared to be as resistant as Mandarin (Ottawa). This study provided a descriptive method to inoculate soybean plants and to identify genotypes with resistance to anthracnose.