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ARS Home » Southeast Area » Stoneville, Mississippi » Crop Genetics Research » Research » Publications at this Location » Publication #412640
Research Project: Breeding Stress Tolerant Soybeans, Regeneration and Evaluation of USDA Germplasm Collection,and Management of Uniform Soybean Trials

Location: Crop Genetics Research

Title: Diaporthe longicolla as a seed adn stem pathogen of soybean (Glycine max L.)

Author
item SURESHBABU, BIJULA - North Dakota State University
item MOHAN, KARTHIKA - North Dakota State University
item RAFI, NITHA - North Dakota State University
item Gillen, Anne
item Smith, James - Rusty
item MATHEW, FEBINA - North Dakota State University

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 2/12/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Diaporthe seed decay of soybean (Glycine max), caused by Diaporthe longicolla, negatively affects seed quality. However, there is limited information on whether seed decay is related to pod and stem blight caused by D. longicolla. This study aims to assess the relationship between stem and seed infection caused by D. longicolla by examining a total of 39 accessions. To induce stem infection, a mycelial plug from a seven-day-old culture of a North Dakota isolate was inoculated at the second trifoliate growth stage of the plants. The inoculated plants were then placed in humidity chambers maintained at 25±3ºC with 90% humidity. Seven days post-inoculation (dpi), the plants were assessed on a scale of 0 (dead) to 1 (no stem symptoms). For the seed experiment, the seeds of each genotype were surface-sterilized and immersed in a mycelial solution for 4-h. After incubation, the seeds were plated on 2% water agar and incubated for 7-d at 23±2ºC under laboratory conditions. At 7 dpi, the seeds were rated on a scale of 0 (healthy) to 3 (diseased seeds and rotting cotyledons). The stem and seed experiments were conducted twice in a completely randomized design with eight replications per experiment. A significant effect of genotype on disease severity was observed for stem infection (p<0.0004) and seed decay (p<0.0003). Eight genotypes were significantly less susceptible to stem infection compared to the susceptible check 'Hawkeye' (PI548577), but none of the genotypes were significantly less susceptible to seed infection. When the correlation between stem infection and seed decay in all genotypes was analyzed, no significant correlation was observed (p>0.05). These findings suggest that pod and stem blight may not be a reliable indication of seed decay. Further investigations are necessary to better understand the observations made in this study, including a larger number of cultivars and segregating germplasm.