Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: December 10, 2004
Publication Date: July 28, 2005
Citation: Mengistu, A., Heatherly, L.G. 2005. Incidence of Phomopsis Longicolla and Other Fungi Associated with Soybean Seed in the Early Soybean Soybean Production System Plantings in the Mid Southern USA. Phytopathology. 3:FC012. Technical Abstract: Field studies were conducted from 1995 to 1997 and in 2001 at Stoneville, MS to determine the effects of maturity group (MG), year, date of planting (DOP), and irrigation on the incidence of Phomopsis longicolla (PL), the principal causal organism for soybean seed decay. The role of Macrophomina phaseolina (MP) and Fusarium sp. (FS) in the early soybean [Glycine max (L.) Merr.] production system (ESPS) was also investigated. There was a significant effect due to year, irrigation, and MG. Maturity group averaged over years, DOP, and irrigation showed that MG IV seed had a significantly higher PL incidence than did MG V seed. There were high and significant inverse relationships between incidence of seed infected with PL and seed germination (r=-0.87, P<0.05) and between incidence of seed infected with FS and seed germination (r=-0.65, P<0.05). Irrigated treatments in dry years produced a higher level of PL than did nonirrigated treatments. The incidence of PL and other fungi varied by year. Frequent rain events at maturity resulted in significantly higher level of PL and FS. This research highlights the importance and significance of PL and also the importance of other organisms, that in combination, may inflict considerable damage on the quality of seed harvested from ESPS plantings.