Progress In The Fight Against Soybean Seed Decay

Much has been said and written about the seed decay problem (often called Phomopsis seed decay or PSD) that plagues soybeans in the Midsouth. I want to get you up to date on advances that have been made and current projects that should lead to further advances to aid in the management and control of this costly problem for Mississippi soybean farming.


Breeding for resistance to PSD is believed to be the most effective strategy for controlling PSD. In the latest issue of Crop Science, Drs. Shuxian Li and James (Rusty) Smith with USDA-ARS at Stoneville and Dr. Randy Nelson with USDA-ARS at Urbana, IL report positive news in this area.

They have identified two Plant Introductions (PI’s 424324B and 458130, obtained from the USDA Soybean Germplasm Collection at Urbana IL) that are resistant to Phomopsis longicolla, the organism that is the primary cause of PSD in soybeans. These resistant accessions can be used to develop varieties that are resistant to PSD. According to Dr. Li, the senior author of the publication, breeding populations with either of these two PI’s as a parent are being developed.

In an earlier paper published in Journal of Heredity, scientists at the University of Arkansas reported the finding of a new gene for PSD resistance in PI 360841. This gene, along with different genes in other lines that also confer resistance to PSD, offers opportunities for breeders to develop lines with strong PSD resistance.

Currently, there are four MSPB-funded projects that address PSD. Scientists affiliated with these projects are studying the impact of fertility and fungicide application strategies on PSD prevention, the development of PSD-resistant soybeans from new sources of resistance, and identifying soybean varieties, if any, that may have PSD resistance. The Arkansas, Tennessee, and United Soybean Boards are also funding projects where scientists are screening soybean varieties, breeding lines, and germplasm for PSD resistance.

As I stated in an earlier blog, breeding and variety development will provide advances that arguably will have the greatest impact on sustainable soybean production in the US and Midsouth. The potential genetic resources for host-plant resistance to PSD coming from the above studies and projects support this premise.

In the near future, I hope to bring you further good news that varieties with PSD resistance are available for Mississippi soybean farming.

Another important point: The funding provided by the various state soybean boards and the United Soybean Board to address the seed decay problem in soybeans is an invaluable and indispensable resource.


larryheatherly@bellsouth.net

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