Updated SCN-resistant Soybean Variety List Has More with Peking Resistance than Ever

By Greg Tylka

Iowa State University personnel contact more than 40 seed companies annually to collect details about soybean varieties that are resistant to the soybean cyst nematode (SCN). The information is compiled into an extension publication shared with farmers and those who advise them. The work is financially supported by the Iowa Soybean Association. The updated list for 2023 is available online here.

The publication includes information on varieties in maturity groups (MG) 0, 1, 2, and 3 that are available for use in Iowa. The varieties likely also are available in other states. In addition to indicating the genetic source of SCN resistance, the publication contains information on relative maturity, iron deficiency chlorosis tolerance, and herbicide resistant traits of the varieties.

SCN-resistant soybean varieties available for the 2024 season - by the numbers

• 866 varieties and five blends are in the list, 48 more than in 2022 – see figure below.
• All varieties possess SCN resistance from PI 88788 or Peking.
• 779 varieties (89%) have PI 88788 SCN resistance and 87 (10%) have Peking resistance.
• Five are blends or mixtures of soybeans with PI 88788 and Peking resistance.
• Four varieties with Peking resistance are in MG 0, 36 in MG 1, 39 in MG 2, and eight in MG 3.
• There are 40 more varieties with Peking SCN resistance than in the 2022 list - the most ever.
• 23 of 33 seed brands in the publication have at least one variety with Peking SCN resistance.
• No variety with Peking SCN resistance has a relative maturity later than 3.4.
• Most varieties have herbicide resistant traits, but 63 varieties have none.

Figure: Number of SCN-resistant soybean varieties in maturity groups 0, 1, 2, and 3 for Iowa from 1991 to 2023. In the graph, “Other sources” for 2023 include 87 varieties with Peking SCN resistance and five blends of Peking and PI 88788 SCN resistance.