Resistance to soybean aphid biotype 4 in plant introductions of Glycine soja

Authors: CONZEMIUS, SOPHIA - South Dakota State University; Hesler, Louis; VARENHORST, ADAM - South Dakota State University; TILMON, KELLEY - The Ohio State University

Submitted to: Euphytica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/10/2019
Publication Date: 4/23/2019
Citation: Conzemius, S., Hesler, L.S., Varenhorst, A., Tilmon, K. 2019. Resistance to soybean aphid biotype 4 in plant introductions of Glycine soja. Euphytica. 215:98. https://doi.org/10.1007/s10681-019-2421-6.
DOI: https://doi.org/10.1007/s10681-019-2421-6

Interpretive Summary: The soybean aphid is a major pest of soybean in the Midwestern U.S. and southern Canada. Host plant resistance offers an alternative to insecticides for managing this pest, but challenging strains of soybean aphid, known as virulent biotypes, have the ability to overcome particular plant resistance genes. Biotype 4 is the most challenging, as it overcomes two resistance genes. To find sources of resistance to soybean aphid biotype 4, we turned to soybean’s wild progenitor, known informally as soja. Twenty soja lines previously identified with resistance to non-virulent biotypes were challenged using free-choice tests against three different colonies of biotype 4 collected from Lomira, Wisconsin in 2013 and from Volga, South Dakota in 2015 and 2016. Lines that showed resistance in the free-choice tests were followed-up a with a more stringent no-choice test against biotype 4 to confirm resistance. Free-choice tests identified a few soja lines with resistance to each of the different colonies. The follow-up with no-choice tests showed that soja lines PI 65549 and PI 101404A were resistant to each of the three colonies. These three lines may be used as sources for breeding resistance to biotype 4 into modern soybean cultivars, thus ensuring a strong, durable tactic for managing soybean aphid.

Technical Abstract: Soybean aphid (Aphis glycines Matsumura) is a pest of soybean [Glycine max (L.) Merr] in the Midwestern U.S. and southern Canada. Host plant resistance provides an alternative to insecticides for soybean aphid management approach. Soybean with Rag1+Rag2 aphid resistance is available commercially but does not protect against soybean aphid biotype 4 colonization. To find sources of resistance to soybean aphid biotype 4, we turned to soybean’s progenitor Glycine soja (Sieb. and Zucc.). Twenty soja plant introductions (PIs) with previously identified resistance to avirulent soybean aphid biotype 1 were assessed in free-choice tests against biotype 4, followed by a no-choice test for promising PIs. Experiments were repeated using three soybean biotype 4 colonies, collected from separate site-years (Lomira, WI 2013; Volga, SD 2015, 2016). Free-choice tests identified six, three, and eight soja PIs with putative resistance to Lomira13, Volga15, and Volga16 aphid colonies, respectively. No-choice tests identified six, two, and six soja PIs that continued to suppress Lomira13, Volga15, and Volga16 aphids, respectively. PI 65549 and PI 101404A were resistant to each of the three colonies of soybean aphid biotype 4 and may contribute to durable resistance against soybean aphid.