Soybean PI 494182: A New Source of More Durable Resistance to Nematode Populations.

Soybean cyst nematode (SCN; Heterodera glycines Ichinohe) is the most pervasive pest of soybean [Glycine max (L.) Merr.] in the United States and worldwide. In 2012, SCN reduced yields in the U.S. by an estimated $1 billion. These losses have been contained at a stable level with the use of resistant cultivars but, over time, genetically heterogeneous nematode populations will continue to evolve and adapt to deployed resistance alleles. New resistance sources are desired to develop new cultivars for more durable resistance. PI 494182 is a recent yellow-seeded introduction from Japan, and is resistant to HG Types 0 and 2.5.7. It is similar in nematode reaction to ‘Peking’, a major source of resistance in southern cultivars, but the two lines are genetically diverse from each other. In a cluster analysis, PI 494182 and Peking grouped in two different clusters. PI 494182 was crossed to four susceptible soybeans: ‘Prohio’, ‘5002T’, ‘Skylla’, and LG05-2870-3-1 (Sel.). Segregating progenies have been developed separately for each of the four bi-parental crosses, advanced with concurrent single plant progeny and/or single-row selections. Row selections have been made using SSR markers for SCN resistance in MAS. Three selections of F₁₇ Skylla x PI 494182, fourteen selections of F₈ 5002T x PI 494182, and four selections of F₈ Prohio x PI 494182 will undergo on-station yield testing in 2017. These selections have been evaluated in the greenhouse for SCN resistance using a standardized method, and were resistant to one or more HG Types. An additional 44 selections from the same crosses will be evaluated for uniformity and agronomic traits in 2017, along with 98 F_2:4 lines of LG05-2870-3-1 x PI 494182.