Evaluating the Cash Cover Crop Pennycress for Resistance to Soybean Cyst Nematode.

Soybean cyst nematode (SCN, Heterodera glycines) is the most prevalent pest affecting soybean yield in the Midwest. Pennycress (Thlaspi arvense L.) and camelina (Camelina sativa [L.] Crantz), winter annual oilseeds, are being evaluated as cash cover crops in the corn-soybean production system to provide both economic opportunity and ecosystem benefits. In previous studies, pennycress has been found to be a host of SCN, while camelina has been shown to be a poor or non-host. Given host-susceptibility of pennycress to SCN, a greenhouse bioassay was performed to evaluate SCN resistance in pennycress. Pennycress lines under development in the University of Minnesota germplasm collection were used. The goal of this assay was to potentially identify SCN-resistant pennycress lines that can be used as winter cover crops to suppress SCN populations. A SCN-resistance survey variable, the Female Index (FI), ranged from 68 to 280 cysts/plant in the study. For SCN resistance in soybean, a FI value < 10 is considered resistant, while a FI value of 10-30 is considered moderately resistant. Results indicated that there is no single SCN resistance gene within this 119 line pennycress panel. Additional pennycress plants within the UMN induced-mutation panel will be tested for SCN resistance. If successful, the outcome of this research will minimize damage by SCN to soybean, while maximizing the productivity of the cropping system.