Effect of Soybean Cyst Nematode on Fatty Acid Levels of Soybean Seed

Abstract

Growing soybean cyst nematode (SCN, Heterodera glycines Ichinohe) resistant varieties in fields infested with SCN can improve yield, but the impact of SCN on seed quality of lines with modified seed composition is unknown. The objective of this study was to determine if SCN resistant or susceptible rootstock influenced the composition of seed of soybean lines developed for desirable elevated levels of unsaturated fatty acids (FA). Five soybean lines with modified or normal levels of FA were Y-grafted to generate a 5-×-5 combination of plants with a SCN susceptible (SCNS) or resistant (SCNR) rootstock having a self-grafted branch, a scion (alien) grafted branch, or non-grafted branch; control plants were not grafted. In 2004 and 2005 plants were transplanted into blocks of Asgrow 3302 (SCNR) or Asgrow 3701 (SCNS) verified to be infested with SCN. Seeds were harvested at physiologic maturity (R8) in 2004 and 2005 and analyzed for five unsaturated FA. Differences in FA levels between 2004 and 2005 were significant (P < 0.05), but there were no significant (P = 0.05) block × year effects. Significant differences were observed between the FA levels of seed harvested from non-grafted control plants and self-grafted or non-grafted branches of grafted plants within lines. Seed oleic acid of the mid-oleic line S03-1379-2 was significantly greater when grafted onto an SCNR line than when grafted onto SCNS lines. The low linolenate trait appeared to be insensitive to SCN presence as seed linolenic acid of the low linolenic line IA-3017 was not different when grafted onto SCNR or SCNS lines. SCN can negatively impact the expression of seed quality of soybean if grown where SCN infestations are evident. Accepted for publication 8 September 2008. Published 3 November 2008.