A negative correlation between constitutive and inducible resistance across plant populations is expected for a variety of reasons; however, empirical evidence for such trade-offs remain ambiguous, particularly for crop plants. The current study investigated the relationship between constitutive and inducible resistance in vegetative-stage soybeans (V5-V6) against larvae of the generalist defoliator, Spodoptera frugiperda. Eighteen soybean genotypes differing in their constitutive resistance to coleopteran or lepidopteran defoliators were used over four experiments. Exogenous jasmonic acid (JA, 2 mM) was used to induce plants. Constitutive resistance of each genotype was estimated by measuring weight gains, foliar consumption, and foliar conversion efficiency in short-term feeding assays on excised leaf disks of terminal trifoliate leaves of plants not treated with JA. JA was applied to plants immediately after removing leaf material for assays of constitutive resistance, and induced resistance was estimated 48 h after application of JA using leaf disks from the remaining leaf tissue of the same trifoliate used for measuring constitutive resistance. Larval weight gains before JA treatments revealed genotypic variability in constitutive resistance. . Overall, reductions in weight gain (28.7% to 76.7%), foliar consumption (3.7% - 65%) and conversion efficiency (10.9% - 42.2%) were found in JA treatments. Significant (P < 0.05) or marginally significant (P < 0.10) negative correlations between constitutive resistance (larval weight gains on non-induced plants) and induced resistance (differences in weight gains before and after induction) were found in all four experiments, suggesting tradeoff between the two modes of resistance does exist in soybean for this herbivore. Additional evidence for tradeoffs between constitutive and inducible resitance was also found in the analysis of consumption data. Comparisons of consumption and conversion efficiencies suggest that similar antibiotic and antixenotic factors are involved in constitutive and inducible resistance to fall armyworm in soybean.

由于多种原因，预计植物种群的组成型和诱导型抗性之间存在负相关；然而，这种权衡的经验证据仍然不明确，特别是对于农作物而言。目前的研究调查了营养阶段大豆 (V5-V6) 对全能落叶昆虫Spodoptera frugiperda幼虫的组成型和诱导型抗性之间的关系. 在四个实验中使用了十八种大豆基因型，这些基因型对鞘翅目或鳞翅目落叶者的组成抗性不同。外源茉莉酸 (JA, 2 mM) 用于诱导植物。每种基因型的组成抗性是通过测量未用 JA 处理的植物的末端三叶叶的切下叶盘的短期饲养测定中的增重、叶面消耗和叶面转化效率来估计的。在去除叶子材料后立即将 JA 应用于植物以进行组成抗性测定，并在使用来自用于测量组成抗性的相同三叶的剩余叶组织的叶盘应用 JA 后 48 小时估计诱导的抗性。JA 处理前幼虫体重增加揭示了组成抗性的基因型变异性。. 全面的，在 JA 处理中发现增重（28.7% 至 76.7%）、叶面消耗（3.7% - 65%）和转化效率（10.9% - 42.2%）减少。重要的 （P < 0.05) 或略显着 ( P < 0.10) 在本构抗性（未诱导植物的幼虫体重增加）和诱导抗性（诱导前后体重增加的差异）之间呈负相关，这表明两者之间存在权衡对于这种食草动物，大豆中确实存在两种抗性模式。在对消费数据的分析中还发现了本构和诱导电阻之间权衡的其他证据。消耗和转化效率的比较表明，相似的抗生素和抗毒因子参与了大豆中秋粘虫的组成型和诱导型抗性。