College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, China; Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA.
Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA.
J Invertebr Pathol. 2018 Nov;159:105-112. doi: 10.1016/j.jip.2018.10.002. Epub 2018 Oct 3.
We simulated larval feeding behavior in seed blends of non-Bt and Bt maize to determine if seed blends create more favorable conditions for heterozygous-resistant insects over their Bt-susceptible counterparts. Survival, growth, development, and progeny production of four genotypes of the fall armyworm, Spodoptera frugiperda, Bt-susceptible (aabb), Cry1A.105 heterozygous resistant (Aabb), Cry2Ab2 heterozygous resistant (aaBb), and Cry1A.105/Cry2Ab2 heterozygous resistant (AaBb), were evaluated in eight feeding sequences (Seq 1-8) of non-Bt and MON89034 Bt maize leaf tissue expressing the Cry1A.105 and Cry2Ab2 proteins. We report variation in the performance of the four genotypes across the feeding sequences and biological parameters measured. Three heterozygous genotypes generally outperformed the susceptible genotype in larval survival, pupation rate, pupal weight, and progeny production. The performance was greater for Aabb over aaBb, AaBb over Aabb or aaBb, in two of the feeding sequences. The findings of this study could have important implications in assessing the risk of seed blends as refuge plantings for Bt crop resistance management where resistance in the target pest is not functionally recessive.
我们模拟了非 Bt 和 Bt 玉米种子混合物中的幼虫取食行为，以确定种子混合物是否为杂合抗性昆虫创造了比其 Bt 敏感对应物更有利的条件。在 8 个非 Bt 和 MON89034 Bt 玉米叶片组织的喂食序列（Seq 1-8）中，评估了 4 种秋粘虫 Spodoptera frugiperda 基因型的生存、生长、发育和后代产量，这些基因型分别为 Cry1A.105 杂合抗性（Aabb）、Cry2Ab2 杂合抗性（aaBb）、Cry1A.105/Cry2Ab2 杂合抗性（AaBb）。我们报告了四个基因型在喂食序列和测量的生物学参数上的表现变化。三个杂合基因型在幼虫存活率、化蛹率、蛹重和后代产量方面通常优于敏感基因型。在两个喂食序列中，Aabb 的表现优于 aaBb，AaBb 的表现优于 Aabb 或 aaBb。这项研究的结果可能对评估种子混合物作为 Bt 作物抗性管理中的避难所种植具有重要意义，因为目标害虫的抗性不是功能隐性的。
