Ni Xinzhi, Xu Wenwei, Blanco Michael H, Williams W Paul
USDA-ARS, Crop Genetics and Breeding Research Unit, University of Georgia-Tifton, Tifton, GA, 31793.
Insect Sci. 2014 Oct;21(5):541-55. doi: 10.1111/1744-7917.12093. Epub 2014 Feb 12.
After examining ear-colonizing pest resistance, 20 maize lines from the USDA-ARS Germplasm Enhancement of Maize (GEM) Program were evaluated for whorl-feeding fall armyworm (FAW) (Spodoptera frugiperda) resistance using 4 maize inbred lines as the resistant and susceptible controls. Both FAW injury ratings at 7- and 14-d after infestation, and predator abundance and diversity at whorl stage (V6-V8) were recorded in 2009 and 2010. The survey of the diversity and abundance of predators in each experimental plot were conducted 7 d after the FAW infestation. Of the 20 germplasm lines examined, 3 of them (i.e., entries 9, 15, and 19 that were derived from tropical maize germplasm lines were originated from Uruguay, Cuba, and Thailand, respectively) were identified as the best FAW-resistant germplasm lines using the leaf injury ratings and predator survey data. In addition, the abundance and diversity of the predators were greater in 2010 than in 2009, which might have caused the low level of the FAW injury ratings on all lines examined in 2010. The 2-year data showed that the FAW injury ratings were negatively correlated to the predator abundance and diversity, which is also influence by genotype × environment interactions. The findings suggested that tropical germplasm is an important source of native resistance to the FAW and the corn earworm. At the same time, the maize genotype × environment interaction (e.g., predator attractiveness, and varying weather conditions) should be included in the multiple-year evaluations of insect and disease resistance of maize germplasm lines under field conditions.
在检测了耳部定殖害虫抗性后，利用4个玉米自交系作为抗性和感病对照，对来自美国农业部农业研究局玉米种质资源增强计划（GEM）的20个玉米品系进行了心叶期取食的草地贪夜蛾抗性评估。在2009年和2010年记录了侵染后7天和14天的草地贪夜蛾伤害评级，以及心叶期（V6 - V8）的捕食者丰度和多样性。在草地贪夜蛾侵染7天后，对每个试验小区的捕食者多样性和丰度进行了调查。在所检测的20个种质系中（即其中3个，分别来自乌拉圭、古巴和泰国的热带玉米种质系的编号9、15和19），利用叶片伤害评级和捕食者调查数据，确定它们为最佳的草地贪夜蛾抗性种质系。此外，2010年捕食者的丰度和多样性高于2009年，这可能导致2010年所有检测品系的草地贪夜蛾伤害评级较低。两年的数据表明，草地贪夜蛾伤害评级与捕食者丰度和多样性呈负相关，这也受到基因型×环境互作的影响。研究结果表明，热带种质是草地贪夜蛾和玉米穗虫天然抗性的重要来源。同时，在田间条件下对玉米种质系的病虫害抗性进行多年评估时，应考虑玉米基因型×环境互作（如捕食者吸引力和不同的天气条件）。
