Department of Animal Biology, Laboratory of Entomology and Acarology, Sciences and Technics Faculty, Cheikh Anta DIOP University, Dakar, Senegal.
Senegalese Institute of Agricultural Research (ISRA), Dakar, Senegal.
PLoS One. 2020 Apr 24;15(4):e0232164. doi: 10.1371/journal.pone.0232164. eCollection 2020.
Maize (Zea mays L) is one of main nutrients sources for humans and animals worldwide. In Africa, storage of maize ensures food resources availability throughout the year. However, it often suffers losses exceeding 20% due to insects such as the larger grain borer, Prostephanus truncatus (Horn) (Coleoptera; Bostrichidae), major pest of stored maize in the tropical countries. This study aims to select resistant varieties to reduce maize storage losses and explain the physicochemical parameters role in grains susceptibility. In the first study, maize grains were artificially infested under no-choice method with insects. Susceptibility parameters such as weight loss, grain damage, number of emerged insects, median development time and susceptibility index varied significantly through maize varieties. Dobie susceptibility index (SI) was assessed as a major indicator of resistance. The most resistant varieties were Early-Thaï, DMR-ES and Tzee-Yellow. Conversely, Synth-9243, Obatampa and Synth-C varieties were susceptible. SWAN, Across-Pool and Tzee-White were classified as moderately resistant varieties. The insect reproductive potential was significantly different in the nine maize varieties and Early-Thaï, DMR-ES and Tzee-Yellow varieties were the least favourable host. To assess the relationship between grains physicochemical characteristics and varietal susceptibility, moisture, total phenolics, palmitic acid, proteins, amylose, density and grain hardness were evaluated according to standardized methods. Palmitic acid, SI, insects emerged and grain damage were significantly and positively correlated with each other, and negatively correlated with grains hardness, phenolics and amylose contents. Maize susceptibility index was significantly and negatively correlated to amylose, and phenolics contents and positively correlated to palmitic acid content. This study identified three resistant maize varieties to P. tuncatus and revealed that the major factors involved in this resistance were hardness, phenolic and amylose contents of grains.
玉米（Zea mays L）是全世界人类和动物的主要营养来源之一。在非洲，储存玉米可确保全年都有食物资源。然而，由于昆虫如大谷蠹（Prostephanus truncatus （Horn））（鞘翅目；象甲科）等的存在，玉米经常遭受超过 20%的损失，大谷蠹是热带国家储存玉米的主要害虫。本研究旨在选择抗虫品种，以减少玉米储存损失，并解释颗粒易感性的理化参数作用。在第一项研究中，采用非选择性方法人工感染昆虫，对玉米籽粒进行感染。敏感性参数，如失重、籽粒损伤、成虫数量、中值发育时间和敏感性指数，因玉米品种的不同而显著变化。多比（Dobie）敏感性指数（SI）被评估为抗性的主要指标。最具抗性的品种是早期泰（Early-Thaï）、DMR-ES 和 Tzee-Yellow。相反，Synth-9243、Obatampa 和 Synth-C 品种则易受感染。SWAN、Across-Pool 和 Tzee-White 被归类为中度抗性品种。在这 9 个玉米品种中，昆虫的繁殖潜力有显著差异，早期泰（Early-Thaï）、DMR-ES 和 Tzee-Yellow 品种是最不利的宿主。为了评估颗粒理化特性与品种易感性之间的关系，根据标准化方法评估了水分、总酚、棕榈酸、蛋白质、直链淀粉、密度和颗粒硬度。棕榈酸、SI、成虫出现和籽粒损伤彼此之间呈显著正相关，与籽粒硬度、酚类和直链淀粉含量呈负相关。玉米敏感性指数与直链淀粉、酚类含量呈显著负相关，与棕榈酸含量呈正相关。本研究鉴定了三种对 P. tuncatus 具有抗性的玉米品种，并揭示了与这种抗性相关的主要因素是颗粒的硬度、酚类和直链淀粉含量。
