Faculdade de Ciências Agrárias e Veterinárias, Campus de Jaboticabal, Departamento de Ciências da Produção Agrícola, Universidade Estadual Paulista, Jaboticabal, SP, Brazil.
Faculdade de Ciências Agrárias, Universidade Federal da Grande Dourados, Dourados, MS, Brazil.
J Econ Entomol. 2021 Feb 9;114(1):377-386. doi: 10.1093/jee/toaa292.
The rootworm Diabrotica speciosa (Germar) is native to South America and causes severe economic losses to several crops due to root feeding and disease spread. In maize (Zea mays L.), losses in production come from larval rootworm attack on plant roots resulting in plant health problems, including stalk lodging. More options for controlling this pest are needed to create well balanced, integrated pest management programs for farmers in this region. Natural sources of tolerance in maize genotypes are important for maize breeding programs, and this study investigated the expression of tolerance in several Brazilian maize landraces to D. speciosa. Plant vigor and compounds associated with plant health, including chlorophylls, carotenoids, glycine betaine, and proline were assessed for each landrace. Five landraces and one maize cultivar were selected based on their levels of antibiosis-resistance to D. speciosa that were determined in a prior screening. The percent reduction in plant growth was used as the measure of tolerance. The landrace Azteca was classified as tolerant to D. speciosa larval feeding, displaying less reduction in plant matter despite having lower plant vigor. This landrace also had higher amounts of chlorophyl and carotenoid pigments, suggesting a positive correlation between tolerance to D. speciosa and higher contents of these photosynthetic pigments. The compatible osmolytes glycine betaine and proline do not seem to be associated with tolerance in maize landraces to D. speciosa larvae. Landrace Azteca seems promising for plant breeding, and repeated field studies are needed to confirm its suitability in maize integrated pest management.
美洲玉米根萤叶甲（Diabrotica speciosa (Germar)）原产于南美洲，由于其取食作物根部并传播疾病，对包括玉米在内的多种作物造成严重的经济损失。在玉米（Zea mays L.）中，幼虫对植株根部的取食会导致植株健康问题，包括茎秆倒伏，从而造成产量损失。为了为本地区的农民制定均衡的综合虫害管理方案，需要更多控制这种害虫的选择。玉米基因型中对根萤叶甲的天然耐性来源对于玉米育种计划非常重要，本研究调查了几种巴西玉米地方品种对美洲玉米根萤叶甲的耐性表达。评估了每个地方品种的植株活力和与植株健康相关的化合物，包括叶绿素、类胡萝卜素、甘氨酸甜菜碱和脯氨酸。根据先前筛选中确定的对 D. speciosa 的抗生性水平，选择了五个地方品种和一个玉米品种。植物生长的减少百分比作为耐性的衡量标准。地方品种 Azteca 被归类为对 D. speciosa 幼虫取食具有耐性，尽管植株活力较低，但植物物质的减少幅度较小。该地方品种还具有更高含量的叶绿素和类胡萝卜素色素，这表明对 D. speciosa 的耐性与这些光合色素的更高含量之间存在正相关。相容的渗透调节剂甘氨酸甜菜碱和脯氨酸似乎与玉米地方品种对 D. speciosa 幼虫的耐性无关。地方品种 Azteca 似乎在植物育种方面很有前途，需要进行重复的田间研究来确认其在玉米综合虫害管理中的适用性。
