Competitive Ability of Canola Hybrids Resistant and Susceptible to Herbicides

ABSTRACT: This work aimed to compare the competitive ability of canola hybrids susceptible (conventional) or resistant to triazine or imidazolinone group herbicides, with turnip. The experiments were conducted in greenhouse, in a completely randomized design, with four replicates. The hybrids Hyola 571CL (resistant to imidazolinone), Hyola 555TT (resistant to triazine), and Hyola 61 (conventional) were used. The treatments consisted of ratios (100:0; 75:25; 50:50; 25:75; 0:100%) of canola and turnip plants. The evaluation was performed 44 days after emergence, determining the leaf área (AF), dry matter of aerial part (MSPA), and stature (EST) of the plants. The competitiveness analysis was performed through diagrams and interpretation of the competitiveness indexes. For the canola hybrids, the competition occurred by the same mean resources. There was damage to the crop growth in competition with the turnip. The turnip was not benefited only when in competition with Hyola 571CL hybrid, for the EST variable, and with the conventional canola, for the variable AF. There was significance for the competitiveness indexes, demonstrating that turnip is more competitive then the crop. Greater AF, MSPA, and EST occurred for canola plants in the smallest proportions of turnip and, for turnip plants, in the largest proportions of canola. The ability to compete with turnip is similar among hybrids, with injury to the crop and benefit to the weed, when competing. Interspecific competition is more damaging to canola hybrids; and intraspecific competition is more damaging to turnip.摘要：本研究旨在比较对三嗪类（triazine）或咪唑啉酮类（imidazolinone）除草剂敏感（常规型）及具备抗性的油菜杂交种与芜菁的竞争能力。试验于温室环境中开展，采用完全随机设计，设置4次生物学重复。供试油菜杂交种包括Hyola 571CL（抗咪唑啉酮类除草剂）、Hyola 555TT（抗三嗪类除草剂）以及Hyola 61（常规型）。试验处理为油菜与芜菁的种植比例组合：100:0、75:25、50:50、25:75、0:100%。于出苗后44天开展性状调查，测定植株的叶面积（AF）、地上部干物质重量（MSPA）及株高（EST）。通过图表绘制与竞争指数解析开展竞争力分析。各供试油菜杂交种与芜菁的竞争模式一致，均围绕共享资源展开。与芜菁竞争时，油菜的生长会受到抑制。仅在与Hyola 571CL杂交种竞争时，芜菁的株高（EST）未获得生长增益；仅在与常规型油菜杂交种竞争时，芜菁的叶面积（AF）未获得生长增益。竞争指数分析结果存在显著差异，表明芜菁的竞争能力强于供试油菜。当芜菁种植比例最低时，油菜的叶面积、地上部干物质重量及株高均更高；而当油菜种植比例最高时，芜菁的上述性状表现更佳。各油菜杂交种与芜菁的竞争能力相近，竞争过程均会对油菜造成损伤、对作为杂草的芜菁产生生长增益。种间竞争对油菜杂交种的损害更为显著；而种内竞争则对芜菁的抑制作用更强。