Comprehensive Evaluation and Main Identification Indexes of Herbicide Resistance of High-Quality Foxtail Millet (Setaria italica L.)

Abstract

Foxtail millet (Setaria italica L.) is an important crop grown worldwide as a food and fodder crop owing to its potential nutritional and feed values. High-efficiency herbicide varieties is crucial to achieving efficient weeding and ensuring successful foxtail millet production. Herbicides affect several morphological and physiological indicators of foxtail millet. In this study we aimed to evaluate the damage caused by herbicides, improve their effectiveness, and select indicators that accurately reflect herbicide resistance in foxtail millet. Jingu 21, which has the largest planting area in Shanxi province and even the whole of China, is selected as the experimental material to be sown in the field in 2022. A total of 31 herbicides were applied, and 21 traits, including morphological, physiological, and yield-component traits, were measured to assess millet resistance. Principal component analysis was employed to transform these 21 conventional traits into seven independent and comprehensive indexes. These indexes were screened using regression analysis, resulting in the selection of the following indicators: the surface area of the second leaf from the top, peroxidase activity, catalase activity, malondialdehyde content, chlorophyll (a + b), grain weight per ear, and yield. Through membership function and cluster analyses, the resistance of Jingu 21 to 31 herbicides was divided into five categories: extremely weakly resistant, weakly resistant, moderately resistant, strongly resistant, and extremely strongly resistant. Jingu 21 exhibited extremely strong resistance to lactofen, butachlor, and anilofos. After an investigation into the effectiveness of herbicides, it was found that eight herbicides had good effects.