关键词: 糜子, 根系性状, 抗根倒伏, 主成分分析, 品种筛选

Abstract:

【Objective】This study aimed to explore the relationship between root traits, mechanical properties and root lodging resistance of different broomcorn millet varieties, identify the key indicators for evaluating root lodging-resistant varieties, screen such varieties, and provide theoretical support and material basis for broomcorn millet breeding against root lodging. 【Method】A field experiment was conducted with 75 broomcorn millet varieties as materials at the Maozao Test Base in Shanxi Province. At the early filling stage, root mechanical, morphological and architectural indicators including root pulling force, root weight, root length, root diameter and maximum root spreading angle were measured; after the heading stage, field identification of root lodging grades was carried out. Correlation analysis and principal component analysis were used to clarify the correlation between root traits and root lodging grades, determine the key indicators for root lodging resistance evaluation, and screen high root lodging-resistant varieties by combining the ranking of comprehensive principal component scores and field identification results. 【Result】Correlation analysis between root traits and mature root lodging grades showed that root lodging grade was extremely significantly negatively correlated with root pulling force (r=-0.340**) and significantly negatively correlated with root weight (r=-0.278*). Root pulling force was significantly positively correlated with the length, surface area and volume of roots with 2.0-3.0 mm diameter (r=0.253**-0.259*) and significantly positively correlated with the maximum root spreading angle (r=0.271*). Principal component analysis revealed that the top three principal components were 2.0-3.0 mm root traits (medium-thick root factor), root weight and maximum spreading angle (root weight and overall architecture factor), and root pulling force (root mechanical property factor), with individual contribution rates of 58.417%, 18.618% and 12.314% respectively. and the cumulative variance contribution rate reached 89.349%, which are the three key factors for broomcorn millet resistance to root lodging. Combining the ranking of comprehensive principal component scores and field identification results, 7 high root lodging-resistant varieties such as Ningmi 15 and Longmi 15 were screened out. 【Conclusion】The root traits of different broomcorn millet varieties exhibit rich genetic diversity. The top three principal components of root characteristics related to root lodging in broomcorn millet are: 1) root traits of 2.0-3.0 mm in diameter (medium-thick root factor); 2) root dry matter weight and maximum spreading angle (root weight and overall architecture factor); 3) root pulling force (root mechanical property factor). These are the main identification indicators for root lodging resistance in broomcorn millet. Among them, root pulling force can be used as a direct screening indicator for lodging resistance, and root traits of 2.0-3.0 mm in diameter should be focused on in root lodging-resistant breeding. Seven varieties with high root lodging resistance, including Ningmi 15 and Longmi 15, were screened out, which can be applied in variety improvement and research.

Key words: broomcorn millet, root traits, root lodging resistance, principal component analysis, variety screening