Abstract:
【Objective】 Drought is one of the important factors that restrict the growth of sugar beet, directly affecting sugar beet yield, sugar content,and sugar production so identifying the drought resistance of sugar beet during the rapid growth period of the leaf rosette,and selecting drought-resistant materials,are of great significance for the breeding of new sugar beet varieties.
【Methods】 In this study,357 domestic and foreign germplasm materials were used,and two treatments,normal irrigation and drought stress,were applied to determine seven main indicators including chlorophyll content,leaf area index,and plant height. Eight drought resistance indicators,including yield drought resistance index and comprehensive drought resistance index,were used for comprehensive evaluation of each germplasm material.Genetic diversity analysis of 72 germplasm materials was conducted using SSR molecular markers to analyze the genetic relationship between different drought-resistant germplasm materials of sugar beet.
【Results】 Under drought stress,the average values of all indicators decreased,with the decrease magnitude in the following order: yield (26.05%),sugar production (16.77%),plant height (14.85%),leaf number (8.43%),leaf area index (2.6%). There was a significant positive correlation among drought resistance indicators,and chlorophyll content,leaf area index,etc.were significantly or extremely significantly positively correlated with drought resistance indicators.
【Conclusion】 Leaf area index,plant height,leaf number,yield,and sugar production during the rapid growth period of the leaf rosette are five important indicators for determining the drought resistance of sugar beet germplasm materials under water stress. Based on the comprehensive evaluation of eight drought resistance indicators, 10 drought-resistant germplasm materials were selected. Among the 72 core germplasm materials analyzed using SSR markers,there was a close genetic relationship,and the drought-resistant germplasm materials XJT4121 and XJT1317 were sister lines.