关键词: 玉米; 自交系; 耐低温; 指标; 综合评价

Abstract: 【Objective】 In recent years, extreme weather such as low temperature chilling injury occurred frequently during the sowing and emergence of maize in the northern spring maize region, resulting in slow emergence and poor uniformity of seeds, which ultimately affected the quality and yield of maize. In this study, maize germplasm from the United States, Germany, former Yugoslavia, Canada and China were selected for the identification of low temperature germination resistance, and the germplasm with strong low temperature germination resistance was selected to provide material basis and technical support for the improvement of low temperature resistant germplasm and the breeding of new varieties.【Methods】 74 maize inbred lines were taken as materials, the field survey direct method and indoor assay method were applied, through the investigation, to determine the 10 indexes such as the standard germination rate (SGR), cold immerse germination rate (CIGR), normal field emergence potential (NFEP), normal field emergence rate (NFER), low field emergence potential (LFEP), low field emergence rate (LFER), normal Field germination index (NFGI), normal field vigor index (NFVI), low field germination index (LFGI) and low field vigor index (LFVI). The ability of maize seeds to germinate under low temperature was evaluated by the method of membership function and multivariate statistical analysis. And also, the ability of maize seeds to resist low temperature germination was evaluated by using membership function and multivariate statistical analysis.【Results】 There were abundant genetic variations in the low temperature germination tolerance of maize inbred lines tested.10 appraisal index of genetic variation coefficient were between 10.10%-145.47%, and the cumulative contribution rate was 73.554%, maize inbred lines was established by stepwise regression seed germination ability at low temperature resistance comprehensive evaluation mathematics model of low temperature resistant Y_LTR=0.162+0.250X_NFGI+0.246X_LFGI.The predicted results with the method of subordinate function value (L) the evaluation results are basically identical.Finally, 74 inbred lines were divided into 5 grades based on the comprehensive evaluation value of low-temperature germination tolerance: one inbred line with very strong low-temperature germination tolerance, 12 inbred lines with rather strong low-temperature germination resistance, 45 inbred lines with moderate low-temperature germination resistance,13 inbred lines with weak low-temperature germination resistance and 3 inbred lines with extremely weak low-temperature germination resistance.【Conclusion】 The selected inbred lines Shen137, D3M and JSH2402 with very weak germination resistance at low temperature and Xinzi3113 with strong germination resistance at low temperature will be applied in the research of low-temperature QTL mapping, germplasm innovation and new variety selection.Field germination index at room temperature and field germination index at low temperature can be used as main indexes to evaluate the low temperature tolerance of inbred lines.

Key words: maize; inbred; low temperature resistance; index; comprehensive evaluation