Combining ability and genetic diversity under low-temperature conditions at germination stage of maize (Zea mays L.)

Low temperatures are important for the production of spring maize in northern China. While the low-temperature tolerance of maize seeds can be improved by coating them, this can result in environmental pollution, high costs, and instability. Therefore, identifying new varieties of maize is the most effective method of improving the ability of maize crops to withstand low temperatures. In this experiment, four low-temperature tolerant maize inbred lines (DNF266, Zhong 451, B73, Dan 340) and four low-temperature sensitive maize inbred lines (Luyuan 92, Ji 853, Huangzaosi, Si 144) were selected from the northern spring maize area. The griffing double-row hybridization design method was used to prepare 28 hybrid combinations. After analysing the general combining ability and the special combining ability of each combination, we found that the indoor low-temperature index and low-temperature seedings were extremely similar for all combinations. The hybridization and parental inbred lines were subjected to low-temperature treatments under both laboratory conditions and in the field. Several low-temperature indexes were assessed to identify what results could be produced from combining them. Under both treatments, the inbred line DNF266 had a higher general combining ability and the Zhong 451 × Dan 340 hybrid combination had a higher special combining ability. These results provide technical support for breeding new low-temperature varieties of maize.