| Maize due to its large production potential and the diversification of use, becomes the commodity grain of forage industry, processing industry and other fields in China, and plays an important role in economic development. In recent years, the harm caused by global warming is increasing year by year, which leads to the shortage of water resources, expansion of arid area,bringing serious harm to agricultural production especially maize production, resulting in serious losses of maize production. How to reduce the yield loss caused by drought stress is a key problem to be solved urgently in maize production. The study found that, compared to the intensive irrigation of water resources, optimization of cultivation mode, plastic film mulching and other methods, the successful breeding of new drought resistant varieties and planting could solve the effects of drought on maize production more effectively.The research on drought resistance of maize is the basic work in maize drought resistance breeding. Maize inbred lines is an intermediate material in maize drought resistance breeding,and it is also the germplasm foundation of new varieties breeding, carrying out research on drought resistance of maize inbred lines and screening the existing drought resistant strains has important practical significance for the breeding of new maize drought resistance varieties.Because maize drought resistance is a complex quantitative trait controlled by multiple genes,multiple indexes can be used to identify and evaluate the drought resistance of maize, however,the contribution rate of each index to drought resistance evaluation is different, operation difficulty is also not the same, therefore, it is necessary to effectively screen the character indexes related to drought resistance, realizing the comprehensive evaluation on drought resistance of maize inbred lines on the basis of it, and then improving the breeding efficiency of new drought resistant varieties.On the basis of summarizing the previous studies, this study takes 80 portions of elite maize inbred lines in Jilin Province as the test material, carrying out drought resistance identification in the period of germination and seedling respectively in laboratory and drought shed, and drought resistance identification in the maturity stage under the conditions of natural drought in the field, three kinds of drought resistance identification methods were used to screen the effective indexes to evaluate the drought resistance of maize in each appraisal period,then taking them as basic parameters to evaluate drought resistance performance of maize inbred lines at different stages of identification, screening out maize inbred lines with excellent and stable comprehensive drought resistance performance, providing excellent germplasmresources for the selection and breeding of new varieties of maize, and accelerating the process of maize drought resistance breeding. The main results obtained in this study are as follows:1. Through the drought resistance identification of testing maize inbred lines in three growth stages, a total of 29 character indexes were measured and analyzed. Finally, 15 effective indexes were screened to evaluate the drought resistance of testing maize inbred lines, including:(germination stage) seed germination rate, radicle length, germ length and relative germination rate under 15 % PEG drought stress;(seedling stage) fresh weight of ground parts and its drought resistance coefficient, root fresh weight and its drought resistance coefficient, dry weight on the ground and its drought resistance coefficient, root dry weight and its drought resistance coefficient, leaf proline content under drought stress;(maturity stage) plot yield and plot ear dry weight.2. Based on the selected effective indexes of drought resistance evaluation, this study comprehensively evaluated drought resistance performance of 80 portions of testing maize inbred lines at different identification stages. Finally, the following 18 portions of testing maize inbred lines were found to show stable and consistent drought resistance performance in different appraisal periods, and could be selected as the existing drought resistant strains in test materials, including:(strong drought resistance) Four-4112, 81162, 8723, Zhong-128,Guma-4404, D34, GS04(030), F8276, S121, K10, W9813, P014, H299, V76-1;(moderate drought resistance) HCL645, C8605-2, 666, Liao-3180. |
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