Establishment Of Evaluation System Of Salt Or Alkali-stress Tolerance In Maize And Screening Elite Maize Germplasm

Salt soil was widely distributed in the world and could affect normal growth of crops. As the global salinity accelerated, it increased the threat to humanity and became one of the ecological crisis to humanity. Salinity was inferior to drought in causing the loss of agricultural production. Jilin Province was one of corn main production areas in China. The western region of Jilin province is the salinization severity area. The salinization poses a grave threat to the development of ecological environment and economic in this region. So rapid development and effective use of saline soil is important and have practical significance to the economic benefits, environmental protection and sustainable development in Jilin Province.Under 4 alkali-stress conditions (Na2CO3 solution) and 4 salt-stress conditions (NaCl solution), maize hybrid Zhengdan958 and their parents were cultivated by sand culture. The concentration of Na2CO3 is 12.5, 25, 37.5 and 50 mmol/L, respectively. The concentration of NaCl is 50, 100, 150 and 200 mmol/L, respectively. Some physiological and biochemical indicies were tested and used to evaluate salt-alkali tolerances of hybrids and their parents, which included germination percentage, relative conductivity, SOD activity, MDA content and proline content, etc. Based on the differences between salt-alkali tolerances of hybrids and their parents the screening system of salt or alkali-stress tolerance in maize seedling were established. Salt-alkali tolerance in seedling stage among twenty-nine maize hybrids used predominantly in Jilin Province was analysised and part of these hybrids were planted in Taonan Research Center and the other in Gongzhuling Research Center. Reduction percentage analysis were carried out among fourteen hybrids so as to terrify the screening system of maize salinity we building previously. Based on the consensus analysis of Salt-alkali tolerance in lab and field for maize BC₂F₂ population, the survival seedling was marked by SSR makers and elite maize germplasm was further acquired.The main results were summarized as followed: (1) The appropriate concentration applied in germplasm screening were 25 mmol/L Na₂CO₃ and 100 mmol/L NaCl and germination percentage, relative conductivity, SOD activity, MDA content and proline content were the appropriate physiological and biochemical indices; (2) Three elite hybrids were screened ou of twenty-nine maize hybrids used predominantly in Jilin Province. The evaluation system of salt or alkali-stress tolerance in maize seedling was verified simply and effectively and could reflect the salinity of maize hybrids correctly. (3) Through agronomic investigation of six BC₂F₂ populations of maize, the results indicated that the analysis between seedling and field were consistent. Twelve BC₂F₂ lines were self-pollinated, whose recurrent parent was zheng58. Based on SSR marker, We screened the elite maize germplasm successfully.The results would lay a foundation for revealing the physiological mechanism of maize salt-alkali tolerant and screening elite maize germplasm, and provide reference for regional distribution of maize hybrids.