| The process of F1 seed vigor formation in sh2 sweet corn, cv. Chaotian 2018 and Shuxuan No. 1, was investigated. The causes of seed deterioration in sh2 sweet com cv. Chaotian 2018 and general corn cv. Suyu No. 1 during storage were studied. The genetic traits, dynamic changes of nutrition characteristics in F2 kernel of sh2 sweet corn, cv. Chaotian 2018, during milk maturation and the correlation analysis between nutrition characteristics and temperature, rainfall were investigated. Main results obtained were as follows:The length, width, thickness, volume, fresh weight and dry weight of seed increased firstly, and declined afterward during seed developmental stage. The change of seed size was similar between Chaotian 2018 and Shuxuan No.l in sh2 sweet corn during seed developmental stage. Seed length, width, thickness and volume had the highest values in 30, 26, 18 and 26 day after pollination (DAP), respectively. Seed thickness reached firstly the highest value. Seed fresh weight and dry weight reached the highest values in 26 and 38 DAP. There was a double-peak curve change in cc-amylase activity. The a-amylase activity disappeared in 38 DAP. The p-amylase activity increased firstly and then declined, it had the lowest activity in 42 DAP. The peroxidase (POD) and catalase (CAT) activities increased gradually during seed maturation, the activities rose rapidly during 34~42 DAP and reached the highest values in 42 DAP. The contents of malondialdehyde (MDA) and leachate conductivity decreased gradually and reached the lowest contents in 42 DAP. It also observed that the contents of total soluble sugars and reducing sugar declined gradually, the contents of starch and soluble protein increased gradually during seed developmental stage. The germination percentage, the energy of germination, germination index and vigor index increased gradually along with seed development and reached the highest values in 38 DAP. The time series regression analysis showed that the seed dry weight, leachate conductivity and reducing sugar content had significant effect on seed vigor. There were positive correlations between the seed dry weight and germination percentage, the energy of germination, germination index and vigor index. There were negative correlations between the seed leachate conductivity, reducing sugar content and germination percentage, the energy of germination, germination index and vigor index, respectively. Time series regression equations between seed dry weight and seed vigor, seed leachate conductivity and seed vigor, seed reducing sugar and seed vigor were developed, respectively. Seed vigor parameters in" different developmental stage of sh2 sweet com seeds could be predicted effectively.The results showed that the seed germination percentage and vigor index were declined gradually during seed storage. During storage, Chaotian 2018 seeds with sh2 gene was deterioration sensitive as compared with general com seeds of Suyu No. 1 (as control); seed deterioration at room temperature was faster than that at low temperature (4-5℃); deterioration in the seeds with low moisture content (10.9%) was slower than that with high moisture content (12.5%). The contents of leachate conductivity, total soluble sugars and nucleic acid in seed leachate during the seed storage were increased gradually, and the increased values of Chaotian 2018 seeds were larger than that of Suyu No.l seeds, the increased values of storage seeds at roomtemperature were larger than that at low temperature and of the seeds with high moisture content were larger than that with low moisture content. The POD activity of germinating embryos stored at room temperature was declined gradually, however, the activity was increased gradually during seed storage at low temperature. The CAT activity of germinating embryos in Chaotian 2018 was declined gradually, the CAT activity in Shuyu No. 1 was lower than that in Chaotian 2018 and kept stable low level during storage. After seed storage for 180 days, there was a higher MDA content in C...
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