Effect Of Ecological Conditions And Drought During Later Growth Stage On Seed Vigor Formation And Analysis Of Physiological Differences In Wheat

Seed vigor is the comprehensive expression of activity level and behavior characteristics of seed or seed lots during germination and emergence,which is an important index of seed quality.Huang-huai-hai wheat region is one of the main wheat production regions in China.Because of the different geographical environment,there are different types of ecological subregions in the wheat region.The study of seed vigor in different ecological conditions of subregion is not enough.It is significant to study the difference of seed vigor of same varieties in different ecological environments.In this study,Jimai 22,Zhoumai 18 and Shannong 23 were used as test materials,and 5 experimental locations were selected in Shandong Province for field planting of winter wheat,the Northwestern Region(Binzhou),the Middle Region(Weifang and Taian),the Jiaodong Region(Laizhou)and the Southwestern Region(Heze).By studying the effects of climatic factors,soil fertility and drought during later growth stage on seed vigor formation,the differences of seed vigor and physiological basis of wheat produced in different regions were clear,the effects of exogenous GABA on wheat seedling formation under drought stress were studied,and the optimum conditions of high vigor seed production were explored.The main findings are as follows: 1 Effects of different ecological conditions and drought during later growth stage on wheat yield and yield components.Laizhou and Weifang had the highest yield,with the highest spike number in Laizhou and the highest 1000-grain weight in Weifang.Compared with the control(normal watering),the yield of different varieties in different locations decreased with different degrees.The yield of Jimai 22 was significantly lower than that of the control under drought condition in 5 experimental locations,and the yield of Zhoumai 18 was significantly lower under drought condition in Weifang,Binzhou and Laizhou,and the yield of Shannong 23 was significantly different from that of the control only under drought condition in Taian.2 Effects of different ecological conditions and drought during later growth stage on seed vigor and physiological basis of wheat.The germination percentage of Jimai 22 was not significant in 5 locations,but the vigor index had significant difference among test locations.Jimai 22 had the highest vigor index in Laizhou and Weifang,and the lowest vigor index is in Heze.There was no significant difference in germination and vigor index between Shannong 23 and Zhoumai 18.The effect of drought during later growth stage on seed germination and vigor index varied with varieties.The vigor index of most test locations was significantly lower than that of the control.The electrical conductivity of seeds was closely related to the seed vigor of Jimai 22.The lower electrical conductivity is,the higher seed vigor is.The activities of alpha-amylase and dehydrogenase in germination of high vigor seeds were higher than low vigor seeds.3 Effects of different ecological conditions and drought during later growth stage on chemical composition of wheat grain.The results showed that the protein content of seeds produced in Laizhou and Weifang was higher than that in other locations,and the relative starch content and amylopectin content of seeds produced in Taian were higher than that in other locations.The effects of drought during later growth stage on absolute protein and relative starch content were region effect and variety effect.4 Correlation analysis of Meteorological and soil factors with seed yield,seed vigor and seed chemical composition.Effective accumulated temperature after flowering was negatively correlated with the yield of irrigated land,and maximum temperature was negatively correlated with the yield of dry land.Effective accumulated temperature ? 10 ? was positively correlated with the relative starch content of irrigated wheat.Effective accumulated temperature after anthesis was positively correlated with the relative starch content of irrigated and dryland wheat.There were significant differences in soil nutrient index among different ecological locations.The best place for soil nutrient content is Laizhou.But Weifang has low soil nutrient content.There was no significant correlation between soil nutrients and seed yield,vigor and chemical composition,but in the drought condition,available potassium had a positive promoting effect on grain weight,and there was a significant negative correlation between available potassium and germination percentage in dry land,and there was a significant negative correlation with vigor index.5 Regulation of GABA on wheat seedling formation under drought stress.The growth and seed vigor of wheat seedlings were significantly affected by drought stress.0.5 mM GABA seed soaking and exogenous spraying significantly increased the seed vigor and root length of wheat,the oxidative damage of leaves was also improved.