| Maize is the world’s largest food crop.Waterlogging stress seriously limits the high and stable yield of maize.Therefore,evaluating and screening waterlogging-resistant maize hybrids is a key way to solve the problem of maize production,which is of great significance to ensure food security in my country and the world.In this study,17 maize hybrids suitable for planting in northern Anhui were selected as the test materials.Through soil cultivation in an artificial climate chamber,normal water treatment and waterlogging stress treatment(V3 stage,flooding for 6 d)were set.Root and canopy phenotype evaluation and waterlogging resistance analysis were carried out for the varieties,and the waterlogging resistance evaluation and screening of maize varieties were carried out by principal component analysis,cluster analysis and other methods.The main findings are as follows:1.Waterlogging stress significantly affected the adventitious root length,adventitious root surface area,adventitious root volume,adventitious root number,primary root length,primary root volume and root-shoot ratio of maize plants,and significantly affected the stem diameter and plant height of maize plants.2.Under waterlogging stress,stem diameter,adventitious root surface area,and adventitious root volume were significantly positively correlated with the comprehensive ability coefficient of waterlogging resistance(D value)(P<0.01),and the correlation coefficients were 0.705,0.942,and 0.919,respectively;The values were significantly correlated(P<0.05),and the correlation coefficient was 0.580.Combining the results of variance analysis and correlation analysis,adventitious root surface area and adventitious root volume played an important role in maize waterlogging resistance.3.Through the principal component analysis and cluster analysis of the waterlogging tolerance coefficient(WTC),the 17 maize test varieties were divided into four groups:waterlogging resistant,moderate waterlogging resistant,waterlogging sensitive,and not waterlogging resistant.Based on the principal component analysis of the index(WSI),three groups were divided into three groups: waterlogging resistant,moderate waterlogging resistant,and not waterlogging resistant.According to these two different analysis objects,the same waterlogging-resistant and non-waterlogging-resistant varieties were obtained.The waterlogging-resistant variety was Longping 206,and the non-waterlogging-resistant variety was Denghai 652.4.The activities of SOD,POD and CAT in leaves of cultivars with strong waterlogging resistance were higher than those of cultivars with weak waterlogging resistance,among which the activities of SOD and CAT increased the most on average,110.2% and 149.3%,respectively.The same trend was also shown in the activity of cultivars with strong waterlogging resistance,and the average increases of SOD and CAT were 138.6% and149.3%,respectively.The increase of MDA content in leaves of cultivars with strong waterlogging resistance was smaller than that of cultivars with weak waterlogging resistance,with an average increase of 55.1% and 113.3%,respectively.To sum up,this study used the morphological and physiological indicators related to waterlogging resistance at the seedling stage of maize to identify the waterlogging resistance of 17 maize cultivars.The obtained waterlogging-resistant varieties are of great significance for the cultivation of maize stress-resistant varieties and the realization of high and stable maize yields in northern Anhui. |
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