Comprehensive Evaluation Of Peanut Abiotic Stress Resistance During Germination And Genetic Diversity Analysis

Peanut（Arachis hypogaea L.）,as an important cash crop in China,ranks first in the world in terms of annual planting area,total output and export volume.Peanut is widely cultivated and susceptible to drought,low temperature and land salinization,resulting in decreased yield and quality.Therefore,it is of great significance to screen and identify peanut germplasm with strong stress resistance for achieving the industrial goals of high yield and stable yield,high quality and stable quality of peanut.In this study,resistance grades were evaluated for salt（0.12 mol/L Na Cl）,alkali（0.1mol/L Na HCO₃,p H=8.3）,drought（15%PEG 6000）and low temperature（2℃soaking for 72 h）stress,and RSR method was used for comprehensive evaluation.Spearman correlation analysis and typical correlation analysis were carried out between quality and stress.Ah MITE primer was used to analyze the genetic diversity of peanut materials and determine the plant hormones of peanut seeds,and analyze the relationship between the genetic diversity and seed germination and stress1.Based on principal component analysis method,salt,alkali,drought and low temperature were screened and evaluated.12 high salt resistant peanut materials,3 high drought resistant peanut materials and 2 high low temperature resistant peanut materials were screened.The comprehensive evaluation of RSR screened 9 high-resistance materials such as HY666,21S400 and 21L186,36medium-resistant materials such as HY9623,HY664 and 21L162,39 low-resistance materials such as HY9620,21S3 and HY963,and 6 stress-sensitive materials such as 21S9 and 21S712.The effects of biochemical quality of peanut seeds on germination indexes under stress were analyzed by canonical correlation analysis.High oleic acid content of peanut was beneficial to seed germination under salt stress,but not conducive to seed germination under low temperature stress.High palmitic acid content was beneficial to seed germination under salt and drought stress.High vitamin E content was beneficial to seed germination under salinity and low temperature stress.3.The genetic diversity of peanut germplasm was analyzed at the molecular level of DNA.The mean genetic distance between varieties（lines）was 0.794,and the variation range was 0.557～0.986.All the materials were divided into four groups by genetic cluster analysis,and combined with population analysis of different resistance levels,it was found that 7 of the 9 comprehensive identified high-tolerance materials were distributed in group B,5 of the 6 sensitive materials were distributed in group A,and 3 of the materials with high alkali tolerance,3 of the materials with high drought tolerance and2 of the materials with high low temperature tolerance were distributed in group B.4.The genetic diversity among populations with different resistance levels under different stress treatments was analyzed.The genetic diversity of drought and low temperature resistant materials was the highest,with Nei’s gene diversity of 0.21 and 0.23,respectively;Among the different resistance levels of comprehensive resistance,the genetic diversity of low resistance materials is the highest,with Nei’s gene diversity of 0.198.5.Correlation analysis was conducted using statistical data of germination indicators under four stress conditions and 37 Ah MITE markers.The selected markers covered all linkage groups,and a total of8 molecular markers significantly correlated with stress resistance during the bud stage were identified.The explanatory rate of phenotypic variation was 10.27%～20.8%.6.The correlation between plant hormones and peanut germination stage was analyzed.Ethylene,jasmonic acid,salicylic acid and gibberellin were significantly positively correlated with germination indexes of peanut at germination stage.As endogenous hormones,they could alleviate the damage of peanut at germination stage under stress conditions and improve the tolerance of peanut under adversity stress.