Effects Of Calcium Oxide And Fungicides On Peanut Disease Resistance And Rhizosphere Soil Microbial Diversity

In order to explore more green and efficient peanut disease resistance technology,Xianghua 2008,the main large seed peanut variety in Hunan Province,was selected to explore the effects of three kinds of fungicides,including calcium oxide（mineral fertilizer and fungicide）,Trichoderma harzianum（biological bacteria）,thiophanate-methyl,thifluzamide and fludioxonil（chemical fungicide）,on peanut growth and development,disease resistance,soil rhizosphere microorganisms,yield and quality.The field and indoor experiments were conducted to find out the effect.The research structure shows that:（1）In addition to Trichoderma harzianum seed dressing,other treatments can promote the number of branches;basal application of calcium oxide can increase the leaf area of a single plant from the needle setting stage to the full fruit stage,and increase the SPAD value in the early growth stage and full fruit stage;Trichoderma harzianum seed dressing can increase the leaf area of a single plant in the early growth stage;thiophanate-methyl seed dressing can promote the leaf area of a single plant in the pod setting stage and full fruit stage;thiophanate-methyl seed dressing can increase the leaf area of a single plant in the early growth stage.The results showed that the increase of leaf area per plant and dry matter accumulation was much higher than that of other treatments at different stages;fludioxonil seed dressing increased leaf area per plant at early growth stage,the SPAD values of three chemical fungicides decreased,and the leaf color of peanut plants became lighter.（2）The results showed that calcium oxide,Trichoderma harzianum and thifluzamide could reduce the disease index of brown spot at all stages,except for Trichoderma harzianum at full fruit stage,other treatments significantly reduced the disease index of brown spot;for the control of scorch spot,the disease index of scorch spot treated with thifluzamide was lower than that of other treatments,and the control effect was better than that of other treatments;at pod setting stage,the disease index of calcium oxide,Trichoderma harzianum seed dressing and thifluzamide were lower than other treatments,and their preventive effect was better than other treatments.The incidence rate of sclerotium blight in each stage was less than that in the control,and the control effect of thifluzamide was better than that of other treatments.（3）The results showed that seed dressing with thifluzamide and fludioxonil could increase the yield of peanut,but the pod yield of other treatments decreased;in terms of quality,seed dressing with calcium oxide and Trichoderma harzianum could increase the content of oleic acid and the ratio of oleic acid to linoleic acid,and improve the quality of peanut,while seed dressing with thiophanate-methyl,thifluzamide and fludioxonil could reduce the ratio of oleic acid to linoleic acid.（4）The results showed that Ca²⁺and OH^-ions in calcium hydroxide had antibacterial effect,and the antibacterial effect of hydroxyl ion is stronger than that of calcium ion;Trichoderma harzianum and three kinds of chemical fungicides showed different antibacterial effect,and the antagonistic effect of Trichoderma harzianum on three kinds of pathogens was more than 50%,the highest was the inhibitory effect of Trichoderma harzianum on sclerotium candidum;thiophanate-methyl on sclerotium candidum and Aspergillus niger The virulence of thiophanate-methyl to Aspergillus flavus was much lower than thiophanate-methyl to Aspergillus flavus,and the virulence of thifluzamide to sclerotium albicans was the strongest,while the virulence of fludioxonil to three pathogens was high,and the virulence activity to Aspergillus flavus was the best.（5）With the change of the growth period,the diversity of bacteria and fungi decreased gradually.Calcium oxide and Trichoderma harzianum treatments could effectively enhance the diversity of the bacterial community in rhizosphere soil.The OTUs number and Shannon index of bacteria in basal application of calcium oxide and Trichoderma harzianum seed dressing compared with those of the other three chemical fungicides.The diversity of fungi in rhizosphere soil in each treatment was stopped.The Shannon index and Chao1 index of Trichoderma harzianum seed dressing and basal application of calcium oxide opposed to those of the other three chemical fungicides Learn about fungicides.（6）There were different in microbial and fungal community structure among different treatments.At the phylum level,the dominant phylum includes Proteobacteria and Undefined bacteria,Crenarchaeota,Archeobacteria and Chloroflexi,from seedling stage to maturity stage,the relative abundance of acidobacteria in fludioxonil treatment group was significantly higher than that in other treatments,the relative abundance of cyanobacteria in calcium oxide treatment group was significantly increased and higher than that in other treatments,and the relative abundance of Candida Nitrosotalea in thiophanate methyl treatment group was significantly higher than that in other treatments,the relative abundance of unidentified Chloroplast increased significantly in Cao treatment,and Burkholderia was more abundant in thifluzamide treatment than other treatments.The dominant fungi are Ascomycota,Basidiomycota,Chytridiomycota,Glomeromycota and Rozellomycota.The prevailing species that play an essential role in diverse treatments and different growth stages are different.There were more bacteria with statistical differences among calcium oxide treatment at mature stage,thifluzamide treatment at seedling stage and thiophanate-methyl treatment at seedling stage,while there were more fungal species with statistical differences among fludioxonil treatment at seedling stage,calcium oxide treatment at seedling stage and Trichoderma harzianum treatment at mature stage.