Study On Mulberry Fruit Preservation Techniques And Association Analysis Of Fruit Traits In Mulberry Species

Mulberry,a kind of fruit with high nutrition and bioactive compounds,belongs to berries.It is known as one of the best healthy fruit in the 21 st century.Pre-harvest sclerotinose and post-harvest saprophytic disease were one of the important reasons that affected the quality and yield of mulberry fruits.At present,the breeding of mulberry varieties is also the hotspot of new varieties of mulberry trees.In the present study,the research on the isolation and identification of mulberry pathogenic fungi,the effects of biocontrol microbes on the preservation and quality of mulberry,and the molecular markers of mulberry fruit traits were mainly conducted as follows.The sclerotinia sclerotiorum,collecting from the mulberry field,was cultivated in the soil for generating three different fruiting bodies.The different fruiting bodies were amplified and sequenced by fungal ITS1 / ITS4 primers,which were identified as Ciboria shiraiana,Scleromitrula shiraiana and Ciboria carunculoides,respectively.Three rot fungi were isolated from post-harvest rotten mulberry,and they were Botrytis spp,Rhizopus stolonifer spp and Mucor spp,respectively.The antagonistic activity of TR16,TR66 and BS on mulberry fungi was detected.The results demonstrated that,the space colonization abilities of TR16 and TR66 were more?50% than that of mulberry fungi,and the growth inhibition ratio of rot fungus hypha with opposite culture was 60-80%.In addition,the effects of fermentation filtrate and spore suspension of TR16,TR66 and BS on the quality of mulberry were studied.According to the results,after chitosan treated,the decay rate,weight loss rate,soluble solids and ascorbic acid content of mulberry were significantly decreased,the contents of anthocyanin,flavonoids,total phenol antioxidant and their antioxidant activities were more significantly improved than that of the control group,respectively.The biocontrol effects of Trichoderma harzianum on mulberry sclerotinose were investigated with mulberry variety of Zhongsang 5801 as a model material.The results showed that 48 strains of Trichoderma were isolated from the soil of mulberry forest,which were identified as T.spp,Pachybasium spp,Long branch spp and Meat spp,respectively.Then,20 strains were screened from 48 strains of Trichoderma spp by using confinement culture technique,which showed higher spatial competition abilities than that of mulberry sclerotium pathogen.Moreover,the inhibition effect of metabolic substance of 20 T.spp on the growth behavior of mulberry sclerotium pathogen was studied by cellophane method.Three kinds of strains with the best potential antagonism were screened to do field control effect test for mulberry sclerotinose.The result indicated that Tr16 and Tr50 showed better biocontrol effect than others.T.spp(CTS),Coronatin(COR),Phellinus igniarius polysaccharides,T.viride fermentation solution and other elicitors were sprayed before the mulberry harvest.The results indicated that these four kinds of elicitors showed some influence on the total polyphenol and the flavonoid contents,while showed not effectively influence on the content of total sugar.In addition,the results also suggested that the effect order of four kinds of elicitors on the total polyphenol of mulberry was as follows: Tr1 fermentation solution > 0.5 g/L CTS solution > 0.01 ?mol/L COR solution > 0.1 g/L P.igniarius polysaccharides solution > CK,and the effect order of four kinds of elicitors on the total flavonoids was as follows: Tr16 fermentation solution > 0.1 g/L CTS solution > 0.01 ?mol/L COR solution > 0.1 g/L P.linteus polysaccharides solution.At last,four kinds of elicitors were used to treat mulberry to study its influence on fruit storage quality.The results indicated that,with Tr1 T.virulent fermentation solution,0.1 g/L chitosan solution,0.001 ?mol/L COR solution treated respectively,the sugar content in the fruit was slightly lower than that treated with the mulberry polysaccharides.Thus,with 10 times diluted and original concentration of T.spp solution,0.1 g/L chitosan solution and COR solution treated respectively,the total flavonoid content could be maintained well.Based on abundant resources of mulberry varieties,the ISSR molecular fingerprints of 93 mulberry varieties were constructed,and their genetic diversity and genetic relationship were analyzed.In addition,the association mapping of markers and traits was also analyzed by a mixed linear model(MLM)with TASSEL software.The result revealed that 24 loci were associated with four fruit traits,and the phenotypic variation was 7.24-28.56 %(p<0.01).