ISSR Analysis Of Genetic Diversity And Evaluation Of Drought Resistance Of Fig (Ficus Carica L.)

In this study,ISSR molecular marker technology was used to analyze the genetic diversity and genetic relationship of 34 fig varieties and construct a clustering map.Then,according to the clustering results and biological characteristics,four representative fig varieties were selected('Bpjihon','Masui Dauphine','Chine epurple fruit','Qingpi'),treated with drought stress,through the growth and physiological and biochemical indicators,using the membership function method to drought resistance of four fig varieties The main findings of the evaluation are as follows:(1)From the 100 ISSR universal primers,9 primers with good polymorphism were screened out,107 DNA sites were amplified,80 polymorphic sites,and the ratio of polymorphic sites was 74.77%.The number of primer amplification sites was 8-15,the number of polymorphic sites was 5-14,and the average polymorphic site ratio of each primer was 74.4%.The highest polymorphic site ratio of primer UBC873 was 93.3%;(2)Genetic diversity analysis using POPGENE software showed that the average number of alleles(Na)was 1.6729,the average number of effective alleles(Ne)was 1.4022,and the average index of Nei's gene diversity(He)was 0.2316.The Shannon Information Index(I)averages 0.3447;(3)Using the NTSYSpc software to calculate the genetic similarity coefficient(GS)between the varieties of 0.6262~0.9720,the genetic similarity coefficient between the ‘Kodota' and the ‘M121' is 0.6262,which is the smallest,indicating that they are far away.The genetic similarity coefficient between ‘Orphan' and ‘Maliya' is 0.9720,which is the largest,indicating that they are closely related.The UPGMA method is used to construct the cluster map.With GS=0.8200 as the threshold,34 fig varieties are divided into 7 groups.;(4)The results of drought resistance physiology showed that with the increase of drought degree,the root activity of the four varieties increased first and then decreased;leaf relative water content(LRWC),chlorophyll content,maximum quantum yield(Fv/Fm)and actual quantum yield(Y(II))was significantly decreased(P<0.05);relative conductivity and malondialdehyde(MDA)content increased significantly(P<0.05);osmotic adjustment substance soluble sugar(SS)content increased significantly,soluble protein(SP)content 'Bpjihon' and ' Chine epurple fruit ' decreased significantly(P<0.05),the other two varieties did not change significantly,free proline(Pro)content increased first and then decreased(P<0.05)And most reached the maximum in severe drought;antioxidant enzymes superoxide dismutase(SOD),peroxidase(POD),catalase(CAT)activity increased first and then decreased,but reached The degree of drought at the maximum is different;(5)Using the membership function method to compare the drought resistance of four fig varieties: ‘Bpjihon'> ‘Masui Dauphine'> ‘Qingpi'> ‘China Purple Country'.