Identification Of Physiological Races Of Powdery Mildew Of Bitter Gourd In Guangxi And SNP Molecular Marker For Powdery Mildew Resistance Development

Powdery mildew is an important disease which endangers the production of bitter gourd.The most effective measures for its prevention and control are the breeding and utilization of resistant varieties,but there are still many deficiencies in the basic research on the identification of physiological races and molecular marker assisted breeding of bitter gourd powdery mildew.In this experiment,the pathogen physiological races of powdery mildew of balsam balsam were tested by 13 international general-purpose Differential Hosts and 6 special types of bitter gourd identification host,two systems were compared,and the inoculation and preservation methods of powdery mildew fungus were studied.SNP is considered to be the most potential third generation molecular marker.This study uses SLAF-seq technology to analyze the genetic separation group of bitter melon(2 parent and 30+30 mixed pool)with high resistance to powdery mildew self inbred line MCl8 and high susceptible powdery mildew self inbred line MC105 and the F2 generation of hybrid F2 leaf DNA.29 candidate loci associated with target traits were selected.Tetra-primer ARMS PCR and CAPS markers were used to develop practical SNP markers,and the reaction conditions were optimized and verified,and the germplasm resources of bitter gourd were screened.The main experimental results are as follows:1.Through the comparison and identification of two identification systems,it was preliminarily determined that the dominant race of powdery mildew of bitter gourd in Guangxi was S.fuliginea race 1 and M-4.The pathogen of powdery mildew was inoculated on the host leaves with the method of powdery spore inoculation,the disease leaf method and the suspension spore spray method.The effect of different inoculation methods on the disease of powdery mildew was observed.The results showed that the inoculation method of powdery mildew was early and heavy.Later,but the disease is uniform and easy to identify.2.Use SLAF-seq technology for commercial genetic segregation population(2 parents and 30 + 30 mix pool)correlation analysis,were polymorphism SLAF label 5502,5.99%polymorphism tag.A correlation analysis was performed on the polymorphic SLAF label to screen 29 markers associated with the target trait.3.By using the selected 29 Marker related to the target traits,the primers were designed by the online primer design software http://primerl.soton.ac.uk/primerl.html,and a total of 46 primers were designed.After optimization of amplification conditions and amplification system,the best Tetra-primer AMRS PCR reaction conditions were obtained.The optimized system was used to screen the Tetra-primer AMRS PCR primer group,and 3 groups of polymorphic Tetra-primer AMRS PCR primers in parental and F2 generation were screened.The typing results were stable and reproducible.4.Using the sequence obtained from the sequencing,the use of online enzyme sites recognition software http://helix.ustl.edu/dcaps/dcaps.html in candidate SNP arrays containing correlation Marker screening CAPS mutation loci exist,pick out the suitable enzyme,then using the primer design software Primer5.0 CAPS primer design.In the end,the optimized system was used to select Marker8515 with the enzyme cutting and amplification polymorphism,and the fractal result was stable,which could be used as the CAPS marker.