Construction Of Molecular Linkage Map And QTL Analysis Of Cucumber Mosaic Virus Resistance In Pepper

Cucumber mosaic virus is one of most popular plant viruses in the world, and its host range is wide. It brings serious damages to agricultural production in pepper and is difficult to be controled. Since pepper is one of the most important vegetables crops in the world and in our country, breeding for CMV resistance has been already included in main target of pepper breeding in our country.In this paper, a F2 population including 146 individuals were used for research, which were derived from resistant inbred line'Perennial'and sensitive inbred line'Qie men'with good horticultural traits. Baised on screening of the SRAP and SSR primers and analyzing genotypes of the F2 population, a genetic linkage map of pepper was constructed. F3 population (4380 individuals) which derived from F2 146 individuals of selfing were used for inoculate CMV. After QTL of CMV resistance in pepper was analyzed.The results are summarized as follows:⑴426 pairs of high polymorphic SRAP primers were screened out from 495 pairs of primers between the parental lines, 35 pairs of which were used to analyze genotypes of the F2 population. 56 pairs of polymorphic were screened out from 280 pairs of SSR primers, and 36 pairs of which were used to analyze genotypes of the F2 population. A genetic linkage map of pepper was constructed based on polymorphysis of the SRAP and SSR markers in F2 population by using Joinmap3.0 software. This map consists of 13 main linkage groups, covers 830.4cM, includes 55 SRAP markers and 21 SSR markers, and average interval distance is 10.92cM , the each linkage group distance is from 0 to 152.2cM.⑵The artificial inoculations by rubbing leaves were performed to evaluate the resistance. Using the sick tobacco leaves to infect the F3 population, collect the data in the 20th day. It enabled us to compute resistance criterion in 6 levels. We got the normal distribution map through analysis the resistance variance of the F3 population. The resistance of F2 individual was computed from the average of the F3 population derived. There was no immune individual, 25 resistant individuals (disease index between 5.1 and 20), 109 tolerant individuals (disease index between 20.1 and 40.0) and 12 individuals sensitive (disease index more then 40).⑶QTL analysis of Cucumber Mosaic Virus resistance in pepper was carried out with Map QTL(4.0). Method used to detect QTL is composite interval mapping. With the threshold LOD was 3.0, three QTLs were detected on group 1,group 4 and group 7. The first QTL was between C9C10-4 and B11C16-2 makers, and its LOD was 3.78, supporting region were from 136.1cM to146.1cM. On the group 4, supporting region of another QTL was from 57.0cM to 62.0cM. Its location was within B13C10 and HpmsE072, and the LOD was 3.35. The third QTL on the group 7 which LOD was 3.73 had supported from 94.3 cM to109.3 cM. Its location was within HpmsE124 and hpms2-2. These QTLs can respectively account for 12.7%,38.8% and11.0% of total resistance variance.Results of this research would enrich molecular linkage map, offer available markers for molecular marker-assisted selection for development resistant vius varieties of pepper.