Development And Application Of SNP Marker In Peanut(Arachis Hypogea L.)

Peanut is one of the important cash crop, oilseed crop and edible crop in the world.Peanut plays an important role in our vegetable oil sources and food protein source, and it occupy a certain position and role in the national economy. Peanut root-knot nematode disease is one of serious diseases, which occurred in the majority of peanut production areas in China. The most effective way to reduce the damage of root-knot nematode disease on peanut is to devolop and cultivate peanut, and constructing a genetic linkage map can be used for locating resistance genes, breeding new peanut which is resistance to peanut root-knot nematode disease by molecular markers. SNP marker is a type of marker which has characteristics of a largest quantity, distribution widely in genome, fast, high-throughput of screening and detection and it is a promising molecular markers. SNP markers also have good stability, ease of genotyping, and will become one of the most common and effective molecular markers. This study is to develop SNP markers, and construct a genetic linkage map of peanut by use of molecular markers including SNP, AhMITE, SSR, SRAP,SRAP-RGA markers. The results were as follows:1. Developing and genotyping of SNP markers: Huayu 22 and 950527 used as parents,and the susceptible and resistant pools from the F2 generation were used materials for developing SNP marker. 2048 SNP markers were polymorphic between parents and 14 SNP markers were tightly linked with genes resistant to peanut root-knot nematode disease. Mass spectrometry method was used for genotyping the F2 individuals, and 10 SNP markers were eventually employed for constructing a genetic linkage map.2. Screening of polymorphic markers: the parents Huayu 22 and 950527, and two pools were screened using 822 pairs of AhMITE markers, 1210 pairs of SSR markers, 460 pairs of SRAP markers and 731 pairs of SRAP-RGA markers combination. Eventually, 76 pairs of AhMITE markers, 168 pairs of SSR markers, 25 pairs of SRAP markers and 72 pairs of SRAP-RGA markers showed polymorphism between the parents.3. Construction of genetic linkage map of peanut: 94 F2 individuals from Huayu 22 and950527 was used as mapping population, and eventually 176 markers were used for making genetic linkage map using Joinmap 4.0 software. A genetic linkage map was constructed,consisting of 128 markers onto ten linkage groups and covering a total of 331.2cM with an average distance of 2.59 cM between adjacent markers. Nunmer of markers in one linkage map varied from 2 to 93. The maximum and minimum distance of linkage group was154.7cM and 1.1cM, respectively.The maximum and minimum distance between the adjacent loci was 33.6cM and 0.1cM.4. Analysis of segregation distortion: among the 176 polymorphic markers, 95 markers(43.75%) showed the segregation distortion, and 74 segregation distortion markers(57.81%)were mapped onto the linkage groups. Among all of these segregation distortion markers, 39markers(41.05%) deviated toward male parent Huayu 22, 46 markers(48.42%) deviated toward female parent 950527, and 5 markers(5.26%) distorted to hetemzygote, 2 markers’ proportion were 1: 1: 1. The segregation distortion markers were mapped onto 5 linkage groups, and 13 segregation distortion regions were detected in 3 linkage groups.