Construction Of A General Genetic Linkage Map For Peach Using A 'Qinguang2'×'Shuguang'F₁ Progeny By SSR Markers

Peach is one of the most ancient fruit trees originated from China. Peach plays an important role in fruit production. Constructions of genetic linkage maps and locations of main agronomic traits or main genes are vital to research and use of peach germplasm resources.In this experiment, 90 F1 groups of'Qinguang2'×'Shuguang'were used to build peach genetic linkage map by SSR markers. The main results were as follows:1. Polymorphism analysis of SSRs Two parents'Qinguang2','Shuguang'were used to screen SSR primer. There were 45 pairs primers filtered out differences in 50 pairs. 104 polymorphic sites were produced in total, 2~3 polymorphic sites per pair primer in average. In the markers correspond to these104 polymorphic sites, 25 markers'separate ratio didn't meet the Mendelian ratio, they were distorted separation markers. The frequency was 24.04%.2.Construction of genetic map In the 104 SSR markers and 2 morphological markers of white/yellow flesh (Y/y) and freestone /clingstone (F/f), other than 25 distorted separation markers, 81 markers which separate ratio were 1:1 or 3:1 were used to linkage analysis by JoinMapR○3.0. A basic genetic linkage map contained 16 linkage groups, 68 makers was constructed. And then 5 distorted separation markers were added to this basic genetic linkage map.73 markers were located on the map in total, 68.9% markers were located on the map finally. There were 2~9 markers in each group, the length of linkage groups arranged 9 to 88 cM. As the average interval, the smallest was 5.5 cM, the largest was 18.5 cM. The whole length of this genetic linkage map is 640 cM, occupied 51.2% of the genome. The average length of every linkage group was 40 cM, the average interval was 11.7 cM.3. Locations of the white/yellow flesh(Y/y) morphological marker and the freestone /clingstone(F/f) morphological marker White/yellow flesh(Y/y) morphological marker and the free-stone /cling-stone(F/f) morphological marker were used to construct genetic linkage map with SSR markers. These two morphological markers were determined separately on the LG8 and LG9, their distances from the adjacent molecular markers were 4cM and 5cM.