Construction Of Molecular Marker Linkage Map Of Peach

Constructing genetic map by molecular markers was one of the most exiting progresses in genetic area. Upon constructing a high-dense linkage map, it was possible to know the distances and relationships between genes, to locate new genes, to make the position of genes clear which controled the important agricultural characters, then to make out the most efficient plan of breeding, for example, the best cross combination (including most useful genes, excluding most harmful genes ), the most apt breeding program, popular scale, selection intensity and so on. Thereby, most useful genes could be combined to improve varieties. Classical genetic maps were constructed using morphological, biological, and biochemical makers, which developed slowly Due to shortage of markers' amount and poor resolving power. Molecular markers promoted the construction of genetic maps rapidly in 1980s. Nowadays, molecular marker linkage maps of several important crops , for example rice, soybean, corn, barley and so on, were constructed in respective degree.Peach originated in China. There was abundant germ resource and breeding experiences here. But it was poor in basic research, Which limited the using of resource and varieties breeding. The peach genomic plan was started up in Europe, America and Japan one after another. So far, there were several linkage maps published(but no one in china), in which the popular amount is small, and there were still many markers couldn't be located. In this article, a genetic map, composed of AFLP( Amplified Fragment Length Polymorphism),SSR( Simple Sequence Repeat) and SCAR ( Sequence Characterized Amplified Regions) markers was constructed by studying 109 p2 population derived from the cross of 'Okubo' and 'Xingjin nectarine'. Polymorphism of parents, to collect information of molecular markers, construct high-density molecular genetic map, approve the selection and breed of varieties, and promote the development of genetics and genomics of peach. The main results were as follows:(1) The stable and high efficient AFLP analysis system of peach genome DNA was established: high quality of genome DNA is a critical factor for AFLP analysis; preamplification primers combination E40/M+0 and E+0/M+1 showed no significant difference on number of band ; selective amplification primers combination E+2/M+3 and E+3/M+3 were both suitable for comparision analysis ofpeach genome. But when E primer had two selective bases, it produced more polymorphism bands . Silver-staining were used in AFLP analysis. Low cost, short time for detecting ,free of isltope contamination , long time of preserving and convenience for recovery, all proved that silver-staining was a safe and effective detecting method.(2) Linkage map of peach was constructed with AFLP, SSR, and SCAR markers in 109 F2 population derived from the cross of 'Okubo' and 'Xingjin nectarine'.Polymorphism of parentswas analysized with 128 pairs of AFLP primers, 16 SSR primers and 3 SCAR primers. The selected primers including 54AFLP, 3 SSR and 3 SCAR with rich polymorphism and steady bands were tested in progeny. 173Markers were scored , of which 44markers were skewed segregation by ?2 test.98 AFLP , 1 SSR, 3 SCAR markers were assigned to 11 linkage groups , 26 AFLP markers were unlinked. Whole length of linkage map was1402.20 cM, covering 87% of the peach nuclear genome. The longest group was 385.2 cM,composed of 25makers.The shortest group was43.2 cM .composed of 5 markers . The largest average interval of groups was group9 with internal of 35.5 cM ; while the smallest was group 7with interval of 10.38cM. The average length of 11 groups was 127.47 cM, and average interval between markers was 13.75cM . SCAR markers linked toG/g , Y/y and D/d gene were located in group3, group1, group9 respectively.Resolving power and precision of genetic maps lied on population size to a great degree. Thereby, it was important to ensure appropriate population size. In this thesis, it was 109, which was selected randomly from 350 individual plants. It concluded from Polym...