SRAP Molecular Marker In The Round Shape Trait Of Cucumber Fruit

The fruit-shape of cucumber was one of important appearance trait. With the changes of consumption concept, the characteristic cucumber was preferred by most people. The study was focused on the molecular markers about round shape trait of cucumber fruit to provided the theoretical basis to the Molecular Marker-assised Breeding about round shape of cucumber fruit.A F2 population which has 130 individuals was produced by a cross B-2-2×Y-3. The method of BSA and SRAP markers were used to study the molecular markers on the round shape of cucumber fruit, The main results are as follows:The data of fruit shape was changed continuously, it showed that there was a normal distribution in the F2 population. The DNA of cucumber was extracted using the method of improved CTAB, It showed that the DNA extracted by this way was integrity and had a higher quality after the detection of 1% agarose gel electrophoresis.A stable SRAP system was established, in which 2.0 mmol/L Mg2+, 0.5 UTaq polymer- ase, 30 ng DNA template, 0.96μmol/L primer and 200μmol/L dNTP were included, the total volume of reaction system was 12.5μL.A total of 380 SRAP primer combinations were initially screened using two parents, of which 184 showed polymorphism between two parents and the rate of polymorphism was 48.4%.The round shape DNA pool and long shape DNA pool were constructed, and the 184 primer combinations were screened between two gene pools. It showed that there were 34 primer combinations to produce the clear and stable bands among 184 primer combinations, the rate of polymorphism was 18.5%, and there were 5 primer combinations to be found among the 34 ones after detection using the DNA of individuals which composed the gene pool.There were 3 primer combination were selected after detection using the F2 individuals DNA. and accordance rate of seperation between trait and polymorphism was 80%. It was considered that these SRAP markers were linked with round shape of cucumber fruit. The correlation analysis showed that the correlation coefficient between ME21/EM18 and the fruit shape index was﹣0.183, the correlation was significant, ME8/EM14 and ME9/OD3 was closer to the significant level of 5%. It was concluded that the ME21/EM18 marker was perhaps linked to the round-fruit gene.