Identification Of SRAP Molecular Markers Linked To Gynoecious Loci In Citrullus Lanatus (Thunb.) Mansfeld

In this paper, SRAP technique was used to study the molecular markers related to gynoecious gene of watermelon. Gynoecious watermelon and monoecious watermelon were used as parents to get F1 and F2 was obtained by self-pollination of F1. 2 DNA pools of gynoecious and monoecious were built by Bulked Segregant Analysis(BSA) and 957 pairs of primers were screened. The result were as follows:1. The objective of this experiment was to investigate the inheritance of subgynoecious trait in watermelon,HC (gynoecious) and QC (monoecious) were used as the hybridized combination in this experiment to get F1 (totol 6 plants), F2(totol 275 plants) was obtained by self-pollination of F1. Female flower proportion within 25 nodes for two populations was counted(F1:6 plants; F2: 114 plants).All the plants of F l populations expressed monoecious,similar to their maIe parents;F2 populations segregated into two phenotypes of gynoecious tape and monoecious tape in a ratio of l:3 throug X2 test( P = 0.104). These results indicated that gynoecious in watennelon was controlIed by a single recessive gene.2 The leaves of watermelon were used as meterials of extracting DNA by methods of CTAB and modified CTAB,respectively.Compared DNA quality extracted by this two methods, these results suggested that the DNA extracted by methods of modified CTAB was high quality and can be used in SRAP analysis.3. Using Watermelon genome DNA as template, In this paper , and to optimize SRAP - PCR amplification system on watermelon in Taq DNA polymerase , Mg2 + ,DNA, primer and dNTPs , respectively. The optimum SRAP-PCR system (total of 15μl) was as follows: 3.0 mmol/ L Mg2 +, 0. 3μmol/ L primer, 1.0 U/μL Taq polymerase.,0.2mmol/ L dNTPs and 80ng DNA template. The program and system could meet the demands for genome SRAP marker in watermelon.4. According to the character of SRAP prime,we design 957 pairs of SRAP primer by 33 forword premer and 29 reverse premer , and using them to amplify HC (gynoecious) and QC (monoecious) respectively. Record of results,we obtain 36 pairs SRAP primer with better polymotphism which distinguish the two parents, and using them to amplify female genomic DNA pool and male genomic DNA pool respectively (Gynoecious pool and monoecious pool were built by BSA), we obtain 8 pairs SRAP primer distinguish the two pools,then,using these diversity pairs to amplify the single plant of 10 F2 plants that used built gene pools,The Results showed that 2 characteristic bands were obtained only by primer me16-em20,one characteristic bands appeared on gynoecious plants about 160bp , This SCAR markerwas designed as me16-em20160 , the other characteristic bands appeared on monoecious plants about 205bp. This SCAR markerwas designed as me16-em20205 . By the test of which primer was used to amplify the individual DNAs of the F2 population, the result indicated that this two markers could appear steadily.Linkage analysis by the software of MAPMAKER Mapmaker ( version 3.0) indicated that this genetic distance to the gynoecious loci was18.4cM and11.4cM respectively.