Studies On The Genetic Purity Testing System Of F₁-hybrid Cultivars In Eggplant And Pepper By RAPD Technology

The materials used in the experiment were seeds of three Fi-hybrid eggplant (Jifeng 4, Jifeng 9 and Fangqie 1) and aFphybrid pepper( 1432X245) with their parent lines. We have studied the extraction methods of DNA from dry seeds and established the optimum RAPD system. Specific primers for eggplant and pepper were screened. The study aimed to establish the genetic purity testing system of the seeds as quickly as possible. The results were as follows:1. A DNA extraction method for RAPD amplification has been established: Smash the dry seeds and add ten times weight extraction buffer. The system was incubated with 80 "C for 10-60 minutes then add 1/3 volume of 3M KAc into the solution. The system was put in -20 癈 for about 20 minutes to deposit impurity. The crude extraction solution obtained by centrifuge is diluted 10 times so that it can be used as the template in the RAPD amplification.2. The RAPD reaction system suitable for the crude DNA extraction solution was established: DNA 2 u 1,10 XPCR Buffer (Mg2+18mM)2.5 u 1, dNTP(2.5mM)1.5 n 1, Taqase (5U/U 1)0.2 V-1, primers (8pmol/n 1) 1.2 u 1 or (20pmol/u 1) 0.5 u 1, total volume 25 ul.3. The primers used to identify the purity of the seeds were screened. 10 polymorphic primers have been screened out from 152 Operon random primers and 189 Sagon random primers. OPE-12 can distinguish the parent lines from hybrid of pepper 1432X245. So it can be use to identify the seed purity of this variety. S1361 and S1375 can distinguish the pepper hybrid from its maternal lines so that it can be used to distinguish true hybrids from self-contaminating progeny. SI357 can be used only to distinguish the paternal line from the hybrids and the maternal line. OPH-11 and OPZ-08 can be used to distinguish the parent lines of Fangqie 1. OPF-06 can produce different bands among parent lines and hybrid of Fangqie 1, so that it can be used to identify the hybrid seed purity. SI075, SI321 and SI356 can be used to distinguish the true hybrids from self-contaminating progeny of Jifeng 4 and Jifeng 9.4. Genetic purity was identified. The genetic purity of the FI-hybrid seeds of Fangqie 1 was 93.2 % in the field by plant traits. The genetic purity result tested by RAPDtechnology was 87.5%, with the primer OPF-06, lower than the former. By the plant traits, the genetic purity of the Frhybrid pepper 1432X245 was 92.8%, while it was 82.0% determined by OPE-121000, and 65.2% by OPE-12,500 with OPE-121000o by RAPD technology. They show that RAPD is a stricter method to identify the genetic purity of the seeds than by plant traits.