Genetic Dissection And AFLP Analysis Of Forlige Bitterness Trait And Yellow Leaf Mutantation In Cucumber(Cucumis Sativus L.)

Cucumber (Cucumis sativus L.) is an important annual crop belonging to the Cucubit family. China is the widest area of growing cucumber and the highest total yield in the world. The quality trait is one of the important characteristics. In order to accelerate the application of our Non-bitterness cucumber breeding and use the yellow leaf mutantion as a useful marker to identify purity of F₁ hybrids, we plan to further our study of the genetic mechanism of forlige bitterness trait and yellow leaf mutantion, get the molecular markers linkage to bi gene and yellow leaf mutantion with AFLP technique. In our study, the Homozogous gynocious line 9110GT and Common floral sex selfed line 03828 were used as parental materials for further study on genetic analysis and molecular markers in cucumber. The main results were as follows:By tasting the leave, fruits of F₁, F₂, BC₁P₁ and BC₁P₂, the progeny segregation frequency of Bi and bi fit a ratio of 3:1, the backcross segregation frequency fit a ratio 1:1, the bi gene is independence inheritance ,the fruits were also bitter when the gene Bi and bi was heterozygous,.By observing the phenotype of F₁, F₂, BC₁P₁ and BC₁P₂, the result concluded the yellow leaf mutant is controlled by one pair of recessive gene, and green color is incomplete dorminace to yellow color.By investigating the parents, F₁, F₂, BC₁P₁ and BC₁P₂, loosen linkage was found between v-1 and bi, while no linkage was detected between v-1, bi with F, u ,D, Tu respectively.Amplied fragment length polymorphism(AFLP) technique with 256 primer combinations were employed to find the polymorphisms between bitterness DNA pool and nonbitterness DNA pool, and in Non-bitterness DNA pool a 150 bp specific fragment was amplified in the primer combination of TG+GCT. This marker was testified with individual DNA of the F₂ population and the band could only be amplified in the Non-bitterness plants. Linkage analysis using the software of JoinMap 3.0 indicated its genetic distance to the Non-bitterness loci was 6.43 cM, and this AFLP marker was designed as TG/GCT₁₅₀. This band was collected and sequenced to synthesize a sequence-characterized amplified region (SCAR) primer. The primer was used to amplify the individual DNAs of the F₂ population and obtained a specific band of 87bp in the Non-bitterness plants, indicating a successful conversion of a SCAR (Sequence Characterized Amplified Region) marker from AFLP one. The SCAR marker was designed as SC₈₇, and has been practically useful to the marker-assisted selection in our cucumber breeding program. With 148 RIL individuals has been used for identifying two markers, predicted precision were 95.95% and 93.24%.Based on BSA method, AFLP technique was employed to identify marker linked to cucumber yellow leaf mutation . E₂₅M_62-120 marker correlated to the V-1 locus was detected. The AFLP marker was designed as TG/CTT₁₂₀.With 148 RIL individuals has been used for identifying the marker, the marker was testified in 90 individuals which have V-1 locus, predicted precision were 99.3%.The mutant is a useful marker to identify purity of F₁ hybrids.