| Chinese cabbage plays an important role in vegetable production. The objection of the research were: to construct linkage maps using RAPDs and AFLPs in F2 population derived from the cross 'B. campestris ssp. chinensis' X 'B. campestris ssp. rapifea Metzg', then locate 17 morphological traits in shoots and 3 root traits. The main results were as follows:(1) One set of stable reaction system was built. This system included: 1XPCR Buffer, 0.2mmol/L dNTP,2.0mmol/LMgC12, 2ng/ul Template DNA and l.lU/25ul TaqE. Amplification was performed using 44 cycles after 94℃ , 4min,each cycle consisting of 15s at 94℃, 30s at 40℃, 75s at 72℃.(2) Using 111 RAPD primers out of 500, we analysis the segregation and distrbution of RAPDs in parents and F2 plants. A total of 89 RAPDs marker loci were mapped to 13 linkage groups, covering 1393.8cM with an average distance of 15.6cM between loci. Approximately 17.1% of the marker loci showed segregation deviation from the Mendelian ratios.(3) Combined AFLP and silver stain technique, 51 AFLPs polymorphic marker were found in F2 population using 12 primer combinations from 64 EcoR I/Mse I primer pairs with 3 selective base. Located the AFLPs markers in the RAPDs linkage map, a total of 129 molecular marker loci were mapped to 10 main linkage groups and 2 small groups. The Likage groups span 1775.5 cM of the genome with an average marker interval of 13.7cM.(4) 49QTLs affecting 16 traits of shoots were identified in F2 plants using Mapmaker/QTLl.l software. The QTLs was associated with 8.9%-99.5% of the phenotypic variation in different traits. 2 QTLs were identified for leaf length, leaf number, leaf lateral shape and leaf color respectively; 3 QTLsfor leaf width, petiole width, petiole color and leaf wing; 4 QTLs controlling leaf pubescence, leaf shape index and number of leaf lobes; and 5 QTLs for petiole length, 6 for degree of leaf smooth.(5) The putative QTLs were identified controlling root morphology, including root length, root diameter, root shape index. 9 QTLs in 7 different linkage groups were found to control the root diameter, and 6 QTLs for root length, other 6 QTLs for root index. Individual QTL accounted for between 30.3% and 65.2% of the variation in the traits. Some of the main QTLs were common between traits showing that should be possible to modify several aspects of root morphology simultaneously.(6) F2 lines derived from the cross of turnip inbred line 'WJ974'X Chinese cabbage inbred line 'YT972' were distributed into large, middle and small pools through bulked segregate analysis. Three pools were screened using AFLP primer combinations of linked markers. Primer pairs of E-ACC/M-CAG amplified polymorphic fragments in swelling pool just like in the previous mapping population. Only a 220-bp fragment was amplified linked to root swelling genes. Now it was transfer to SCAR marker, and that may be useful for molecular assisted selection in root crops breeding.
|
PDF Full Text Request