Studies On Artificial Introgression Of Genetic Material From Brassica Juncea Into Brassica Rapa

The objectives of this study were to obtain novel B.rapa by interspecifichybridization between Brassica juncea and Brassica rapa and transfer advancedcharacters from B.juncea to improve agronomic traits and broaden its geneticbase.The results were as follows:1. The hybridization combination with B.juncea as the female parent and B.rapaas the male parent was easy to harvest hybrid seeds. The hybrid F1plants (AAB,2n=28) were more similar to B.juncea and performed strong vegetative growth. Inaddition, F1plants were nearly completely sterile. The interspecific hybrids progenybetween B.juncea and B.rapa varied widely and novel B.rapa with Self-compatibletrait and pure yellow trait were obtained, which can offer material and theoreticalbasis for the genetic improvement of B.rapa.2. Through morphological investigation, pollen dyeability observation andcytology observation of interspecific hybrids progeny between B.juncea and B.rapa,BC1F3population has received124materials of novel B.rapa of introgress intoB.juncea. Because of the difference of genetic fragments of B.juncea, The novelB.rapa (AA,2n=20) with a large morphological differences, fertility has beenrestored and the pollen dyed rates greater than80%, chromosomal level had reacheda steady state.3. Analyzing B.juncea and B.rapa backcross progeny by GISH technique,3AA-B additional substitution lines and7translocation lines were obtained. Thesematerials on one hand can be used to increase the genetic diversity of Brapa andprovides neew breeding materials for genetic improvement of B.rapa inQinghai-Tibet, on the other hand can be used to study the origin and evolution of A and B genome.4. BC1F4populations obtained through interspecific hybridation betweenB.juncea and B.rapa were detected by AFLP and SSR marker technique to studygenomic Variation of novel B.rapa. The results showed that part of the A Genemechromosomes fragment and B Geneme chromosomes fragment of B.juncea werethansfered to the novel B.rapa.5. Four precocious materials and three high yield materials were found in18materials after field traits were investigated. These materials can be directly used asbreeding materials and create new varieties of suitable B.rapa breeding of theTibetan Plateau.