Selections And Genetic Analyses Of Hybrid Progenies Between Brassica Napus, B.rapa, B.juncea And Orychophragmus Violaceus

Intergeneric hybrids have been produced from the crosses between Brassica napus(AACC, 2n=38) cv. 'Oro', B. rapa (AA, 2n=20) cv. 'Aijiaohuang', B. juncea (AABB,2n=36) (Accession no.GJ19) and Orychophragmus violaceus (OO, 2n=24) with O.violaceus as the pollen parent. Herein, the progenies were selected for fertility andviability with selfing in several generations with cytological and molecular analysescarried out. The main results were as follow:1. The progeny plants in lower generations from hybrids between B. napus andO.violaceus were mixopliods, which had somatic cells with different chromosomenumbers. The cytology of plants became stable with the progression of generations. TheF₁₂ plants were not mixoploids and most of them had 38 chromosomes, the same numberas the female parent B. napus. Also, 20 plants with 39 chromosomes and 4 plants with 40chromosomes were obtained.2. The progenies in lower generations from hybrids between B. rapa and O.violaceus were also mixopliods and showed a wide spectrum of phenotypes. The plantscame to stability slowly with the generation advancing. Most F₁₀ plants had 38chromosomes and 1 plant with 36 chromosomes, 8 plants with 37 chromsomes, 15 plantswith 39 chromosomes and 4 plants with 40 chromosomes. These chromosome numbers ofF₁₂ plants were different from the female parent (2n=20) or male parent (2n=24). Theseprogenies should be new plant types with different chromosome complements from theintergeneric cross.3. According to maximal chromosome number of somatic cells, two types ofprogenies appeared in the lower generations of hybrids between B. juncea andO.violaceus: plants with 2n=36 and 2n＞36. But, all F₉ plants only had 36 chromosomes,as those in B. juncea.4. With genomic in situ hybridization (GISH) analysis, some plants with additionalor substituted O. violaceus chromosomes were identified in progenies of lowergenerations of hybrids between B. juncea and O. violaceus. But with generationadvancing, the GISH analysis could not resolve whole chromosome in the genomes of these three hybrid progenies. Only some fragments or chromosome arms were labeled byO. violaceus probe in the genomes of these plants.5. AFLP analysis showed that only a few DNA fragments were found in theirgenomes of higher generations of hybrid progenies between B. napus and O. violaceus orbetween B. juncea and O.violceus, and gel profiles of these plants were more similar tothose of their female parents. But in some progeny plants of hybrids between B. rapa andO. violaceus, many DNA fragments of O.vioIaceus could be found, and one plantcontained 28.4% DNA bands of O. violaceus in whole bands.6. Some phyenotypic characters of O. violaceus could be found on the plants of threekinds of progenies, such as purple stems, basal branching and serrated leaves. Theprogenies of hybrids between B. juncea and O.violaceus liked more their female parent.Those from hybrids between B. napus and O.violaceus had many differences from theirfemale parent. Those from hybrids between B. rapa and O. violaceus deviateddramaticaly from their female parents, and some plants carried some favourite agronomiccharacters.7. Fatty acid analysis showed that the compositions of these progenies from threekinds of hybrids changed greatly from those of their female parents. The B. napus cv.'Oro' had low erucic acid (3.96%), but some plants of the hybrid progenies had higherucic acid and one plant had 52.68% erucic acid in its seed oil. The B. rapa cv.'Aijiaohuang' had high erucic acid (50.82%), but some progenies had low acid and oneplants only had 0.06% erucic acid in its seed oil. The B. juncea (accession no. GJ19) had43.43% erucic acid, but one progeny had 29.72% erucic acid in its seed oil.