Studies On Genetic Diversity Of Brassica Carinata And Production Of Brassica Of Hexaploid

Plant breeders lay more and more emphasis on Brassica carinata (BBCC, 2n=34) for its desirable agronomic characters. However, the limited information about the genetic diversity of B. carinata hinders its further utilization. Genetic variation among and within 110 accessions of B. carinata (traditional cultivars) were analyzed using AFLP markers along with tens of morphological markers. There were great genetic variations among accessions as well as within accessions. The accessions of B. carinata could be divided into five groups. However, the genetic classification and the geographic origin have not met well; in other words, the cultivars originated from the same region may be designate into different groups.To transfer the good agronomic characters from B. carinata to other species of Brassica genus, the 110 accessions were cross pollinated by 29 cultivars of B. rapa (AA, 2n=20) 13235 seeds were obtained from 375 interspecific combinations involving 40154 flowers. After identifying the status of interspecific hybrids morphologically as well as cytologically and molecularly, 5111 hybrid plants were produced from 326 combinations. Great differences on the interspecific crossability were found among interspecific combinations and parents. Some combinations gained hundreds of hybrids per hundred crossing-flowers and some gained few. Twenty accessions of B. carinata with high crossability had been sort out. Interestedly, sixteen of the high-crossability accessions were collected from the same place, southeast of the Great Rift Valley in Ethiopia.For those amounts of triploids (ABC), 0.1% colchicine solution was used to drop shoot apical meristems at the time of emerging 2-3 pieces of euphylla to restore their fertility. Then a gene pool with diversity of the C genome from B. carinata would be constructed based on the ABC hybrids, which could be AABBCC hexaploid after chromosome doubling. These hexaploid may gather good traits together and the desirable genes combined in the pool can be used to improve B. napus, of course, B. juncea as well.