Overcoming the cross-incompatibility through embryo rescue and the transfer of characters within the genus Brassica and between wild relatives and Brassica crops

Cross-incompatibility of interspecific and intergeneric hydrids, and between diploid and polyploid is described in this paper. The causes of the failure in seed development between diploid and autotetraploid Brassica campestris lay in the genome imbalance of the hybrid endosperm. Overcoming this cross-incompatibility through embryo rescue, embryo culture, ovule culture and ovary culture is described. Especially the culture conditions of ovary culture in Brassica campestris, and the production of interspecific and intergeneric hybrids among the genus Brassica is discussd. Many interspecific and intergeneric by hybrids were obtained through embryo rescue. The cytogenetics of the interspecific and intergeneric hybrids, and the crossability of the hybrid progenies were carried out in the ganus Brassica. The cytogenetics of interspecific and intergeneric hybrids showed that a few bivalent formations were always observed at the first meiotic division of the hybrids among Brassiceae. The F1 hybrids almost never had any pollen fertility but many seeds were obtained from open pollination and backcross with their parents. Gene or character transfer within the genus Brassica and between wild relatives and Brassica crops was possible by successive backcrossing.