ERUCASTRUM ABYSSINICUM X BRASSICA-OLERACEA HYBRIDS OBTAINED BY OVARY AND OVULE CULTURE

Pollen germination and pollen tube growth were studied in the cross Er ucastrum abyssinicum x Brassica oleracea. 25 per cent ovules showed po llen tube entry into the micropyle 5 days after pollination. Embryos d id not grow beyond the globular or heart-shaped stage. Thus post-ferti lization barriers prevent hybridization in this cross. Sequential cult ure of ovaries and ovules 10 days after pollination helped rescue glob ular embryos. Three hybrids were obtained. All the hybrids flowered in vitro. Pollen fertility was 6.5 per cent. Leaf esterase and peroxidas e isozymes confirmed the hybrid nature. Meiotic metaphase in the polle n mother cells showed 25 chromosomes. The presence of up to 9 bivalent s and a quadrivalent indicates high homology between the two genera. T he intergeneric hybrids have been multiplied using nodal segment cultu re. They are a source for obtaining ems cole crops and widening the ge ne pool of B. oleracea.