Histological Observations on Interspecific Crosses in the Genus Lupinus

The hybridization barriers of interspecific lupin crosses were determined by histological investigations. The cross Lupinus hartwegii×L. mutabilis (both of American origin) revealed embryos in the cotyledonary stage as well as cellular endosperm. In the reciprocal combination, L. mutabilis×L. harwegii, embryo development stopped at the end of the globular stage, and simultaneously the coenocytic endosperm did no differentiate into the cellular state. In the combination L. luteus (European origin) ×L. hartwegii, embryo as well as endosperm development were initiated. Embryo development ended at any early globular stage. Twelve days after pollination the coenocytic endosperm had almost degenerated. With L. hartwegii as the female, no pollen germination could be observed.