Cytogeographical distribution of the Old World «Lupinus»

Abstract

Abstract The Old World Lupinus represents a unique group of annual species characterized by special distribution pattern, chromosomal diversity, and limited morphological and enzymatic polymorphism. This group is rather heterogeneous and might be divided into two entities: One of rough-seeded related taxa and another of smooth-seeded assemblage of distinct species. These 2 entities differ in several characters: (1) Distribution (principally Mediterranean and sympatric smooth-seeded species vs. mainly subtropical and allopatric rough-seeded ones); (2) Morphology (particularly traits of corolla, pods and seeds); (3) Specific protein polymorphism (the smooth-seeded species being more monomorphic, as judged from isozyme electrophoretic patterns); (4) Alkaloid composition; (5) Chromosome numbers (averagely lower in the rough-seeded complex). Altogether, the smooth-seeded species show more resemblance to their American counterparts. It is hypothesized that the Old World Lupinus is a «polyphyletic» group: The rough-seeded species have been evolved from earlier migrations, the smooth-seeded—from later migrule(s). This hypothesis explains the basic difference in their cyto-geographical distribution. The modes of chromosomal changes could have been parallel in both groups, however, the differences in the ancestral stocks, and the nature of environmental changes since the first migrations, could have caused diverse rates and trends of differentiation and evolution, between the two groups.