The mating system of Sesbania sesban (L.) Merr. (Leguminosae)

  • Girma Gebremariam International Livestock Research Institute (ilri)
  • Sileshi Nemomissa Department of Biology, Faculty of Science, Addis Ababa University
  • Abebe Demissie Biodiversity Conservation and Research Institute
  • Jean Hanson International Livestock Research Institute (ilri)

Abstract

The mating system of Sesbania sesban was studied using one natural population and two cultivated populations. A large number of progeny (600) was assayed from each population for one polymorphic locus of Malate dehydrogenase (Mdh). The level of out-crossing in the studied populations ranged from 40–100%. The genotype frequencies were in agreement with those of the Hardy-Weinberg expected genotype proportions as in randomly mating populations at P < 0.05. The floral structure and the pollen shedding behaviour of the flowers of S. sesban could favour cross-pollination and/or self-pollination depending on the circumstances. Self-pollination usually occurs late in the flowering period when pollinators fail to visit the flowers. Such a “delayed selfing” facilitates out-crossing in the presence of appropriate pollinators under natural conditions, but confers a selective advantage where pollinators are limiting. The results indicated that S. sesban could be self-fertilized in the absence of pollinators or could out-cross with other heterozygous individuals in the neighboring population when suitable pollinators are available. S. sesban exhibits “facultative xenogamy” or “delayed selfing” and is a mixed mating species.

Key words/phrases: Allozymes, delayed selfing, Hardy-Weinberg equilib rium, malate dehydrogenase, mixed mating system

SINET: Ethiopian Journal of Science Vol.25(2) 2002: 177-190

Author Biographies

Girma Gebremariam, International Livestock Research Institute (ilri)
PO Box 5689Addis Ababa, Ethiopia
Sileshi Nemomissa, Department of Biology, Faculty of Science, Addis Ababa University
PO Box 3434, Addis Ababa, Ethiopia
Abebe Demissie, Biodiversity Conservation and Research Institute
PO Box 30726, Addis Ababa, Ethiopia
Jean Hanson, International Livestock Research Institute (ilri)
PO Box 5689Addis Ababa, Ethiopia
Published
2004-03-02
Section
Articles

Journal Identifiers


eISSN: 2520-7997
print ISSN: 0379-2897