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Genetic and maternal effects on offspring fitness in Lupinus texensis (Fabaceae)
Author(s) -
Helenurm Kaius,
Schaal Barbara A.
Publication year - 1996
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1996.tb12818.x
Subject(s) - biology , outbreeding depression , inbreeding depression , offspring , selfing , genetic load , outcrossing , inbreeding , ecology , genetics , demography , population , pollen , pregnancy , sociology
Two experiments were designed to examine jointly the roles of maternal effect, genetic load, and other genetic variability at nuclear loci in determining offspring fitness in Lupinus texensis , an outbreeding annual herb. A diallel crossing design was used to generate seeds in the greenhouse. This design directly compares maternal and paternal contribution to offspring survival, growth, and flowering, and also assesses the role of genetic load because selfs are included in the crossing design. A nested crossing design was used to generate seeds at a field site. This design addresses the contribution of parental plants to their offspring under natural conditions. Maternal effects occur throughout the life cycle, but dominate the early growth of offspring in L. texensis. Inbreeding depression also occurs throughout the life cycle, but primarily affects size and survival of offspring. Overall inbreeding depression is substantial (δ = 0.66), exceeding the twofold threshold required for maintenance of an outcrossing mating system. However, lineages vary in the stages at which inbreeding depression occurs. Moreover, extreme heterogeneity was observed among lineages, with inbreeding depression ranging from negligible (δ = 0.02) to complete (δ = 1.00). This heterogeneity could allow the invasion and maintenance of selfing genotypes in natural populations of L. texensis.