Maternal effects on progeny in Thymelaea hirsuta

In the evergreen desert shrub, Thymelaea hirsuta (L.) Endl., three major gender variants produce seed. 'Stable females' produce seed throughout the reproductive life of the individual, whereas the other two variants are dichogamous, producing both pollen and ovules at different times, as 'protandrous', and 'protogynous' individuals. Seed was collected from individuals of the three maternal gender phenotypes, from six desert habitats in Egypt. Seed and seedling traits (seed mass, germination, seedling emergence, growth and survival to 30 d, and to 1 yr) were examined in laboratory and botanic garden experiments. Highly significant effects of maternal habitat were observed for most of these traits. Seedling height after 30 d differed significantly between habitats and maternal gender phenotypes. Plants from saline and non-saline depressions were significantly taller than those from other sites, and progeny of females, overall, were taller than those of protandrous and protogynous seed parents. A significant interaction was observed between maternal habitat and maternal gender phenotype, for progeny height after 30 d and for per cent seed germination. We suggest that the three maternal gender phenotypes might be differentially favoured by selection.