Phenotypic variation of F₁ and F₂ populations from three species of <i>Solanum L.</i> (Solanaceae)

Abstract

Emerging chromosome types in some Solanum species underscore inherent potentials and possible>new and expanded genome. Interspecific crosses involving the varieties of Solanum melongena L.,Solanum macrocarpon L. and Solanum aethiopicum L. were carried out to assess species phylogenetic relationships and the extent of evolutionary changes with a view to improving the agronomic characters in the hybrids. The dimensions of leaves, petals and fruits in the F1 hybrids were intermediate in values between parents while parental influence was significant in such characters as growth habit, inflorescence types and colour of flowers. Pollen viability was depressed from 97.3 – 71% in parents to 56.8 - 48.8% in the F1 and consistently lowered from 48.6 – 38.2% in the F2 hybrids but restored (63.8%) in an F₂ plant. Fruits were few on inflorescence, small sized with generally fewer seeds in the F1 (67 - 132) and F₂ (52 – 135) hybrids compared with the parents (87 – 384). A single flowered inflorescence from a cross (S. melongena ‘Melongena’ x S. aethiopicum) revealed a novel gene and possible selective ecological advantage over other hybrids. The incomplete restoration of some of the masked characters in the F₂ hybrids suggests a near-complete homogenization of parental genomes and/or chromosomal disharmony through silent genomic changes. These might have prevented sufficient chromosomal rearrangement and full homology for improved vigour in many of the F2 hybrids.