Evaluation of anther-derived, inbred, and hybrid populations of Streptocarpus X hybridus Voss

Abstract

The potential of inbreeding and selective hybridization, along with anther culture, for increasing homogeneity with 2 early flowering cultivars of Streptocarpus X hybridus was examined. A 'Concorde' and 'Mixed Nymph' genotype expressed inbreeding depression within 2 generations, characterized by a reduction in corolla, leaf, and peduncle size, as well as an increase in floral deformities (flower part fusions). Inbred populations contained individuals which resembled the parent cultivars for several morphological traits. Such could be selected by cluster analysis of important traits, for the development of inbreeding depression resistant lines for hybrid production of more uniform, seed-propagated Streptocorpus cultivars. Reciprocal differences were observed among hybrids of first-generation inbreds, suggesting that female parent selection is critical for certain ornamental traits such as corolla size and peduncle length. Plants were regenerated from anther-derived callus of ‘Concorde’ and 'Mixed Nymph'. The plants were found to be of somatic cell origin, but exhibited somaclonal variation for overall morphology. Variation for leaf variegation and morphology, days to flowering, flowers per peduncle, peduncle length and leaf area were observed among progeny of anther-derived plants, indicating that heritable somaclonal variation in Streptocarpus may be exploited for increased genetic diversity for cultivar development.