RELATIONSHIP BETWEEN POLLEN TUBE/PISTIL IN INTERSPECIFIC CROSSES IN Nierembergia GENUS (SOLANACEAE)

Abstract

The relationship between stigma-pollen/style-pollen tube (EPETP) was studied in reciprocal interspecific crosses between N. linariaefolia, N. ericoides, N. scoparia, N. aristata, N. veitichii and N. calycina in order to identify compatible crosses to obtain hybrids as a tool for ornamental breeding programs. Pistils were collected 24 hours post-pollination (PP). The materials were examined by fluorescence microscopy and stained with aniline blue. Pollen tube growth in the pistils was evaluated based on the distance traveled by the tubes and the number of tubes in different portions of the style. The EPETP study confirmed that the inconsistency in many species that belong to the genus Nierembergia is expressed in the style, inhibiting the growth of the pollen tube at different levels of it. Crosses between N. scoparia x N. ericoides, N. aristata x N. veitichii, N. linariaefolia x N. scoparia, N. linariaefolia x N. ericoides and their reciprocals were detected as putative parents to obtain interspecific hybrids. These were the only crosses in which pollen tubes were observed penetrating the micropyle of the ovules.