Articles
DIVERSITY STUDY AND BREEDING OF BROOMS (TRIBE OF GENISTEAE)
Article number
714_3
Pages
29 – 36
Language
English
Abstract
Up to date, genetic diversity and breeding techniques have been rarely studied on ornamental brooms (Genisteae tribe Fabaceae family). The apply goal of this work is to combine characters of horticultural interest (habit, fragrance, color, etc.) which are not associated in present cultivars.
Preliminary studies were carried out on 31 clones from the genera Cytisus, Genista, Argyrocytisus, Lembotropis. In a first step the aim was to obtain information on cytogenetic characteristics, floral biology, and on self- and cross-compatibility.
The 2C nuclear DNA amount of the different taxa was evaluated by flow cytometry, and in some cases chromosome counts on root tips.
Taxa have been classified in 3 groups according to their DNA amount: high, medium and low.
High and low groups include only few taxa, from Genista and Argyrocytisus species; at the opposite the medium group includes various species which cannot be statistically distinguished.
For compatibility studies we observed pollen tube growth in styles, using fluorescence microscopy.
Styles were sampled after self- or cross-pollinations; cross-pollinations included intraspecific, interspecific and intergeneric crosses.
Despite information mentioned in the literature, most of the pollen tubes in self-pollinations had a good progression and reached the ovules.
The fruit set of the self-pollinated flowers ranked from 0 to 25% with some seeds in each pod.
Embryos of some of these seeds have been rescued by in vitro culture.
For cross-pollinations, pollen tubes often stopped in the style, but in one third of cases several pollen tubes reached the ovary; we compared the progression of pollen tubes between the different types of crosses and could rank them on a decreasing compatibility scale: intraspecific, intergeneric, interspecific.
In all cases, no pod has developed enough to produce seeds.
Based on these data, we established an efficient method of pollination on Cytisus scoparius (stages of emasculation and pollination), which will be tested now on various species.
These preliminary results will be completed by further studies on cytogenetic, botanical diversity and heredity of characters of horticultural interest.
Preliminary studies were carried out on 31 clones from the genera Cytisus, Genista, Argyrocytisus, Lembotropis. In a first step the aim was to obtain information on cytogenetic characteristics, floral biology, and on self- and cross-compatibility.
The 2C nuclear DNA amount of the different taxa was evaluated by flow cytometry, and in some cases chromosome counts on root tips.
Taxa have been classified in 3 groups according to their DNA amount: high, medium and low.
High and low groups include only few taxa, from Genista and Argyrocytisus species; at the opposite the medium group includes various species which cannot be statistically distinguished.
For compatibility studies we observed pollen tube growth in styles, using fluorescence microscopy.
Styles were sampled after self- or cross-pollinations; cross-pollinations included intraspecific, interspecific and intergeneric crosses.
Despite information mentioned in the literature, most of the pollen tubes in self-pollinations had a good progression and reached the ovules.
The fruit set of the self-pollinated flowers ranked from 0 to 25% with some seeds in each pod.
Embryos of some of these seeds have been rescued by in vitro culture.
For cross-pollinations, pollen tubes often stopped in the style, but in one third of cases several pollen tubes reached the ovary; we compared the progression of pollen tubes between the different types of crosses and could rank them on a decreasing compatibility scale: intraspecific, intergeneric, interspecific.
In all cases, no pod has developed enough to produce seeds.
Based on these data, we established an efficient method of pollination on Cytisus scoparius (stages of emasculation and pollination), which will be tested now on various species.
These preliminary results will be completed by further studies on cytogenetic, botanical diversity and heredity of characters of horticultural interest.
Authors
V. Bellenot-Kapusta, C. Pesteil, A. Cadic
Keywords
Genisteae, ornamental plants, breeding, pollen compatibility, DNA amount
Online Articles (24)