International Journal of Horticulture, 2017, Vol.7, No.22, 180-204
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carnation (1981). There is continuous research for developing new F1-hybrid flowers. Therefore, every year new
and more attractive hybrids are being released by different seed companies in the world. Now, F1-hybrids are
available in many flowers from A (antirrhinum) to Z (zinnia).
There are constant efforts by flower breeders to produce new and more attractive hybrids. Hybrid technology has
been set up to meet the requirements of new bedding plant technology using automated system, smaller
containers, shorter crop time, energy stress, singulated seeding, etc. It is evident that India is far behind the latest
technology of F1-hybrids in flowers. Obviously, there has been no appreciation in India of the potentialities of
hybrids in flowers. Further, hybrid seed production in ornamental plants is labour intensive and has a good
potential for the employment of youth in rural and suburban areas. It may also generate gainful income by setting
up ancillary industries dealing with equipment and other facilities also.
With the favourable climatic conditions of Jammu and Kashmir, Himachal Pradesh and Punjab, commercial
production of F1-hybrid seeds for export can be attempted by seed companies and government agencies so that
the country earns a good amount of foreign exchange. Already in Punjab, some private growers have initiated the
seed production programme of open pollinated varieties of ornamental flowers for export and are thinking of
expanding this venture to hybrid seeds as well. Such export-oriented programmes are required to be promoted
and encouraged in view of the “focus thrust area” assigned to floriculture by the Agricultural and Processed Food
Products Export Development Authority (APEDA) and the Government of India. One of the pioneer companies
which has undertaken this venture is Plantsman’s Seeds, Patiala, having 250 acres under production of flower
seeds for export.
Among ornamentals F
1
hybrids are available in Antirrhinum, Ageratum, Begonia, Calceolaria, Cyclamen,
carnation, Dianthus, Geranium, Gerbera, Hollyhock, Impatiens, marigold, Nicotiana, Petunia, Portulaca, Stocks,
Verbena etc. (Table 1).
7.2 Distant hybridization
Distant hybridization is defined as the crosses between individuals from different species belonging to same
genera or to different genera. The former is called as interspecific and the latter one is called as intergeneric
hybridization. The first distant hybridization was reported in the production of hybrid between carnation
(
Dianthus caryophyllus
) and sweet William (
Dianthus barbatus
) by Thomas Fairchild in 1717. Distant hybrids
are difficult to produce due to the failure of fertilization where zygote is not formed. In many cases, zygote is
produced after fertilization but development of zygote is hindered at various stages because of the presence of
lethal genes, genotypic disharmony between the genomes of the two parental species, chromosome elimination,
cytoplasmic incompatibility and endosperm abortion. Some distant hybrids show mortality during seedling
development or even after initiation of flowering and this is attributed to the presence of lethal genes, genetic
imbalance and cytoplasmic incompatibility.
8 Achievements of Distant Hybridization in Ornamental Plants
Generally polyploids respond better to transfer genes from wild species than diploids due to the presence of
additional homologous or homeologous genomes. Due to high heterozygosity, cross pollinated species get
benefited from interspecific gene transfer from wild species. Closely related species accept gene transfer more
easily because of high homology between their chromosomes.
8.1 Rose
Popular Tea roses:
Rosa odorata
and
Rosa gigantea
Bourbon rose:
Rosa chinensis
(China rose) ×
R. damascena
(Autumn Damask rose)
Polyantha roses: Crosses of
R. multiflora
,
R. wichuriana
,
R. indica major
Damask roses:
R. phoenicia
×
R. gallica
Noisette rose:
R. chinensis
×
R. moschata
