Breeding and Seed Production of Ornamental Crops (2+1)

Types of Hybridization

Types of Hybridization:

• The plants or lines involved in hybridization may belong to the same variety, different varieties of the same species, different species of the same genus or species from different genera.
• Based on the taxonomic relationships of the two parents, hybridization may be classified into two broad groups: (1) intervarietal and (2) distant hybridization.
Intervarietal Hybridization

• The parents involved in hybridization belong to the same species; they may be two strains, varieties or races of the same species. It is also known as intraspecific hybridization.
• In crop improvement programmes, intervarietal hybridization is the most commonly used. In fact, it is so common that it may often appear to be the only form of hybridization used in crop improvement


Simple Cross:

• In a simple cross, two parents are crossed to produce the F1. The F1 is selfed to produce F2 or is used in a backcross programme, e.g., A x B → F1 (A x B).
Example: In gladiolus, simple cross has resulted in the development of commercially
Important hybrids:



Complex Cross:

• More than two parents are crossed to produce the hybrid which is then used to produce F2 or is used in a backcross. Such a cross is also known as convergent cross because this crossing programme aims a converging, i.e., bringing together, genes from several parents into a single hybrid. A few examples of convergent cross are described in figure.


Example: In gladiolus, three way cross has resulted in the development of commercially Important hybrids:




Cross involving four parents:



Development of hybrids in gladiolus:

• Breeding work in gladiolus was started in the year 1999 involving 11 parents in the Department of Floriculture and Landscaping , Nauni, Soaln (HP). The hybrids were evaluated and some of newly developed hybrids are:
Distant Hybridization:

• Distant hybridization includes crosses between different species of the same genus or of different genera. When two species of the same genus are crossed, it is known as interspecific hybridization, but when they belong to two different genera, it is termed as intergeneric hybridization as in orchids.