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

Introduction to Hybridization

Hybridization: Hybridization is the most important technique of inducing variation in floricultural crops. The mating or crossing of two plants or lines of dissimilar genotype are known as hybridization. Crossing involves placing pollen grains from one genotype, the male parent, on to the stigma of flowers of the other genotype, the female parent.

• Although natural variability is present in self-pollinated populations but is lost quickly when they are subjected to selection. Individual plant selection or pure line selection is the most common method used for the improvement of self pollinated crops.
• Continuous selection followed by multiplication of the selected lines leads to the replacement of larger variability with the pure lines. Selection also leads to restricted gene pool and may also lead to lesser adaptation of a variety over wider climatic conditions.
• In this condition new genetic variability can only be introduced by crossing two different pure lines.
• While selecting for hybridization, some precautions and prerequisites must be met with. Firstly, it is essential to prevent self-pollination as well as chance cross-pollination in the flowers of the female parent. On the other hand, it must be ensured that the pollen from desired male parent reaches the stigma of female flowers for successful fertilization. The seeds as well as the progeny resulting from the hybridization are known as hybrid or F1.
Objectives of Hybridization

• The chief objective of hybridization is to create genetic variation. For achieving this, two genotypically different plants are crossed. The genes from both the parents are brought together in F₁ resulting in a progeny that contains the genomes of both the parents.
• In floricultural crops the breeding objectives vary from crop to crop, and according to the uses yet some common objectives are; introduction of new colours, size and shape of flowers, their orientation, stem/ spike length, fragrance, resistance to insect, pest and diseases, resistance to stress etc.(discussed in chapter 3).
Hybrid Varieties

• For the production of hybrids, two genotypically different plants are crossed. In most self-pollinated crops, F₁ is more vigorous and higher yielding than the parents. Wherever it is commercially feasible, F₁ may be used directly as a variety. In such cases, it is important that the two parents should produce an outstanding F₁.