Hybridization technique, Artificial hybridization process
Parent selection: The first step in hybridization is parent selection. Care should be taken while selecting the parent that the plant should be healthy, vigorous, disease free and of improved variety. Parents are selected from local varieties that have the desired traits. If the intended parent is not born locally, it is procured elsewhere or from abroad.
Self fertilization: If the parent is not self-fertilized, self-fertilization is done by artificial means. In this the parent plant is homozygous. If the parent is homozygous, the desired trait can be matched.
Emasculation: Emasculation is the removal or killing of stamens from flowers before maturity. Only flowers of both sexes are emasculated. The purpose of emasculation is to stop self-pollination. 48-53 degrees C for those plants whose flowers are very small. Emasculation is done by immersion in water at room temperature for 1-16 minutes. Flowers of plants like paddy, wheat, bhutra etc. are emasculated by dipping them in hot water or alcohol.
Bagging: Plants selected for cross are covered with polythene bags. This is called bagging. Bagging prevents unwanted pollination. The bag is kept on the mother plant until fruiting. If necessary, very fine holes are made with a needle to allow air to pass through.
Crossing: Pollen is collected from the bagged male plant and deposited into the ovary of the bagged emasculated female plant. Two sperms are formed from the pollen. Sperm enter two follicles. In the embryo, one of the two sperm fuses with the egg and the other fuses with the secondary nucleus. The union of sperm and ovum is called fertilization and the union of sperm and secondary nucleus is called triploidy. Nishek and Trimilan together are called Bi-Nishek.
Labeling: The date of emasculation, the date of crossing and the identity of the male and female plants are written on a piece of paper and affixed to the female plant. This is called labeling.
Seed collection: The seeds obtained as a result of hybridization are called hybrid seeds. The seeds are collected after the fruits mature. After collection the seeds are cleaned. Immature seeds are discarded. Mature, developed, pure and clean seeds are packaged. It is then stored in a specific location.
Sowing of seeds and generation of F1 plant: The saved seeds are sown the following year. The resulting plants are called F1 progeny. The F1 progeny is a hybrid of the parents. In the F1 progeny, seeds were collected after fruit maturity. After collection the seeds are cleaned. Mature, developed, pure and clean seeds are packaged. It is then stored in a specific location.
Use of F1 progeny and creation of new varieties: F2 progeny is created by crossing two plants of F1 progeny. Later progeny like F3, F4, F5, F6 etc. are created. Thus a new variation is created in 7-10 years.