Breeding is the branch of biology which deals with the production of improved and new crop varieties, which are superior to exisiting varieties with several charactceristics. It helps for the production of several superior qualities originally found in verious plants crops into a single plant.
Plant breeding is the branch of biology that deals with improvement of heredity characters of crops and production of new crops with better and varieties of characters.
Some of the objectives of plant breeding is mentioned below :
The method involved in plant breeding are :
It is the process which involve in the introduction of high yielding varieties of plants from their growing locality to the new locality. It is also known as the easiest and improvement. This is simply the planting of plant growing in one place to another place. The introduce plant will adjust the new environment on its own. This adjustment is known as acclimatization.
It is the traditional method of breeding and it was only practice by man in ancient time. It is simply the technique of breeding which deals with the selection of better one from the entire crop plants. There are three method of selection –
1. Mass selection-It is the traditional and easiest method of development practiced by the farmer in ancient time.The best looking and healthy plants areselected from the entire plant in the filed and harvested for better result.This technique only depend on the external characters phenotype which involve in the improvement of local or wild varieties.
2. Pure line selection or single plant selection – In 1903, W.L. Johannes of Denmark individual obtained by selfing”.In other word pure line can be defined as a group of plants which are obtained from a single self-fertilized homozygous plant. Pure line selection is the process of selection of homozygous plant from the mixed population and multiplying them without any contamination to produce healthy offspring.
3. Clonal selection- In some plant, due to the low viability, seeds may not found. In such condition, plants use some other extra vegetative organs for their propagation. Fruits likes mango, apple, orange, they have a wide heterozygosity and have high degree of polypoidy. If such plants are propogated by seeds, they may show variation in characters which may affect the purity of race and cause low amount of production. The plant obtained by vegetative is called clone. The clone of plants are genetically identical in nature. After many years of vegetative propagation, it again shows its original characters.
It is the process which deals with the artificial crossing of to genetically different plant for producing new varieties. Hybridization mostly deal with creation of a variable population for the selection of type and with desired combination characters artificially. Many valuable characters scattered in different species, varieties can be found in a single variety containing all good characters.
The crossing over can be done within some or different species. Hybridization have following types on the basis of taxonomic relationship between parental plants involve in the group:
1.Intra-specific hybridization- This is the type of hybridization which involve in the crossing over between the same species. Usually these crosses are useful for the development of self pollination crops. Hence, it can be useful for only to maintain and improve the individual varieties.
2. Inter-specific hybridization- This is the type of hybridization which involve in the crossing over made between the plants of two different varieties of the same species. In this hybridization the desirable characters of both the parental plants can be combined. This cross can be made in both the self pollination and certain cross pollination crops. A desirable varieties of plant can be produced in this hybridization.
3. Intra- genic hybridization- This is the type of hybridization in which the crosses are made between the plants of different species of the same genus. This method is able to produce diseases and pest resistance plants.
4. Inter-genic hybridization- This is the type of hybridization which deals with the crosses that are made between two different genera of the same family. The parental plants are taxonomically distant related. Some of the example of this type of hybridization are; Triticale, Rabble, Raphanobressica, etc. This technique also produces the plants that can resist the diseases as well as pests.
Brinjal + Tomato = Bromato
Sugarcane + Sorghum = Sugarcane-sorghum
Hybridization is the one of the most useful technique that works for the welfare of human beings. Plant breeding technique also even help in the Nepal to create many new plants. It is most important for the agricultural countries such as Nepal. It helps to form new and advance plant which enhance the agriculture as well their economic status. It helps to obtain diseases and pests resistance plant which can uplift the agriculture.
The steps of hybridization procedure are as follows:
i). The parental plant must have maximum number of desirable characters.
ii). It should be healthy and vigour.
iii). It should be tested for their homozygosity.
Arvind K. Keshari,Kamak K. adhikari. A Text Book of Higher Secondary Biology. Kathmandu: Vidyarthi Pustak Bhandar, 2014.
Agrawal, sarita. principle of biology. 2nd edition . kathmandu: Asmita book Publication, 2068 ,2069
Mehta, Krishna Ram. Principle of biology. 2nd edition. kathmandu: Asmita, 2068,2069.
Jorden, S.L. principle of biology. 2nd edition . Kathmandu: Asmita book Publication, 2068.2069.
1. Hybridization is the process which deals with the artificial crossing of to genetically different plant for producing new varieties.
2. The process of removing the stamen before anthesis is known as emasculation.
3. The plant obtained by vegetative is called clone.
4. Pure line selection is the process of selection of homozygous plant from the mixed population and multiplying them without any contamination to produce healthy offspring.
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