Artificial hybridization is the process in which only desired pollen grains are used for pollination and fertilization.
Pollination is the process of reproduction in plants in which plants transfer pollen grains from another to stigma. Pollination can be of two types:
-
Cross-pollination
-
Self-pollination
Cross-pollination is the process when one plant pollinates a plant of another variety. The genetic material of two plants combine and the resulting seed from that pollination will have features of both varieties and a new variety will come out. Sometimes this method of cross-pollinating is intentionally used in the garden to create new varieties.
Self Pollination can be defined as the transfer of pollen from the anther of a flower to the stigma of the same flower or sometimes to that of a genetically identical flower.
For successful pollination to occur, pollen and stigma should be compatible. Incompatibility may lead to the rejection of pollen grains. This situation is undesirable, especially in commercial crop production. Therefore, artificial hybridization was developed.
Artificial Hybridization
Pollen-stigma compatibility is essential for successful pollination and fertilization. Once compatible pollen is accepted by pistil, events of fertilization proceed, whereas incompatible pollen will be rejected. This interaction where a pistol is able to recognize its pollen is the result of the long-term pollen-pistil interaction and the release of chemicals by pollen.
It is very important to understand how pollen-pistil interaction takes place in hybridization as it is one of the innovative methods of the crop production improvement program. Only the desired pollen grains are made to introduce to the stigma through pollination during the process of artificial hybridization. This process helps to avoid unwanted pollen rejection and saves time. This process helps to grow plants with the desired characteristics.
Steps in Artificial Hybridization
Hybridization involves two steps:
Emasculation
We know hybridization is the method of selective breeding. Thus, before the anthers could release pollen grains, they need to be thrown off. This step of removal of another using forceps is termed emasculation. In the case of unisexual flowers, this step is not necessary.
Bagging
Bagging is the protection of emasculated flowers from contamination by undesirable pollen grains. Here, the flower is covered in a bag, still, the flower attains receptivity. Bagging is done before the flowers are open in unisexual flowers. A female flower is completely protected from contamination by the process of emasculation and bagging. Once the flower attains stigma receptivity, the desired pollens are dusted on the stigma. This is resealed for further developments.
Hence, artificial hybridization ensures that the right type of pollen has been transferred to the stigma of the flower. In addition, the chance of fertilization is high. Through this approach, a variety of strains of crops can be developed and it improves the quality of crops with desirable characteristics.