नमस्कार मित्रांनो इयत्ता बारावी Biology या Subject च्या Practical मध्ये PART - B: Demonstration Experiments (Spotting) हा भाग Practical Exam च्या दृष्टीने फार महत्त्वाचा आहे. या Blog Post मध्ये आपण Spotting Practical Number 9: Demonstration of hybridization technique ह्या Practical Experiment चे Answer पाहणार आहोत. खाली दिलेल्या उत्तरांमध्ये काही अडचण असल्यास आम्हाला comment करा किंवा तुमच्या संबंधीत विषय शिक्षकांशी चर्चा करा.
B. DEMONSTRATION EXPERIMENTS (Spotting)
9. Demonstration of hybridization technique.
Introduction :-
Hybridization is one of the methods of crop improvement undertaken to combine the desired, useful characteristics from two different pure varieties of plants species, selected as male and female parents. The technique involves following steps:
a. Collection of pollen grains (Anthesis) :-
Pollen grains from flower of selected male parent are collected in sterile paper bags and are stored in clean and dry vials at cool place. Collection is done in the early hours of morning. Day, date and time of Anthesis is recorded.
b. Emasculation :-
It is the removal of young anthers of the stamens in the plant selected as female parent, having bisexual flowers, well before anthesis i.e formation of pollen grains. The bisexual flower of a female parent is emasculated. Buds are opened and stamens are removed mechanically by forceps or by giving hot water treatment. Emasculation is done to prevent self pollination. Emasculation is done in the early hours of morning. Day, date and time of emasculation is recorded.
c. Crossing :-
Pollen grains are dusted on the mature stigma of emasculated flower by opening the bag temporarily. It can also be done by brushing the pollens or pollen grains from the male parents directly on stigma of emasculated flower. Date of crossing is recorded on the tag.
d. Bagging and Tagging :-
Emasculated flowers are then bagged in polythene bags or sterile paper bags or sterile paper bags to prevent pollination by foreign pollens. This is called bagging. A 'tag' is tied to the bag. The tag carries brief information about the names of selected parent varieties and the day, date and time of anthesis, emasculation and actual crossing.
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| Fig. Emasculation |
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| Fig. Bagging and Tagging |
Questions
1. What is emasculation?
Ans :- Emasculation is the process of removing the anthers from a flower to prevent self-pollination. This is typically done in plant breeding to control cross-pollination. It ensures the plant receives pollen from a selected male parent.
2. Enlist different methods of crop improvement.
Ans :- Selective breeding, hybridization, mutation breeding, and genetic engineering are key methods to enhance crop traits like yield, resistance, and quality.
3. What is hybridization?
Ans :- Hybridization is the process of crossing two different plant varieties or species to produce offspring with superior traits from both parents.
4. What is the purpose of bagging the emasculated flower prior to artificial pollination and after artificial pollination?
Ans :- Bagging the emasculated flower prevents unwanted pollination and ensures only desired pollen fertilizes the flower after artificial pollination, maintaining controlled breeding.
5. Why is it that the anthesis, emasculation and actual crossing are perfectly done early in morning or late afternoon?
Ans :- These processes are done early in the morning or late afternoon to avoid extreme temperatures, which can affect pollen viability and fertilization success.
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