Question

Define the terms hybridisation and photo-period.

Answer 1

Hint:- To improve the quality of crop or to induce the desired characteristics of two genetically different individuals, we often use the process of hybridisation. Photoperiod, on the other hand, is the length of the day or the daily illumination period received by an organism and mainly discussed for its effect on the plant development.

Complete Answer:-
Hybridisation- As said earlier, the process of combining the characteristics of two genetically unlike individuals to produce an organism or offspring, known by the term hybrid, is called hybridisation. It is accomplished by the crossing over of two target individuals and may be artificial or natural.
Hybridisation objectives-
Creation of variable population artificially so that the types with the combination of desired characteristics can be selected.
Exploitation and utilisation of the hybrids for human welfare.
 Types of hybridisation-
 Intra-varietal, intervarietal/ interspecific hybridisation, interspecific / intergeneric and introgressive hybridisation are the major types of hybridisation.
Process of hybridisation (in plants)-
Selection of parents
Artificial self- pollination or selfing of parents
a. Emasculation
b. Bagging
c. Tagging
d. Crossing
e. Raising and maintaining the F1 generation.

Photo- period- The length of day or the daily illumination period received by any organism is called photoperiod. It is often discussed for its effect on flowering and development of plants.
On the basis of photoperiodism, plants are mainly classified into three types-
Short- day plants- Also known as long- night plants and they are incapable to flower when nights are short or even in the pulse of artificial light for a prolonged period in night.
Long- day plants- They require longer day duration above critical photoperiod for flowering.
Day- neutral plants- They depend on other factors such as the development stage they are in and certain environmental stimuli such as vernalization, etc.


Note:- It is noteworthy to mention that hybridisation does not alter genetic constituents, rather it results in the new combination of genes. It is often used for the crop improvement programmes.
Many flowering plants have photoreceptor proteins such as phytochromes and cryptochromes, which they utilise to sense the change in photoperiod.