Define the tern hybridisation and photoperiod.

Explanation

Hybridisation The cross between two unidentical plant to givee rise to a new varitety with desired trait is called hybridisation . (Also refer to Q.5)
Photoperiodism the effect of light hours or daily duration of light exposure on the flowering of plant is called photoperiodism. On the basis of light duration or dark exposure plants one classified as short day plant (requires short photoperiods) or long day plants (requires long exposure of light).