Which of the following is not correct for photoperiodism?

(i) Flowering response of plants to periods of day/night is termed photoperiodism.

(ii) Long day plants require he exposure to light for a period exceeding a well defined critical duration for flowering.

(iii) Short day plants must be exposed to light for a period less than this critical duration before the flowering is initiated in them.

(iv) The critical duration is same for different plants.

(v) Day-neutral plants not have any correlation between exposure to light duration and induction of flowering response.

(vi) Duration of light period and duration of dark period is not equal importance for flowering.