Following statements are made regarding sex determination in plants:
A. In Silene latifolia, females are homogametic (XX) and males are heterogametic (XY).
B. Papaya (Carica papaya) shows trioecy, but its sex determination is not associated with sex chromosomes.
C. All dioecious plants with separate sexes possess heteromorphic sex chromosomes.
D. Plant sex chromosomes are ancient, and their Y chromosomes are highly degenerated, much like those in mammals.
E. Unlike animals, dosage compensation is generally weak or absent in plant sex chromosome systems.
Which one of the following combinations contains all INCORRECT statements?

Correct option is B

Correct Answer:
Option (2) – B, C and D
Explanation:
A is correct: Silene latifolia is a classic plant example with an XY sex-determination system, similar to mammals.
B is incorrect: Papaya does show trioecy, but its sex determination is associated with sex chromosomes (a primitive XY system).
C is incorrect: Many dioecious plants do not have heteromorphic sex chromosomes; some have homomorphic or autosomal systems.
D is incorrect: Plant sex chromosomes are evolutionarily young, and their Y chromosomes are not as degenerated as mammalian Y chromosomes.
E is correct: Dosage compensation in plants is generally weak or absent compared to animals.
Thus, the incorrect statements are B, C, and D.
Information Booster :
· Sex determination in plants shows remarkable evolutionary diversity.
· Many plant sex chromosomes are at early stages of differentiation.
· Papaya represents an intermediate system between autosomal and heteromorphic sex chromosomes.
· Dosage compensation mechanisms are not well developed in most plants.
Additional Information (Incorrect Options):
Option 1: Incorrect because A and E are correct statements.
Option 3: Incorrect because A is correct.
Option 4: Incorrect because E is correct.