Fruit Science (Pomology)

• Correct Answer: Sunrise Solo × Pink Flesh Sweet.
• Surya is a gynodioecious, high-yielding papaya hybrid bred at ICAR-Indian Institute of Horticultural Research (IIHR), Bengaluru.
• It was developed from the cross Sunrise Solo × Pink Flesh Sweet.
• It bears medium-sized ($600\text{--}800\text{ g}$) fruits with deep pink/red firm, sweet flesh ($13.5\text{--}15^\circ\text{Brix}$) and excellent shelf life.

• Correct Answer: Poncirus (Poncirus trifoliata).
• Unlike all other evergreen members of the Aurantioideae subfamily, Poncirus is completely deciduous (sheds leaves in winter) and exhibits exceptional freeze hardiness, tolerating freezing temperatures down to $-26^\circ\text{C}$.
• Because of this trait, it is extensively used as a dwarfing and cold-hardy rootstock for citrus.

• Correct Answer: Periclinal chimera.
• In shoot apical meristems consisting of histogenic layers ($L_I, L_{II}, L_{III}$):

  1. Periclinal chimera: Mutation affects one or more entire concentric cell layers across the apex (e.g., mutated $L_I$ covering unmutated $L_{II}$ and $L_{III}$). These are exceptionally stable upon vegetative propagation.
  2. Mericlinal chimera: Mutated cells occupy only a part/sector of one layer.
  3. Sectorial chimera: Mutated cells occupy a wedge-like section across all cell layers.