This question was dropped/deleted by RPSC in the final answer key due to conflicting historical textbook sources regarding the establishment of India's first commercial fruit preservation unit (1920 in Mumbai vs earlier experimental units in 1918).

• 1918: Year cited in certain historical trade reviews.
• 1920: Widely cited year for the first commercial fruit preservation canning unit in Mumbai.
• 1922: Alternative date in regional horticultural texts.
• 1926: Date of subsequent industrial expansion.

Tetraploid (4x) lines of watermelon are created by treating the growing shoot tips of diploid (2x) seedlings with 0.2% colchicine, an alkaloid that inhibits spindle fibre formation during mitosis.

• Colchicine: Binds to tubulin dimers, halting spindle assembly and doubling chromosome number from 2x=22 to 4x=44 to breed seedless triploid watermelons.
• Silver nitrate: Ethylene action inhibitor used to induce staminate flowers in gynoecious cucurbits.
• Ethrel: Ethylene-releasing compound used to promote female flowering in cucurbits.
• Calcium chloride: Used for postharvest firming and physiological disorder management.

In ornamental and landscape gardening, when a continuous series of arches is interconnected over a pathway to support climbing flowering vines, the garden structure is called a pergola.

• Pergola: An architectural garden walk formed by connected arches providing a shaded promenade covered with climbing ornamental plants.
• Edging: Low border planting (under 20-30 cm) used to line walks, lawns, and flowerbeds.
• Arches: Single individual curved structures placed across gates or paths.
• Drywall: Stone wall constructed without mortar used in rockeries.