Fruit Science (Pomology)

Hormonal regulation of flowering in mango (Mangifera indica):

• Ethephon (2-chloroethylphosphonic acid, an ethylene releasing compound) sprayed at $200\text{ ppm}$ along with urea promotes early flower bud differentiation and stimulates early flowering in off-year or irregular bearing mango varieties.
• Gibberellic acid ($GA_3$) strongly inhibits flowering in mango and promotes vegetative flushing.
• Indole-3-acetic acid (IAA) is an endogenous auxin not commercially used for floral induction in mango.
• Indole-3-butyric acid (IBA) is exclusively used for root initiation in cuttings and air layering.
  
  Option breakdown:
• Ethephon is widely recommended to trigger flowering and overcome biennial bearing.
• GA inhibits flowering in mango.
• IAA does not trigger early flowering.
• IBA is a rooting agent.

• Correct Answer: Japanese plum (Prunus salicina).
• Santa Rosa is the leading commercial variety of Japanese plum grown extensively in the temperate regions of Himachal Pradesh and Uttarakhand.
• Bred by legendary plant breeder Luther Burbank in California, it is diploid ($2n=16$), highly productive, partially self-fruitful, and produces large crimson-red fruits with golden yellow sweet flesh.
• European plums (Prunus domestica) are hexaploid ($2n=48$) and include varieties like Victoria, President, and Stanley.

• Correct Answer: Tatura Trellis.
• Developed at the Tatura Horticultural Research Station in Victoria, Australia, the Tatura Trellis is a specialized V-shaped canopy support system ($60^\circ$ angle between limbs) designed specifically for high-density peach and stone fruit orchards.
• It maximizes sunlight interception throughout the canopy, facilitates mechanical pruning and harvesting, and produces extraordinarily high yields of premium quality fruit.