Question

Which of the following factor is NOT favourable for induction of staminate flowers in Watermelon ?

• A. Excessive nitrogen application
• B. High temperature condition
• C. Long day length
• D. Application of ethrel@150 ppm

Hint:

Sex expression in cucurbits is influenced by environment and hormones:
Favouring Male (Staminate) Flowers: High temperature, long days, gibberellins.
Favouring Female (Pistillate) Flowers: Low temperature, short days, ethylene (Ethrel), auxins. Ethrel releases ethylene, which promotes femaleness.

Answer 1

The Correct Option is D

Staminate flowers are male flowers. The question asks which factor is NOT favourable for their induction, meaning which factor would discourage male flower formation or promote female flower formation in watermelon.
(1) Excessive nitrogen application: High nitrogen often promotes vigorous vegetative growth. Its effect on sex expression can be complex and vary, but it doesn't typically inhibit staminate flower formation strongly; in some cases, it might initially favor maleness.
(2) High temperature condition: High temperatures generally promote the development of staminate (male) flowers in cucurbits like watermelon. This is a factor favourable for staminate flowers.
(3) Long day length: Long day conditions also tend to favor the production of staminate (male) flowers in many cucurbit species. This is a factor favourable for staminate flowers.
(4) Application of ethrel@150 ppm: Ethrel is a plant growth regulator that releases ethylene. Ethylene is known to promote femaleness in cucurbits. Applying ethrel increases the number of pistillate (female) flowers and suppresses or delays the formation of staminate (male) flowers. Therefore, ethrel application is NOT favourable for the induction of staminate flowers; it is favourable for female flowers. Thus, the application of ethrel is the factor that is not favourable for inducing staminate flowers. Application of ethrel@150 ppm