Step 1: Understanding the Concept:
Physiological disorders are non-pathological abnormalities in plants caused by environmental factors, nutritional imbalances, or water stress.
Seed spices like fennel (Foeniculum vulgare) are highly sensitive to microclimatic variations during their reproductive stages.
Step 2: Detailed Explanation:
Sugary secretion, also known as gummosis or "gondya" in vernacular terms, is a prominent physiological disorder of Fennel.
It is characterized by the exudation of a sticky, clear, sugary liquid from the stems, branches, and developing umbels.
This sticky fluid later turns brown or black, attracting secondary saprophytic fungi that ruin the quality of the seed and make harvesting difficult.
This disorder is typically triggered by sudden changes in weather, such as high atmospheric humidity, cloudy weather during the flowering stage, or sudden fluctuations in soil moisture and temperature.
It is distinct from pathological diseases and is managed primarily by adjusting sowing dates and maintaining balanced irrigation and fertilizer application.
Step 3: Final Answer:
Sugary secretion (gummosis) is a physiological disorder of fennel, which corresponds to option (A).