Question

A segment of nematode species differing from the rest of the species in some physiological characteristic such as pathogenicity is called:

• A. Biotype
• B. Pathotype
• C. Race
• D. Pathovar

Hint:

Nematode biotypes can develop resistance to host plants, making management challenging.

Answer 1

The Correct Option is A

Biotype:
Population with distinct biological characteristics
Same morphology but different physiology (e.g., virulence)
Other terms:
Pathotype: Subclassification based on pathogenicity
Race: Often used for fungi
Pathovar: Bacterial subspecies

Answer 2

Comparative-terminology approach:
Different groups of plant pathogens and pests use distinct terms for physiologically distinct sub-populations, even though they look alike. In fungi, such variant populations are usually called "races"; in bacteria, they are termed "pathovars"; and "pathotype" is a broader term sometimes used loosely for pathogenicity-based grouping across other organism types.
For nematodes specifically, when a population within a species is morphologically indistinguishable from the rest but differs in a physiological trait such as its ability to cause disease (pathogenicity) or its host range, the standard term applied is biotype.
Matching the organism, nematodes, to its specific accepted terminology, rather than the terms used for fungi or bacteria, gives biotype as the correct answer.