Question

The demerits of Mass Selection in self-pollinated crops include -
(A) Varieties developed by Mass selection are quite easy to identify in the seed production program
(B) It is not possible to know phenotypic superiority of the selected plants is due to genotype or environment
(C) Varieties selected through Mass selection are not as uniform as Pure-line varieties
(D) Zygosity (homozygous or heterozygous) of the selected plants is not known

• A. (A), (B) and (C) only.
• B. (A), (B) and (D) only.
• C. (A), (C) and (D).
• D. (B), (C) and (D) only.

Hint:

Although mass-selected varieties are less uniform than pure lines, their genetic heterogeneity provides them with better populational buffering, making them more stable under fluctuating environmental conditions.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Mass selection is an ancient plant breeding method where individual plants are selected from a population based on their phenotype, and their seeds are harvested and bulked together to grow the next generation.

Step 2: Detailed Explanation:
Let us analyze the limitations (demerits) of mass selection in self-pollinated crops:
- Phenotypic vs. Genotypic superiority (B): Traditional mass selection does not always include a progeny test.
Because plants are selected solely on their visual phenotype, it is difficult to determine if a plant's superior performance is due to its genetics or favorable environmental conditions. (True demerit)
- Lack of uniformity (C): Because the seeds of many different selected plants are bulked together, the resulting variety is a mixture of several different homozygous lines.
Consequently, mass-selected varieties are less uniform than single pure-line varieties developed through pedigree selection. (True demerit)
- Unknown Zygosity (D): Without progeny testing, the breeder cannot determine if a selected plant is homozygous or heterozygous at specific loci. (True demerit)
- Ease of identification (A): The statement that "Varieties developed by Mass selection are quite easy to identify" is actually a characteristic or potential merit for certification, not a demerit of the breeding method.
Therefore, statements (B), (C), and (D) represent the primary demerits of mass selection.

Step 3: Final Answer:
The demerits of mass selection are (B), (C), and (D) only, corresponding to option (D).