Correct option is D
Let's analyze each statement one by one to determine which ones are correct:
Statement A: MAS can be used to eliminate undesirable genotypes early in the breeding program by screening plants at the seedling stage.
True: Marker-assisted selection (MAS) allows for early identification of desirable or undesirable genotypes in breeding programs, enabling breeders to eliminate undesirable genotypes early on. Screening can occur at the seedling stage before plants are grown to maturity.
Statement B: In backcross breeding programs, breeders use molecular markers to select against the donor genome to accelerate recovery of the recurrent parent genome.
True: In backcross breeding, breeders aim to recover the genetic background of the recurrent parent while introducing a specific trait from the donor parent. Molecular markers are used to select against the donor genome and select for the recurrent parent genome, speeding up the process of recovering the desired traits from the recurrent parent.
Statement C: Among different types of mapping populations, F₂ and F₂:₃ populations are immortal populations.
False: F₂ and F₂:₃ populations are not considered immortal populations. While these populations can be propagated over several generations, they are not considered immortal as their genetic makeup can change over time due to recombination. Immortal populations typically refer to populations that can be propagated indefinitely without changes in genetic composition, such as certain recombinant inbred lines (RILs) or immortalized cell lines.
Statement D: Near Isogenic Lines (NILs) can be produced by repeated self-pollination of F₁.
False: NILs are typically produced by crossing a parent with a specific trait of interest into a background plant, followed by backcrossing to the recurrent parent for several generations. After backcrossing, self-pollination is used to stabilize the line. However, producing NILs directly from repeated self-pollination of F₁ is incorrect because self-pollination alone does not lead to the production of NILs in the context of genetic backgrounds.
Information Booster
Marker-Assisted Selection (MAS): MAS is an efficient technique used to identify and select desirable traits in plants early in the breeding process, reducing the time and resources needed compared to traditional phenotypic selection.
Backcross Breeding: In backcross breeding, the goal is to introduce a specific trait from a donor parent into the genetic background of a recurrent parent. By using molecular markers, the breeder can speed up the recovery of the recurrent parent genome, ensuring that the desirable trait from the donor parent is integrated efficiently.
F₂ and F₂:₃ Populations: F₂ and F₂:₃ populations can be used for mapping, but they are not considered immortal. These populations have the potential for recombination in every generation, which can change the genetic structure over time.
Near Isogenic Lines (NILs): NILs are developed by extensive backcrossing followed by self-pollination to produce homozygous lines with identical genetic backgrounds, except for the gene or genes of interest. They are not directly produced by self-pollination of F₁ but require several generations of backcrossing.
