Correct option is D
Explanations-
Statement A - "Recombinant inbred lines and double haploid populations have high levels of genetic homozygosity."
Correct
Recombinant inbred lines (RILs) are derived through repeated selfing → high homozygosity. Double haploids (DH) are created by chromosome doubling of haploids → 100% homozygosity.
Statement B - "Gene pyramiding involves introducing different genes for resistance to a specific pest in different genotypes of a plant species."
Incorrect
Gene pyramiding is the process of combining multiple resistance genes into a single genotype, not different genotypes. The goal is to produce broad-spectrum or durable resistance in one plant line.
Statement C - "Agrobacterium strains with a disarmed Ti plasmid do not require vir genes for transfer of T-DNA."
Incorrect
vir genes (virulence genes) are essential for the T-DNA transfer process from Agrobacterium to plant cells. Even if the Ti plasmid is disarmed, vir genes must be present in trans.
Statement D - "Molecular breeding can be used for crop improvement if the trait of interest is present in naturally occurring populations of the plant."
Correct
Molecular breeding (e.g., marker-assisted selection) is used to select and breed for naturally occurring desirable traits.
Incorrect Statements - B and C
Correct answer is option d - B and C
