Answer: (3) (A) is correct but (R) is not correct

Embryo rescue is indeed a technique involving embryo culture to save developing plant embryos, but its primary objective is to prevent embryo abortion in incompatible crosses, not rescue from the egg cell itself.

Option Breakdown

(1) Both (A) and (R) are correct and (R) is the correct explanation of (A)
Both statements appear true at first glance, and (R) seems to explain (A). However, (R) inaccurately describes the objective—rescue occurs post-fertilization from the seed/ovule, not “from the egg cell,” making this incorrect.

(2) Both (A) and (R) are correct but (R) is NOT the correct explanation of (A)
(A) is correct: Embryo rescue uses embryo culture. (R) is mostly correct in intent but flawed—”developing embryo from the egg cell” misstates the process, as embryos develop after fertilization within the seed, not directly from the unfertilized egg.

(3) (A) is correct but (R) is not correct
(A) holds: Embryo rescue employs embryo culture for hybrid viability. (R) fails: The goal is salvaging embryos from aborting seeds (e.g., interspecific hybrids), not extracting from the egg cell, which precedes embryo formation.

(4) (A) is not correct but (R) is correct
(A) is accurate, so this is wrong. Embryo rescue fundamentally relies on culturing excised embryos.

Embryo rescue technique is a cornerstone of plant biotechnology, primarily using embryo culture to save hybrid embryos at risk of abortion. This assertion reason question tests precise understanding of its application in overcoming breeding barriers.

Embryo Rescue Technique Explained

Embryo rescue involves excising immature embryos from seeds before abortion, culturing them on nutrient media to develop into viable plants. It’s vital for interspecific hybrids where endosperm failure halts development. Common in crops like wheat-rye (triticale).

• Surface sterilization of seeds.

• Micromanipulation to isolate embryo.

• Culture on MS medium with hormones like auxin/cytokinin.

• Transfer to soil after rooting.

Assertion (A) Analysis

Correct: Embryo rescue technique is used for embryo culture. The core method is direct embryo culture, though related techniques like ovule/ovary culture apply for very young stages.

Reason (R) Analysis

Incorrect: Rescue from the egg cell is wrong. The egg cell (ovum) fuses with sperm to form the zygote/embryo inside the embryo sac/seed. Rescue targets the multicellular embryo facing post-fertilization lethality, not extraction from the egg cell.

Applications in Plant Breeding

• Hybrid seed production from distant crosses.

• Shortening breeding cycles in perennials.

• Studying embryo development and dormancy.

For exams, key: Embryo rescue = culture of aborted/at-risk embryos, not egg cells.