It is possible to produce seedless tomato fruits by

1. Sexual Reproduction in Flowering Plants (basic)

To understand how plants reproduce, we must look at the flower, which serves as the primary reproductive organ. A typical flower is organized into four whorls, but the most critical for reproduction are the Stamens (male parts) and the Carpels (female parts). The stamens consist of anthers that burst to release yellow, dust-like pollen grains, which carry the male germ-cells. In contrast, the carpel is composed of a sticky stigma to receive pollen, an elongated style, and a swollen ovary at the base Science, Class VIII NCERT, How Nature Works in Harmony, p.194.

The journey of reproduction begins with pollination — the transfer of pollen grains from the stamen to the stigma. This can happen within the same flower (self-pollination) or between different flowers (cross-pollination) via agents like wind, water, or insects. Once a pollen grain lands on a compatible stigma, it travels down to the ovary to reach the ovules. Each ovule contains an egg cell. The fusion of the male germ-cell with the female egg cell is called fertilization, which results in a zygote capable of growing into a new plant Science, Class X NCERT, How do Organisms Reproduce?, p.121.

After fertilization, a remarkable transformation occurs: the zygote divides to form an embryo, the ovules develop into seeds, and the ovary ripens to become the fruit. The fruit essentially acts as a protective chamber for the seeds Environment, Shankar IAS Academy, Indian Biodiversity Diverse Landscape, p.158. Interestingly, while fertilization is the natural trigger for this growth, certain plant hormones like auxins and gibberellins can sometimes mimic this signal, allowing the ovary to develop into a fruit even without fertilization — a process that results in seedless fruits.

Plant Part	Post-Fertilization Development
Ovule	Becomes the Seed (contains the embryo)
Ovary	Becomes the Fruit (fleshy or dry protective layer)
Zygote	Develops into the Embryo

Sources: Science, Class VIII NCERT, How Nature Works in Harmony, p.194; Science, Class X NCERT, How do Organisms Reproduce?, p.121; Environment, Shankar IAS Academy, Indian Biodiversity Diverse Landscape, p.158

2. Plant Growth Regulators (PGRs): An Overview (basic)

Plant Growth Regulators (PGRs), often called plant hormones or phytohormones, are simple organic molecules that play a massive role in how a plant grows, develops, and responds to its environment. Unlike animals, plants don't have a nervous system; instead, they rely on these chemical messengers to coordinate activities. These substances are typically synthesized in one part of the plant (like the shoot tips) and then diffuse to the area where they are needed to act Science, Class X (NCERT 2025 ed.), Control and Coordination, p.108.

Broadly, we categorize these regulators into two groups based on their function: Growth Promoters and Growth Inhibitors. Promoters like Auxins, Gibberellins, and Cytokinins drive activities like cell division, enlargement, and flowering. For instance, Auxin is responsible for phototropism—the process where a plant bends toward light by elongating cells on the shaded side of the stem Science, Class X (NCERT 2025 ed.), Control and Coordination, p.108. On the other hand, Inhibitors like Abscisic Acid (ABA) act as a "brake" system, signaling the plant to stop growing or to wilt leaves during stressful conditions to conserve resources.

The concentration of these hormones is tightly regulated by the plant's genetics. For example, a gene provides the information to make a specific enzyme; if that enzyme works efficiently, the plant produces more of a specific hormone (like Gibberellin), leading to a tall plant Science, Class X (NCERT 2025 ed.), Heredity, p.131. Understanding this balance is key to mastering plant physiology.

Hormone Type	Primary Function	Key Example
Promoter	Cell division, stem growth, and fruit development.	Cytokinins: Found in high concentrations in areas of rapid division like seeds Science, Class X (NCERT 2025 ed.), Control and Coordination, p.108.
Inhibitor	Growth regulation, dormancy, and response to stress.	Abscisic Acid: Triggers the wilting of leaves Science, Class X (NCERT 2025 ed.), Control and Coordination, p.108.

Sources: Science, Class X (NCERT 2025 ed.), Control and Coordination, p.108; Science, Class X (NCERT 2025 ed.), Heredity, p.131

3. Essential Mineral Nutrition in Plants (intermediate)

Plants require a specific set of inorganic elements to grow, reproduce, and maintain their metabolism. While minerals make up a tiny fraction of a plant's total intake—as little as 0.3%—they are the "master keys" that unlock the biological potential of the remaining 99.7% of organic matter and water NCERT Class X Geography, Print Culture and the Modern World, p.105. Without these minerals, fundamental processes like photosynthesis and protein synthesis would ground to a halt.

Essential minerals are divided into two main categories based on the quantity required by the plant. Macronutrients are needed in relatively large amounts, while Micronutrients (or trace elements) are required in minute quantities Indian Economy by Nitin Singhania, Agriculture, p.302. Despite the difference in scale, a deficiency in a micronutrient like Zinc or Boron can be just as fatal to a plant as a lack of Nitrogen.

Category	Key Elements	Primary Functions
Macronutrients	N, P, K, Ca, Mg, S	Constituents of proteins, chlorophyll, and energy transfer (ATP).
Micronutrients	Fe, Zn, Mn, Cu, B, Cl, Mo, Ni	Act mostly as enzyme activators and electron carriers.

Each mineral has a specific physiological "job description." For instance, Nitrogen (N) is a core component of chlorophyll and proteins, driving vigorous vegetative growth Shankar IAS Academy, Agriculture, p.363. Magnesium (Mg) is unique because it occupies the central position in the chlorophyll molecule, making it indispensable for trapping sunlight. Phosphorus (P) is essential for energy regulation, while Sulphur (S) is a critical part of amino acids that build plant proteins Shankar IAS Academy, Agriculture, p.363.

Sources: Contemporary India II: Textbook in Geography for Class X, Print Culture and the Modern World, p.105; Indian Economy by Nitin Singhania, Agriculture, p.302; Environment by Shankar IAS Academy, Agriculture, p.363

4. Genetic Modification vs Hormonal Induction (intermediate)

In the world of plant physiology, we often look for ways to enhance crops—whether making them pest-resistant or producing convenient seedless fruits. There are two distinct scientific paths to achieve these results: Genetic Modification (GM) and Hormonal Induction. Understanding the difference is crucial because one changes the plant's internal blueprint, while the other simply influences its growth behavior externally.

Genetic Modification involves Genetic Engineering, where the plant’s DNA (the molecule encoding all genetic information) is directly altered. This is usually done by inserting a foreign gene (transgene) into the plant to provide it with traits it wouldn't naturally have, such as a longer shelf life or resistance to specific bacteria Indian Economy, Vivek Singh (7th ed. 2023-24), Agriculture - Part II, p.342. In India, this is a highly regulated field; the Genetic Engineering Appraisal Committee (GEAC) must approve any GM crop before it reaches the field. Currently, BT Cotton is the only commercially permitted GM crop in India Indian Economy, Nitin Singhania (ed 2nd 2021-22), Agriculture, p.301.

In contrast, Hormonal Induction is a physiological technique that does not alter the DNA. In a natural cycle, a flower must undergo pollination and fertilization (the union of male and female gametes) to produce a zygote, which becomes the seed Science, Class VIII NCERT, Our Home: Earth, a Unique Life Sustaining Planet, p.222. However, by applying exogenous plant hormones like Auxins and Gibberellins to the ovaries of a flower, we can "trick" the plant into developing fruit without fertilization. This process is called parthenocarpy. The resulting fruit (like seedless tomatoes) is genetically identical to its parent; it has simply been chemically stimulated to skip the seed-making stage.

Feature	Genetic Modification (GM)	Hormonal Induction
Mechanism	Alters DNA/Genotype using biotechnology.	Stimulates growth using plant regulators (e.g., Auxins).
Heritability	The new trait is passed to future generations.	Temporary effect; does not change the seeds or offspring.
Regulation	Strict (GEAC in India).	Standard agricultural practice for many seedless varieties.

Sources: Indian Economy, Vivek Singh (7th ed. 2023-24), Agriculture - Part II, p.342; Indian Economy, Nitin Singhania (ed 2nd 2021-22), Agriculture, p.301; Science, Class VIII NCERT, Our Home: Earth, a Unique Life Sustaining Planet, p.222

5. Parthenocarpy: Development of Seedless Fruits (exam-level)

To understand Parthenocarpy, we must first look at the traditional biological sequence of fruit development. In most plants, fruit formation is a response to pollination and fertilization. Once the pollen fertilizes the ovule, the plant releases internal signals—specifically growth hormones—that tell the ovary to swell and ripen into a fruit. Parthenocarpy is the fascinating exception where the fruit develops without fertilization, resulting in seedless varieties. While some plants like bananas do this naturally, humans have learned to 'induce' this process in crops like tomatoes and grapes to meet consumer demand and ease food processing.

The chemical 'engine' behind this process lies in plant hormones. Specifically, Auxins and Gibberellins play a critical role in promoting growth and cell expansion. As noted in Science, class X (NCERT 2025 ed.), Control and Coordination, p.108, these hormones are growth promoters; while auxins help in stem bending and growth, gibberellins are vital for stem and fruit development. In induced parthenocarpy, farmers apply these hormones (like NAA or GA₃) directly to unpollinated flowers. This 'tricks' the plant into thinking fertilization has occurred, triggering the ovary to develop into a fleshy fruit despite the absence of seeds.

It is important to distinguish this from other plant groups. For instance, in Gymnosperms (like Pine or Cycas), there is no ovary to begin with; the seeds are 'naked' and exposed on the surface of carpels, meaning they can never produce a true fruit, seedless or otherwise Environment, Shankar IAS Academy (ed 10th), Indian Biodiversity Diverse Landscape, p.157. In Angiosperms (flowering plants), the presence of an ovary allows for the possibility of parthenocarpy. By manipulating the concentration of Cytokinins (which promote rapid cell division) and auxins, we can ensure the fruit grows to a commercial size even without the growth signals typically provided by developing seeds Science, class X (NCERT 2025 ed.), Control and Coordination, p.108.

Type	Process	Result
Natural Parthenocarpy	Occurs due to genetic factors or sterile pollen.	Seedless fruit (e.g., Banana).
Induced Parthenocarpy	Application of growth hormones (Auxins/Gibberellins).	Seedless fruit (e.g., Induced tomatoes).
Normal Development	Pollination followed by Fertilization.	Seeded fruit (e.g., Watermelon).

Sources: Science, class X (NCERT 2025 ed.), Control and Coordination, p.108; Environment, Shankar IAS Academy (ed 10th), Indian Biodiversity Diverse Landscape, p.157

6. Solving the Original PYQ (exam-level)

This question tests your ability to apply the biological concept of Parthenocarpy—the development of fruit without fertilization—to a practical agricultural scenario. Having just studied Plant Growth Regulators (PGRs), you know that the transition from a flower's ovary to a mature fruit is normally triggered by pollination. However, by mimicking these biological signals through the application of exogenous chemicals, we can induce the plant to grow fruit even in the absence of seeds. This bridges the gap between theoretical botany and applied biotechnology, a favorite theme in UPSC Science & Technology questions.

To arrive at the correct answer, (C) spraying hormones on flowers, you must focus on the mechanism of induction. Since the fruit develops from the floral ovary, the chemical trigger must be applied directly to the reproductive structures. Applying Auxins or Gibberellins to the flowers provides the necessary chemical stimulus to initiate cell division and ovary expansion. As noted in PMC8788353 and PLOS ONE, these hormones activate the exact same genetic pathways that natural pollination would, resulting in a seedless tomato that is morphologically identical to a regular one.

It is crucial to recognize the common distractor traps used in options (A), (B), and (D). UPSC often includes options involving trace elements, mineral solutions, or radioactive fertilizers to sound technically sophisticated. While these inputs are essential for the general growth, metabolism, and yield of the plant, they function as nutritional support rather than developmental triggers. They lack the specific regulatory power to bypass fertilization. Remember: minerals provide the "bricks" for growth, but hormones provide the "blueprint" and the signal to start building.