Past Questions — 2025

Gladiolus is a genus of perennial flowering plants that propagate vegetatively through modified underground stems known as corms. A corm is a swollen, vertical, fleshy stem base that stores nutrients to support the plant's growth and flowering in the next season. Why other options are incorrect: - b. Bulb: A bulb (e.g., Onion, Tulip) consists of a short stem surrounded by fleshy scale leaves. While similar to corms, gladioli specifically produce corms. - c. Rhizome: A rhizome (e.g., Ginger, Turmeric) is a horizontal underground stem. - d. Tuber: A tuber (e.g., Potato) is a thickened part of a stem or root used for food storage, typically lacking the organized structure of a corm.

In potato cultivation, varieties are categorized by their maturity period (early, medium, and late). 1. **Kufri Jyoti** is a widely recognized 'early maturing' variety. It is characterized by a shorter growth cycle, allowing farmers to harvest the crop sooner than medium or late varieties. 2. **Kufri Karan** and **Kufri Chandramukhi** are generally categorized as medium-maturing varieties, often bred for specific resistances (like late blight) or higher yields over a longer period. 3. **Kufri Frysona** is a medium-to-late maturing variety specifically developed for the processing industry (chips and fries) due to its high dry matter content and specific gravity. Therefore, among the given options, Kufri Jyoti is the correct choice for early maturity.

The French bean (Phaseolus vulgaris) is a widely studied legume in cytogenetics. Its somatic chromosome number is 2n = 22. This means the diploid number is 22, and the haploid number (n) is 11. Analysis of options: - Option a (18): Incorrect. This is not the chromosome number for Phaseolus vulgaris. - Option b (45): Incorrect. This is an odd number and not characteristic of the diploid state of this species. - Option c (10): Incorrect. This does not match the known cytogenetic data for French beans. - Option d (22): Correct. The established diploid chromosome number for the French bean is 22.

Heterostyly is a genetic polymorphism in which a plant species produces two or more different types of flowers (morphs) that differ in the relative lengths of their styles (pistils) and stamens. This mechanism is an evolutionary adaptation to promote cross-pollination and prevent self-fertilization. 1. **Primula (Primrose):** This is the classic textbook example of heterostyly (specifically distyly). Primula species typically have two types of flowers: 'pin' flowers (long style, short stamens) and 'thrum' flowers (short style, long stamens). This ensures that pollen from a thrum flower is more likely to land on the stigma of a pin flower, and vice versa. 2. **Petunia:** While some species show variations, they are not the primary representative of heterostyly in botanical studies compared to Primula. 3. **Gerbera:** These are composite flowers (Asteraceae) and do not exhibit the specific morphological heterostyly seen in Primula. 4. **Ageratum:** Also a member of the Asteraceae family, it does not exhibit heterostyly.

A 'Baradari' (derived from the Persian words 'bar' meaning twelve and 'dar' meaning door) is a pavilion with twelve doors or openings. It is a characteristic architectural feature of Mughal gardens, designed to allow free flow of air from all directions and to provide a shaded space for relaxation and viewing the surrounding landscape. Mughal gardens are known for their quadrilateral layout (Charbagh), water channels, and the integration of such pavilions. Why other options are incorrect: - French gardens (e.g., Versailles) are characterized by strict symmetry, geometric patterns, and grand vistas, but do not use Baradaris. - Chinese gardens focus on naturalism, asymmetry, and the symbolic use of rocks and water. - English gardens (specifically the English Landscape Garden) emphasize a romanticized, natural look with rolling lawns and clumps of trees, contrasting with the formal structure of the Baradari.

Pusa Nanha is a renowned dwarf variety of papaya developed by the Indian Agricultural Research Institute (IARI). Due to its dwarf nature (reaching a height of only about 1-1.5 meters), it is specifically designed for high-density planting and pot culture. For commercial field cultivation under high-density planting systems, the recommended spacing is 1.5m × 1.5m. This spacing optimizes the plant population per unit area while ensuring sufficient sunlight penetration and air circulation to prevent fungal diseases and ensure optimal fruit development. Spacings like 2.0m x 2.0m are typically reserved for tall, commercial hybrid varieties, while spacings below 1.5m (like 1.25m) may lead to excessive competition for nutrients and light in a field setting.

In a honey bee colony (Apis species), there are three distinct castes based on sex and function: 1. **Drones (Option b):** These are the male bees. They are haploid (develop from unfertilized eggs) and their sole primary purpose is to mate with a virgin queen to ensure the genetic continuity of the colony. They do not possess stingers or pollen-collecting apparatus. 2. **Workers (Option a):** These are sterile females. They perform all the labor in the hive, including foraging, cleaning, nursing the brood, and guarding the hive. 3. **Queen (Option c):** This is the only fertile female in the colony. Her primary role is to lay thousands of eggs daily to maintain the population. 4. **Nymphs (Option d):** This term refers to the juvenile stages of insects that undergo incomplete metamorphosis (hemimetabolous). Honey bees undergo complete metamorphosis (egg $\rightarrow$ larva $\rightarrow$ pupa $\rightarrow$ adult), so they do not have a 'nymph' stage.

Clove (Syzygium aromaticum) is a spice derived from the flower buds of the clove tree. The commercial part harvested is the immature, unopened flower bud. These buds are picked just before they open and are then dried, which gives them their characteristic nail-like appearance and strong aromatic properties due to the high concentration of eugenol. Analysis of other options: - a. Fruit: While the tree produces berries, the fruit is not the commercial spice used globally. - b. Seed: The seeds are not the part harvested for commercial spice production. - d. Leaves: Although clove leaves are used to extract clove leaf oil, the primary 'commercial part' referred to as the spice 'clove' is the flower bud.

In honey bees (Apis species), the sex determination system is known as haplodiploidy. 1. **Drones (Males):** These are developed from unfertilized eggs through a process called parthenogenesis. Because the egg is unfertilized, drones are haploid, meaning they possess only one set of chromosomes (n). 2. **Workers (Females):** These are developed from fertilized eggs (diploid, 2n). Their development into workers rather than queens is determined by their diet (they are fed royal jelly for a short time and then switched to bee bread). 3. **Queens (Females):** These are also developed from fertilized eggs (diploid, 2n). They become queens because they are fed exclusively on royal jelly throughout their larval stage. Therefore, only the drones are developed from unfertilized eggs.

Step-by-step reasoning: 1. The question asks for the causal organism of 'leaf rust' in coffee, which is one of the most economically damaging diseases of coffee worldwide. 2. Hemileia vastatrix (often spelled vestatrix in some texts) is a basidiomycete fungus that causes Coffee Leaf Rust (CLR). It manifests as yellow-orange powdery pustules on the underside of the leaves, leading to premature defoliation and reduced yield. 3. Evaluating other options: - Exobasidium vexans: This fungus causes 'Blister blight' in tea, not rust in coffee. - Fomes noxius: This is generally associated with wood decay or root rot in various tree species, not coffee leaf rust. - Ganoderma lucidum: This is a polypore fungus known as the 'Reishi mushroom' or 'Lingzhi'; it causes white root rot in various woody plants and is not the cause of leaf rust. 4. Therefore, Hemileia vestatrix is the correct pathogen.

Arka Abhed is a prominent hybrid variety of Brinjal (Eggplant) developed by the Indian Institute of Horticultural Research (IIHR), Bengaluru. It is specifically bred for resistance against the Bacterial Wilt (Ralstonia solanacearum), which is one of the most devastating soil-borne diseases affecting brinjal crops. The prefix 'Arka' is commonly used for varieties developed by IIHR. Analysis of other options: - Tomato: While IIHR has developed many 'Arka' tomato varieties (e.g., Arka Rakshak), Arka Abhed is not one of them. - French bean: These are typically developed as cultivars or hybrids by different breeding programs, not under the Arka Abhed designation. - Cow pea: This is a legume, and its breeding nomenclature differs from the 'Arka' series used for solanaceous vegetables at IIHR.

Fairy rings are distinct circular patterns of mushrooms or lush green grass often seen in lawns. They are caused by certain species of fungi (most commonly Basidiomycetes, such as Marasmius oreades) that grow outward from a central point in a radial fashion. As the fungal mycelium expands, it decomposes organic matter and releases nitrogen, which often stimulates the growth of the grass, creating a ring of darker green grass. In some cases, the fungus may kill the grass, creating a ring of dead turf. Why other options are incorrect: - Bacteria: While bacteria can cause lawn diseases (like brown patch), they do not grow in the organized, radial mycelial patterns required to form fairy rings. - Insects: Insects may cause patches of damage or 'brown patches' due to feeding, but they do not create the characteristic expanding circular growth pattern associated with fairy rings. - Nematodes: These are microscopic roundworms that typically cause stunted growth or root galling, not large-scale circular surface patterns.

Fertigation is the process of applying fertilizers through an irrigation system. The suitability of a fertilizer for fertigation depends primarily on its water solubility and its tendency to react with other ions to form precipitates that can clog emitters and drippers. 1. **Nitrogen fertilizers (Option a):** Most nitrogen sources used in fertigation (like Urea or Ammonium Nitrate) are highly water-soluble and move easily through irrigation systems, making them very suitable. 2. **Potassium fertilizers (Option c):** Potassium salts (like Potassium Nitrate or Potassium Sulfate) are generally soluble and compatible with most irrigation systems. 3. **Phosphorus fertilizers (Option b):** Phosphorus is the most problematic nutrient in fertigation. Many phosphorus sources (especially phosphates) have low solubility in certain pH ranges and a high tendency to react with Calcium (Ca) and Magnesium (Mg) present in the water to form insoluble precipitates (like Calcium Phosphate). These precipitates cause scaling and clogging of the drip emitters, making phosphorus fertilizers the least suitable among the three options unless specific acid-treated or highly soluble forms are used.

Bunchy top of banana is a devastating disease caused by the Banana Bunchy Top Virus (BBTV), which belongs to the genus Babuvirus. The disease is characterized by the stunted growth of leaves, which become narrow and stand erect, creating a 'bunched' appearance at the top of the plant. It is primarily transmitted by the banana aphid (Pentalonia nigronervosa). Why other options are incorrect: - a. Fungus: While fungi cause diseases like Fusarium wilt (Panama disease) in bananas, they do not cause Bunchy top. - b. Bacteria: Bacterial diseases in bananas include Bacterial Wilt (Ralstonia solanacearum), but not Bunchy top. - d. Physiological factor: Physiological disorders are caused by nutrient deficiencies or environmental stress, whereas Bunchy top is an infectious disease caused by a biological pathogen.

Garlic varieties are generally classified based on their vernalization requirements and day-length sensitivity for bulb formation. 1. **Agrifound Parvati**: This is a well-known 'Long Day' variety of garlic developed for specific climatic conditions where longer photoperiods are required to trigger the differentiation of the bulb. 2. **Yamuna Safed**: This is typically categorized as a 'Short Day' or 'Intermediate Day' variety, commonly grown in the plains of North India. 3. **G 282**: This is a high-yielding variety but is generally not classified as a primary long-day type in standard agricultural textbooks compared to the Agrifound series. 4. **Agrifound White**: While part of the Agrifound series, 'Parvati' is specifically highlighted in agricultural literature as the representative long-day type among the options provided. Therefore, Agrifound Parvati is the correct answer as it requires longer days to initiate bulb development.

In fruit physiology, fruits are categorized into two types based on their ripening patterns: climacteric and non-climacteric. 1. **Climacteric Fruits**: These fruits exhibit a burst of ethylene production and a sharp increase in respiration rate during ripening. They can be harvested while unripe and will continue to ripen off the plant. Examples include Mango (Option b), Banana (Option c), and Fig (Option d). 2. **Non-Climacteric Fruits**: These fruits do not show a significant increase in ethylene production or respiration during ripening. They must ripen on the parent plant to reach full quality and do not ripen further once harvested. Citrus fruits, such as the Orange (Option a), are classic examples of non-climacteric fruits. Therefore, among the given options, the Orange is the only non-climacteric fruit.

Arka Nikita is a high-yielding, determinate variety of Tomato developed by the Indian Institute of Horticultural Research (IIHR), Bengaluru. It is characterized by its resistance to leaf curl virus and high productivity. Analysis of other options: - Brinjal: Common 'Arka' varieties include Arka Keshav and Arka Navneet. - Onion: Common varieties include Agrifound or various regional hybrids, but Arka Nikita is not one of them. - Okra: Common varieties include Arka Anamika.

Little leaf of mango is a classic physiological disorder caused by the deficiency of Zinc (Zn). Zinc is an essential micronutrient required for the synthesis of tryptophan, which is a precursor to the plant growth hormone Auxin (specifically Indole-3-acetic acid or IAA). When Zinc is deficient, auxin levels drop, leading to stunted shoot growth and the characteristic development of abnormally small, narrow leaves (little leaves) and shortened internodes, giving the plant a rosette or bunchy appearance. Why other options are incorrect: - Iron (Fe) deficiency typically manifests as interveinal chlorosis (yellowing of young leaves while veins remain green). - Calcium (Ca) deficiency usually results in the death of growing tips (meristems) or blossom end rot in fruits. - Molybdenum (Mo) toxicity is rare in mangoes; Mo deficiency usually affects nitrogen fixation or causes 'whiptail' in other crops like cauliflower.

In a honey bee colony, there are three castes: the Queen, the Drones, and the Workers. 1. **Workers (Option b):** These are sterile females. They perform all the colony's maintenance tasks, including foraging for nectar and pollen, cleaning the hive, nursing the larvae, and guarding the entrance. Although they are female, their reproductive organs are underdeveloped, meaning they cannot mate or lay fertilized eggs. 2. **Drones (Option a):** These are the males of the colony. Their sole purpose is to mate with a virgin queen. They are haploid (developed from unfertilized eggs). 3. **Queen:** She is the only fertile female in the colony, responsible for laying all the eggs. Since workers are biologically female (developed from fertilized eggs), option 'b' is the correct answer. Option 'c' (Hermaphrodite) is incorrect as bees have distinct sexes, and option 'd' is incorrect because the worker caste consists exclusively of females.

Parthenocarpy is the development of fruit without the fertilization of ovules, resulting in seedless fruits. In the case of the commercial Banana (Musa spp.), the fruit develops without pollination or fertilization, making it a classic example of natural parthenocarpy. Analysis of other options: - Guava: Typically produces seeds through normal fertilization, although some specific cultivars may be seedless, it is not a characteristic feature of the species. - Litchi: Produces a single large seed; it is not parthenocarpic. - Citrus: While some citrus fruits can exhibit stenospermocarpy (where seeds abort), the general characteristic of the genus is not parthenocarpy in the same fundamental way as the commercial banana.

Tomato Leaf Curl Virus (ToLCV) is caused by a begomovirus (genus Begomovirus, family Geminiviridae). These viruses are specifically transmitted by the whitefly species Bemisia tabaci in a persistent, circulative manner. Reasoning for other options: - a. Thrips: These are primary vectors for Tospoviruses (e.g., Tomato Spotted Wilt Virus), not leaf curl viruses. - c. Aphids: These transmit a wide variety of viruses (e.g., Potato Virus Y), but they are not the vectors for ToLCV. - d. Fruit fly: These are pests that cause direct damage to the fruit through larval feeding and are not known to be vectors for plant viruses like ToLCV.

Oyster mushrooms (Pleurotus species) are saprophytic fungi, meaning they derive nutrients from decaying organic matter. They are particularly efficient at breaking down cellulose and lignin. 1. Why Straw is correct: Agricultural residues such as paddy straw, wheat straw, and corn stalks are the most common substrates for oyster mushroom cultivation because they provide the necessary carbon source (cellulose) and a porous structure that allows for aeration and mycelial growth. 2. Why Compost is incorrect: While compost is the primary substrate for Button mushrooms (Agaricus bisporus), oyster mushrooms do not require the complex composting process and grow better on raw, pasteurized lignocellulosic materials. 3. Why Sand is incorrect: Sand is inorganic and contains no nutrients (carbon or nitrogen) required for fungal growth. 4. Why Clay is incorrect: Clay is a dense mineral soil that lacks organic nutrients and prevents the necessary gas exchange (oxygen) required for the mycelium to breathe.

Polyembryony is the phenomenon where two or more embryos are present in a single seed. This can occur through several mechanisms: 1) The development of multiple zygotes from multiple fertilizations, 2) The development of embryos from synergids or antipodal cells (apomixis), or 3) The development of embryos directly from nucellar cells. - Citrus species (like lemon, orange) are the most classic examples of polyembryony, where nucellar cells frequently divide to form additional embryos alongside the zygotic embryo. - Jamun (Syzygium cumini) also exhibits polyembryony. - While some other fruits may show occasional anomalies, Citrus and Jamun are textbook examples of plants where this trait is characteristic and common. Therefore, option (b) is the most accurate and comprehensive answer.

Metaxia refers to a specific fungal pathogen or associated disease complex often linked to the Date Palm (Phoenix dactylifera). In the context of plant pathology and horticultural diseases, Metaxia species (specifically associated with certain root or stem rot complexes in specific regions) are documented in the study of Date Palm pathology. While other options like Papaya, Avocado, and Aonla have their own distinct sets of fungal and viral pathogens (e.g., Phytophthora in Avocado or Ringspot in Papaya), Metaxia is specifically associated with the Date palm in specialized plant pathology literature.

N-acetylcysteine (NAC) is the gold-standard antidote for acetaminophen (paracetamol) toxicity. Acetaminophen is metabolized in the liver; a small portion is converted into a highly reactive and toxic metabolite called NAPQI (N-acetyl-p-benzoquinone imine). Under normal conditions, NAPQI is neutralized by glutathione. In an overdose, glutathione stores are depleted, leading to NAPQI causing massive hepatic necrosis. N-acetylcysteine acts by replenishing glutathione stores and directly binding to NAPQI, thereby preventing liver damage. Regarding the other options: - Ivermectin toxicity is typically managed with supportive care (e.g., GABA receptor modulation or sedation). - Xylazine is an alpha-2 adrenergic agonist; its toxicity is managed with supportive care or specific alpha-2 antagonists like Yohimbine. - Warfarin toxicity (excessive anticoagulation) is treated with Vitamin K or Prothrombin Complex Concentrate (PCC).