ICAR JRF Plant Science Practice Series Memory Based 2024 (Module 1) (1 – 40 MCQ) 

 

Question 1

A polyploid organism in which the multiple sets of chromosomes are all derived from the same species:

1. Autopolyploid
2. Allopolyploid
3. Diploid
4. Tetraploid

Correct Answer: 1

Explanation:

• Autopolyploid– An organism with multiple sets of chromosomes all derived from the same species (e.g., triploid banana, tetraploid potato).
• Allopolyploid– Chromosome sets derived from different species (e.g., wheat, cotton).
• Diploid– Two sets of chromosomes.
• Tetraploid– Four sets (can be auto or allo).
• Therefore, the correct answer is Autopolyploid→ Option 1.

 

 

Question 2

What is the contribution of agriculture in Indian GDP during 2016-13? (Likely 2013-14)

1. 16%
2. 7%
3. 4%
4. 6%

Correct Answer: 2

Explanation:

• Agriculture’s contribution to Indian GDP during 2013-14was approximately 7% (as per the answer key).
• This share has been declining over the years due to the growth of the service and industrial sectors.
• Therefore, the correct answer is 7%→ Option 2.

 

 

Question 3

What should be the depth of water at the time of transplanting of paddy in field?

1. 10 cm
2. 2 cm
3. 5 cm
4. 5 cm

Correct Answer: 4

Explanation:

• At the time of transplanting paddy, a water depth of 2–5 cmis recommended. The answer key indicates 5 cm.
• Shallow water (2-5 cm) helps in easy establishment of seedlings, weed suppression, and prevents bird damage.
• 10 cm– Too deep; may cause seedling mortality.
• Therefore, the correct answer is 5 cm→ Option 4.

 

 

Question 4

The seed rate required for maize hybrid to sow one hectare of land is:

1. 20 Kg
2. 8 Kg
3. 25 Kg
4. 16 Kg

Correct Answer: 1

Explanation:

• The recommended seed rate for maize hybridis approximately 20 kg/ha (depending on spacing and seed size).
• 8 kg/ha– Too low for maize.
• 16 kg/ha, 25 kg/ha– Not standard.
• Therefore, the correct answer is 20 Kg→ Option 1.

 

 

Question 5

Which is the first important staple food crop of India?

1. Wheat
2. Maize
3. Sorghum
4. Rice

Correct Answer: 4

Explanation:

• Riceis the most important staple food crop of India, followed by wheat.
• India is the second-largest producer of rice in the world.
• Therefore, the correct answer is Rice→ Option 4.

 

 

Question 6

Largest producing state of chickpea in India is:

1. Haryana
2. Madhya Pradesh
3. Maharashtra
4. Karnataka

Correct Answer: 2

Explanation:

• Madhya Pradeshis the largest producer of chickpea (Bengal gram) in India, accounting for nearly 40-50% of total production.
• Maharashtra, Rajasthan, Karnataka– Other major producers but less than Madhya Pradesh.
• Therefore, the correct answer is Madhya Pradesh→ Option 2.

 

 

Question 7

Natural hybridization has taken place between the following two species of mango in Southeast Asia:

1. indicaand M. sylvatica
2. indicaand M. subessillifolia
3. indicaand M. kemanga
4. indicaand M. blommesteinii

Correct Answer: 1

Explanation:

• Natural hybridization between Mangifera indica(cultivated mango) and Mangifera sylvatica (wild species) has been reported in Southeast Asia.
• Other options are not known for natural hybridization with  indica.
• Therefore, the correct answer is  indicaand M. sylvatica → Option 1.

 

 

Question 8

Incompatibility reaction of pollen controlled by the genotype of the plant on which it produced:

1. Heteromorphic incompatibility
2. Sporophytic incompatibility
3. Gametophytic incompatibility
4. Tristyly

Correct Answer: 2

Explanation:

• Sporophytic incompatibility– The incompatibility reaction of pollen is determined by the genotype of the parent plant (sporophyte) , not by the pollen’s own genotype.
• Gametophytic incompatibility– Determined by the pollen’s own genotype (gametophyte).
• Heteromorphic incompatibility– Based on flower morphology (pin/thrum).
• Therefore, the correct answer is Sporophytic incompatibility→ Option 2.

 

 

Question 9

CGMS system is not utilised for hybrid seed production of:

1. Pearl millet
2. Sunflower
3. Rice
4. Maize

Correct Answer: 4

Explanation:

• CGMS (Cytoplasmic Genetic Male Sterility)is used for hybrid seed production in pearl millet, sunflower, rice, sorghum.
• Maize– Uses CMS (cytoplasmic male sterility) like T-cytoplasm, but CGMS is not the standard term; also, maize historically used detasseling.
• Therefore, the correct answer is Maize→ Option 4.

 

 

Question 10

A small chromosome fragment that lacks a centromere and is unable to orientate properly during cell division:

1. Metacentric
2. Acentric
3. Acellular
4. Telocentric

Correct Answer: 2

Explanation:

• Acentric– A chromosome or fragment that lacks a centromere. It cannot attach to spindle fibers and is often lost during cell division.
• Metacentric– Centromere in the middle.
• Telocentric– Centromere at the end.
• Acellular– Without cells.
• Therefore, the correct answer is Acentric→ Option 2.

 

 

Question 11

The phase in cell cycle in which the DNA content of the cell doubles and the chromosomes replicate is:

1. M phase
2. S phase
3. G₁ phase
4. G₂ phase

Correct Answer: 2

Explanation:

• S phase (Synthesis phase)– DNA replication occurs, doubling the DNA content from 2C to 4C.
• M phase– Mitosis (cell division).
• G₁ phase– Cell growth, protein synthesis.
• G₂ phase– Preparation for mitosis.
• Therefore, the correct answer is S phase→ Option 2.

 

 

Question 12

The point at which paired homologous chromosomes remain in contact as they begin to separate during the first prophase of meiosis, forming a cross shape is:

1. Cross linkage
2. Chiasma
3. Cross over value
4. Crossing over

Correct Answer: 2

Explanation:

• Chiasma (plural: chiasmata)– The point of contact between non-sister chromatids of homologous chromosomes where crossing over has occurred. They appear as cross-shaped structures during diplotene/diakinesis.
• Crossing over– The process of exchange.
• Cross over value– Frequency of recombination.
• Therefore, the correct answer is Chiasma→ Option 2.

 

 

Question 13

In plant cells, the intercellular transport of solutes through plasmodesmata is known as:

1. Active transport
2. Membrane transport
3. Symplastic transport
4. Osmosis

Correct Answer: 3

Explanation:

• Symplastic transport– Movement of solutes through the cytoplasm and plasmodesmata connecting adjacent plant cells.
• Apoplastic transport– Movement through cell walls and intercellular spaces.
• Active transport, membrane transport, osmosis– Not specific to plasmodesmata.
• Therefore, the correct answer is Symplastic transport→ Option 3.

 

 

Question 14

Colourless, odourless, non-flammable atmospheric gas used in photosynthesis is:

1. Carbon dioxide
2. Carbon monoxide
3. Oxygen
4. Methane

Correct Answer: 1

Explanation:

• Carbon dioxide (CO₂)– Colourless, odourless, non-flammable, and used by plants in photosynthesis to produce glucose.
• Oxygen– Produced in photosynthesis, not used.
• Carbon monoxide, methane– Not used in photosynthesis.
• Therefore, the correct answer is Carbon dioxide→ Option 1.

 

 

Question 15

The process by which green plants convert carbon dioxide and water into sugar and oxygen using sunlight as energy is called:

1. Photosynthesis
2. Photosensitization
3. Photosynthesis (duplicate)
4. Transpiration

Correct Answer: 1

Explanation:

• Photosynthesis– The process by which green plants convert CO₂ and H₂O into glucose and O₂ using sunlight energy captured by chlorophyll.
• Transpiration– Loss of water vapor.
• Therefore, the correct answer is Photosynthesis→ Option 1.

 

 

Question 16

The C₄ metabolic pathway in plants have:

1. High photorespiration
2. Low photorespiration
3. No photorespiration
4. Moderate photorespiration

Correct Answer: 2

Explanation:

• C₄ plantshave a mechanism to concentrate CO₂ in bundle sheath cells, which minimizes photorespiration (very low levels).
• C₃ plants– High photorespiration.
• Therefore, the correct answer is Low photorespiration→ Option 2.

 

 

Question 17

In leaves, below the epidermis, the top layers of photosynthetic cells are called:

1. Tapetal cells
2. Spongy mesophyll cells
3. Palisade cells
4. Guard cells

Correct Answer: 3

Explanation:

• Palisade cells– Elongated, columnar cells just below the upper epidermis of leaves. They contain many chloroplasts and are the primary site of photosynthesis.
• Spongy mesophyll– Below palisade layer, irregular cells with air spaces.
• Tapetal cells– In anthers.
• Guard cells– Surround stomata.
• Therefore, the correct answer is Palisade cells→ Option 3.

 

 

Question 18

The information carried by an organism’s DNA which determines the synthesis of proteins by cells and which is passed on when the cell divides:

1. Genetic material
2. Genetic modification
3. Amino acid
4. Genetic code

Correct Answer: 4

Explanation:

• Genetic code– The set of rules by which information encoded in DNA (or RNA) is translated into proteins (sequences of amino acids). It is passed on during cell division.
• Genetic material– DNA itself.
• Genetic modification– Artificial alteration.
• Therefore, the correct answer is Genetic code→ Option 4.

 

 

Question 19

The glyoxysomes and peroxisomes present in plant cells are called:

1. Chromatophores
2. Stromal lamella
3. Microbodies
4. Thylakoids

Correct Answer: 3

Explanation:

• Microbodies– A class of membrane-bound organelles that include glyoxysomes (in oilseeds, glyoxylate cycle) and peroxisomes (photorespiration).
• Chromatophores– Pigment-containing structures in bacteria.
• Stromal lamella, thylakoids– Chloroplast structures.
• Therefore, the correct answer is Microbodies→ Option 3.

 

 

Question 20

Under light microscopy plant cells are measured in micrometer, where one micrometer is equal to:

1. 10⁻⁵ m
2. 10⁻³ m
3. 10⁻⁶ m
4. 10⁻² m

Correct Answer: 3

Explanation:

• 1 micrometer (µm)= 10⁻⁶ meters (one-millionth of a meter).
• 10⁻³ m– 1 millimeter (mm).
• 10⁻² m– 1 centimeter (cm).
• Therefore, the correct answer is 10⁻⁶ m→ Option 3.

 

 

Question 21

During enzyme activity, many enzymes require non-protein helpers for their catalytic activity and these adjuncts are called:

1. Competitive inhibitors
2. Enhancers
3. Competitive enhancers
4. Co-enzymes

Correct Answer: 4

Explanation:

• Co-enzymes– Non-protein organic molecules (e.g., vitamins, NAD, FAD) that assist enzymes in catalysis.
• Cofactors– Include co-enzymes and metal ions.
• Inhibitors– Reduce enzyme activity.
• Therefore, the correct answer is Co-enzymes→ Option 4.

 

 

Question 22

The fibre yielding Corchorus sp. which contains a bitter glycoside Corchorin:

1. Corchorus olitorius
2. Corchorus capsularis
3. Corchorus cunninghamii
4. Corchorus erodioides

Correct Answer: 1

Explanation:

• Corchorus olitorius(Tossa jute) contains a bitter glycoside called corchorin.
• Corchorus capsularis(White jute) does not contain this bitter principle.
• Therefore, the correct answer is Corchorus olitorius→ Option 1.

 

 

Question 23

Mascotting is practised in which crop for making controlled cross pollination:

1. Beta vulgaris
2. Panicum maximum
3. Heteropogon contortus
4. Saccharum officinarum

Correct Answer: 4

Explanation:

• Mascotting– A technique used in sugarcane (Saccharum officinarum) breeding to facilitate controlled cross-pollination by collecting and storing pollen from male parents.
• Therefore, the correct answer is Saccharum officinarum→ Option 4.

 

 

Question 24

Which of the following crop species possesses a cluster of hairs at the tip of the anthers?

1. Eleusine coracana
2. Pennisetum glaucum
3. Setaria italica
4. Panicum sumatrense

Correct Answer: 2

Explanation:

• Pennisetum glaucum(pearl millet / bajra) has anthers with a cluster of hairs at the tip.
• This is a characteristic feature used in identification.
• Therefore, the correct answer is Pennisetum glaucum→ Option 2.

 

 

Question 25

In a nucleotide, polymers containing 50 or fewer nucleotides are generally referred as:

1. mRNA
2. Polynucleotide
3. Oligonucleotide
4. siRNA

Correct Answer: 3

Explanation:

• Oligonucleotide– Short nucleic acid polymers containing 50 or fewer nucleotides.
• Polynucleotide– Longer chains (more than 50 nucleotides).
• mRNA, siRNA– Types of RNA, not defined by length.
• Therefore, the correct answer is Oligonucleotide→ Option 3.

 

 

Question 26

Among the conceptual classes of alleles, which two classes are more relevant while formulating core collection sampling strategies?

1. Common and widespread
2. Rare and localized
3. Very rare and restricted
4. Rare and widespread

Correct Answer: 2

Explanation:

• When formulating core collection sampling strategies, rare and localized allelesare most relevant to capture maximum genetic diversity.
• Common and widespread alleles are already well-represented.
• Therefore, the correct answer is Rare and localized→ Option 2.

 

 

Question 27

Watson and Crick constructed the DNA model, where the 5′, 3′ phosphodiester bonds run in which direction?

1. Parallel
2. Alternate
3. Antiparallel
4. One

Correct Answer: 3

Explanation:

• In the Watson-Crick DNA model, the two strands run in antiparalleldirections (one 5’→3′, the other 3’→5′).
• This allows complementary base pairing.
• Therefore, the correct answer is Antiparallel→ Option 3.

 

 

Question 28

The cell organelle from where chemical changes associated with respiration take place:

1. Golgi body
2. Mitochondria
3. Plastids
4. Chloroplasts

Correct Answer: 2

Explanation:

• Mitochondria– The site of cellular respiration (Krebs cycle and oxidative phosphorylation), where chemical changes produce ATP.
• Chloroplasts– Photosynthesis.
• Golgi body– Protein packaging.
• Therefore, the correct answer is Mitochondria→ Option 2.

 

 

Question 29

The technology that prevents farmers from harvesting a crop by saving seed from the current year’s crop to plant the next season’s crop is termed as:

1. Hybrid technology
2. Transgenic technology
3. Apomixis
4. Terminator technology

Correct Answer: 4

Explanation:

• Terminator technology(Genetic Use Restriction Technology – GURT) – Produces sterile seeds, preventing farmers from saving seeds for replanting.
• Apomixis– Produces clonal seeds (fixes heterosis).
• Hybrid technology– Produces high-yielding seeds but must be repurchased.
• Therefore, the correct answer is Terminator technology→ Option 4.

 

 

Question 30

The cytological event when unreduced megaspore mother cell produces the embryo sac following mitosis instead of meiosis is called:

1. Diplospory
2. Apospory
3. Adventitious embryo
4. Adventitious apomixis

Correct Answer: 1

Explanation:

• Diplospory– A type of apomixis where the megaspore mother cell (MMC) undergoes mitosis (instead of meiosis) to produce an unreduced embryo sac (diploid).
• Apospory– Embryo sac develops from a somatic cell (nucellus).
• Adventitious embryony– Embryos from nucellus or integuments.
• Therefore, the correct answer is Diplospory→ Option 1.

 

 

Question 30

The cytological event when unreduced megaspore mother cell produces the embryo sac following mitosis instead of meiosis is called:

1. Diplospory
2. Apospory
3. Adventitious embryo
4. Adventitious apomixis

Correct Answer: 1

Explanation:

• Diplospory– A type of apomixis where the megaspore mother cell (MMC) undergoes mitosis (instead of meiosis) to produce an unreduced embryo sac (diploid).
• Apospory– Embryo sac develops from a somatic cell (nucellus).
• Adventitious embryony– Embryos from nucellus or integuments.
• Therefore, the correct answer is Diplospory→ Option 1.

 

 

Question 31

In plant breeding, while selecting for a trait generation after generation, if the mean would change towards the direction of selection, then the trait is a:

1. Monogenic trait
2. Bigenic trait
3. Polygenic trait
4. Epistatic trait

Correct Answer: 3

Explanation:

• Polygenic trait– Controlled by many genes (quantitative). When selection is applied generation after generation, the mean shifts towards the direction of selection due to additive gene action.
• Monogenic trait– Controlled by one gene; selection gives discrete classes, not a gradual shift in mean.
• Epistatic trait– Involves gene interaction, not necessarily a gradual mean shift.
• Therefore, the correct answer is Polygenic trait→ Option 3.

 

 

Question 32

While transferring a homozygous dominant gene from parent B to A, which has homozygous recessive gene; which generation will have half the population possessing the dominant gene?

1. F₁
2. F₂
3. BC₁
4. BC₂

Correct Answer: 3

Explanation:

• BC₁ (First backcross generation)– Cross between F₁ (Aa) and the recurrent parent (aa). The progeny will be 1:1 (Aa : aa). Therefore, half the population will possess the dominant gene (Aa) .
• F₁– All Aa (100% dominant).
• F₂– 3:1 ratio (75% dominant).
• BC₂– 75% dominant? Not half.
• Therefore, the correct answer is BC₁→ Option 3.

 

 

Question 33

Among the inflorescence of food legumes, which of the following species possesses solitary flowers?

1. Cajanus cajan
2. Cicer arietinum
3. Vigna radiata
4. Lablab purpureus

Correct Answer: 2

Explanation:

• Cicer arietinum(chickpea) – Inflorescence is a solitary flower (one flower per axil).
• Cajanus cajan(pigeon pea) – Racemose inflorescence with multiple flowers.
• Vigna radiata(green gram) – Racemose with clusters.
• Lablab purpureus(hyacinth bean) – Racemose.
• Therefore, the correct answer is Cicer arietinum→ Option 2.

 

 

Question 34

To circumvent a major barrier to interspecific crossing, breeders use the following technique:

1. Chromosome doubling
2. Heterosis breeding
3. Shuttle breeding
4. Bulbosum technique

Correct Answer: 4

Explanation:

• Bulbosum technique– Used to overcome crossing barriers in interspecific hybridization, especially in barley (Hordeum). It involves using Hordeum bulbosum as a pollinator to induce haploid production.
• Chromosome doubling– Used after hybridization to restore fertility.
• Shuttle breeding– Alternating between two locations to accelerate breeding.
• Therefore, the correct answer is Bulbosum technique→ Option 4.

 

 

Question 35

The sum of the external conditions that affect growth and development of a plant:

1. Ectotype
2. Environment
3. Habitat
4. Phenotype

Correct Answer: 2

Explanation:

• Environment– The sum total of all external conditions (light, temperature, water, soil, etc.) that affect the growth and development of a plant.
• Ectotype– A population adapted to local conditions.
• Habitat– The specific place where a plant lives.
• Phenotype– The observable expression of genotype + environment.
• Therefore, the correct answer is Environment→ Option 2.

 

 

Question 36

Male sterility controlled by the interaction of a genetic factor present in the cytoplasm and nuclear gene:

1. CMS
2. CGMS
3. GMS
4. EGMS

Correct Answer: 2

Explanation:

• CGMS (Cytoplasmic Genetic Male Sterility)– Male sterility controlled by the interaction of cytoplasmic factors (mitochondrial genes) and nuclear genes (restorer genes) .
• CMS– Cytoplasmic male sterility (only cytoplasmic, without nuclear restorer).
• GMS– Genetic male sterility (nuclear only).
• EGMS– Environment-sensitive genic male sterility.
• Therefore, the correct answer is CGMS→ Option 2.

 

 

Question 37

The mechanism which promotes self pollination in crop plants is:

1. Monoecy
2. Dichogamy
3. Chasmogamy
4. Heterostyly

Correct Answer: 3

Explanation:

• Chasmogamy– Flowers open, allowing pollination. In self-pollinated crops, chasmogamy still occurs but pollination happens before flower opening (cleistogamy) or within the same flower. However, among the options, chasmogamy is associated with self-pollination in many crops.
• Monoecy– Male and female flowers on same plant (promotes cross-pollination).
• Dichogamy– Male and female parts mature at different times (promotes cross-pollination).
• Heterostyly– Different style lengths (promotes cross-pollination).
• Therefore, the correct answer is Chasmogamy→ Option 3.

 

 

Question 38

Reclamation of sodic soils is undertaken by application of:

1. Gypsum
2. Zinc sulphate
3. Green manure
4. Farmyard manure

Correct Answer: 1

Explanation:

• Gypsum (CaSO₄·2H₂O)– Used for reclamation of sodic (alkali) soils. Calcium in gypsum replaces sodium on the exchange complex, and sodium is leached out as sodium sulfate.
• Zinc sulphate– For zinc deficiency.
• Green manure, FYM– Improve soil health but not effective for sodic soil reclamation.
• Therefore, the correct answer is Gypsum→ Option 1.

 

 

Question 39

According to N.I. Vavilov, maximum diversity for Citrus sp. was present in the regions of:

1. China centre
2. Mediterranean centre
3. Hindustan centre
4. Asia minor centre

Correct Answer: 1

Explanation:

• According to Vavilov’s Centers of Origin, maximum diversity for Citrusspecies is found in the Chinese centre (Southeast Asia, including China and Indochina).
• Mediterranean centre– Origin of wheat, barley, chickpea.
• Hindustan centre– Origin of rice, pigeon pea, eggplant.
• Therefore, the correct answer is China centre→ Option 1.

 

 

Question 40

The wild progenitor of Oryza sativa:

1. rufipogon
2. nigistaminala(likely O. longistaminata)
3. barthii
4. nivara

Correct Answer: 4

Explanation:

• Oryza nivarais considered the wild progenitor of cultivated rice (Oryza sativa). It is a wild annual rice species from Asia.
• rufipogon– Also a wild relative, but O. nivara is often cited as the direct progenitor.
• barthii– Wild rice from Africa.
• Therefore, the correct answer is  nivara→ Option 4.