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

 

 

Question 1

Which among the following is not a variety of mango?

1. Alphonso
2. Amrapalli
3. Chausa
4. Arka Jyothi

Correct Answer: 4

Explanation:

• Alphonso, Amrapalli, and Chausaare all well-known mango varieties.
• Arka Jyothiis a variety of brinjal (eggplant) developed by IIHR, Bengaluru, not a mango variety.
• Therefore, the correct answer is Arka Jyothi→ Option 4.

 

 

Question 2

The most important organelle for synthesis of fatty acid is:

1. Mitochondria
2. Chloroplast
3. Nucleus
4. All the above

Correct Answer: 2

Explanation:

• Fatty acid synthesisoccurs primarily in the chloroplast in plants (in the stroma).
• Acetyl-CoA is carboxylated to malonyl-CoA by acetyl-CoA carboxylase, and fatty acid synthase (FAS) complex assembles the fatty acid chain.
• Mitochondria– Site of fatty acid oxidation (β-oxidation), not synthesis.
• Nucleus– Contains DNA but not involved in fatty acid synthesis.
• Therefore, the correct answer is Chloroplast→ Option 2.

 

 

Question 3

Cotton leaf curl virus is transmitted by:

1. Mites
2. Aphids
3. Whitefly
4. Leaf hopper

Correct Answer: 3

Explanation:

• Cotton leaf curl virus (CLCuV)is a begomovirus (ssDNA, family Geminiviridae) transmitted by the whitefly, Bemisia tabaci (persistent circulative transmission).
• Mites– Transmit wheat streak mosaic virus, etc.
• Aphids– Transmit potyviruses, etc.
• Leaf hopper– Transmit rice tungro, etc.
• Therefore, the correct answer is Whitefly→ Option 3.

 

 

Question 4

Phytoplasma are transmitted by:

1. Leaf hopper
2. Tree hopper
3. Mites
4. Plant hopper

Correct Answer: 1

Explanation:

• Phytoplasmas(wall-less bacteria, Mollicutes) are transmitted primarily by leafhoppers (Cicadellidae) and also by planthoppers and psyllids.
• Tree hoppers– Less common vectors.
• Mites– Not vectors of phytoplasma.
• Plant hopper– Also transmit phytoplasma but leafhopper is the primary answer.
• Therefore, the correct answer is Leaf hopper→ Option 1.

 

 

Question 5

Which among the following is not a systemic fungicide?

1. Captan
2. Bavistin
3. Calixin
4. Vitavax

Correct Answer: 1

Explanation:

• Captan– A contact (non-systemic) fungicide (phthalimide group). It acts on the plant surface and is not absorbed.
• Bavistin (Carbendazim)– Systemic benzimidazole fungicide.
• Calixin (Tridemorph)– Systemic morpholine fungicide.
• Vitavax (Carboxin)– Systemic oxathiin fungicide.
• Therefore, the correct answer is Captan→ Option 1.

 

 

Question 6

One molecule of glucose produced how many ATP from Krebs cycle molecule?

1. 16
2. 30
3. 18
4. 36

Correct Answer: 2

Explanation:

• The Krebs cycle (TCA cycle) per molecule of glucose (2 turns) produces:
  • 2 ATP(substrate-level phosphorylation)
  • 6 NADH(each yields ~2.5 ATP) → ~15 ATP
  • 2 FADH₂(each yields ~1.5 ATP) → ~3 ATP
  • Total from Krebs cycle = 2 + 15 + 3 = ~20 ATP(not 30)
• However, if the question asks for total ATP from one glucose molecule including glycolysis, Krebs cycle, and oxidative phosphorylation, the total is ~30-32 ATP.
• The answer key indicates 30→ Option 2 (likely referring to total ATP yield).

 

 

Question 7

The arrangement of soil particles is known as:

1. Soil texture
2. Soil structure
3. Soil aggregation
4. All the above

Correct Answer: 2

Explanation:

• Soil structure– The arrangement of soil particles (sand, silt, clay) into aggregates or peds.
• Soil texture– The relative proportion of sand, silt, and clay particles (not arrangement).
• Soil aggregation– The process of forming aggregates (related to structure).
• Therefore, the correct answer is Soil structure→ Option 2.

 

 

Question 8

The most practicable antitranspirant only in greenhouse condition:

1. ABA
2. CO₂
3. Silicone wax
4. Plastic transpirant

Correct Answer: 2

Explanation:

• CO₂– Elevated CO₂ concentration causes stomatal closure and reduces transpiration. It is used in greenhouses but is not practical in open fields.
• ABA– A plant hormone that induces stomatal closure, but expensive for field use.
• Silicone wax, plastic transpirant– Film-forming antitranspirants, can be used in fields.
• Therefore, the correct answer is CO₂→ Option 2.

 

 

Question 9

The character not studied by Mendel is:

1. Seed coat colour
2. Cotyledon colour
3. Flower colour
4. Flower position

Correct Answer: 3

Explanation:

• Mendel studied 7 charactersin pea (Pisum sativum):
  • Seed shape (round/wrinkled)
  • Seed colour (yellow/green)
  • Flower colour (purple/white) – Yes, he studied flower colour
  • Pod shape (inflated/constricted)
  • Pod colour (green/yellow)
  • Flower position (axial/terminal)
  • Stem height (tall/dwarf)
• Cotyledon colourand seed coat colour are also studied.
• All options were studied. The question may have a trick, but as per the answer key, Flower colouris marked as the answer? The key says option 3. Possibly the question means “not studied” – but Mendel did study flower colour. There may be an error. Given the key, Option 3 is correct as per the answer key.

 

 

Question 10

ABA regulates:

1. Photosynthesis
2. Dormancy
3. Imbibition
4. All the above

Correct Answer: 2

Explanation:

• Abscisic acid (ABA)– A plant hormone that regulates dormancy (seed and bud dormancy), stomatal closure, and stress responses.
• Photosynthesis– Not directly regulated by ABA (ABA inhibits stomatal opening, indirectly affecting photosynthesis).
• Imbibition– Water uptake by seeds; ABA inhibits germination but not directly regulates imbibition.
• Therefore, the correct answer is Dormancy→ Option 2.

 

 

Question 11

Coffee rust first reported in India in:

1. 1856
2. 1870
3. 1940
4. 1945

Correct Answer: 2

Explanation:

• Coffee rust(caused by Hemileia vastatrix) was first reported in Sri Lanka in 1869 and in India in 1870.
• It caused severe losses to coffee plantations in the late 19th century.
• Therefore, the correct answer is 1870→ Option 2.

 

 

Question 12

The interaction between two alleles of the same gene is:

1. Dominance
2. Epistasis
3. Pleiotropy
4. Recessive

Correct Answer: 1

Explanation:

• Dominance– Interaction between two alleles of the same gene (e.g., Aa). One allele (dominant) masks the expression of the other (recessive).
• Epistasis– Interaction between different genes (non-allelic).
• Pleiotropy– A single gene affects multiple traits.
• Recessive– An allele whose effect is masked by a dominant allele.
• Therefore, the correct answer is Dominance→ Option 1.

 

 

Question 13

1. junceais a cross between:
2. nigra× B. campestris
3. campestris× B. oleracea
4. nigra× B. oleracea
5. campestris× B. carinata

Correct Answer: 1

Explanation:

• Brassica juncea(Indian mustard) is an allotetraploid (AABB, 2n=36) derived from hybridization between  nigra (BB, 2n=16) and B. campestris (AA, 2n=20).
• Triangle of Udescribes the genomic relationships among Brassica
• campestris × B. oleracea– Gives B. napus.
• nigra × B. oleracea– Gives B. carinata.
• Therefore, the correct answer is  nigra × B. campestris→ Option 1.

 

 

Question 14

Block system is used in the hybrid production of:

1. Cotton
2. Sunflower
3. Both a and b
4. Soybean

Correct Answer: 1

Explanation:

• Block system– A method of hybrid seed production where male and female parents are planted in separate blocks to facilitate crossing and rouging.
• It is commonly used in cottonhybrid production.
• Sunflower– Uses row interplanting or other systems.
• Therefore, the correct answer is Cotton→ Option 1.

 

 

Question 15

Crop with 1000 m isolation distance in certified class is:

1. Cauliflower
2. Cucumber
3. Rapeseed
4. Arabidopsis

Correct Answer: 1

Explanation:

• Isolation distancefor cauliflower (cross-pollinated vegetable) for certified seed production is 1000 meters as per Indian Minimum Seed Certification Standards.
• Cucumber, rapeseed, Arabidopsis– Have lower isolation distances.
• Therefore, the correct answer is Cauliflower→ Option 1.

 

 

Question 16

MNREGA was started in:

1. 2009
2. 2006
3. 2007
4. 2008

Correct Answer: 1

Explanation:

• MNREGA (Mahatma Gandhi National Rural Employment Guarantee Act)was enacted in 2005 and implemented in 2006 (not 2009). However, the answer key shows 2009.
• Possibly the question refers to a different scheme or a typo. Given the key, 2009is the answer.

 

 

Question 17

Community development programme started in:

1. 1952
2. 1953
3. 1954
4. 1955

Correct Answer: 1

Explanation:

• The Community Development Programme (CDP)in India was launched on October 2, 1952.
• It aimed at overall development of rural areas through a participatory approach.
• Therefore, the correct answer is 1952→ Option 1.

 

 

Question 18

Isozyme is a:

1. Recessive
2. Dominant
3. Co-dominant
4. Over dominant

Correct Answer: 3

Explanation:

• Isozymes (isoenzymes)– Multiple forms of the same enzyme that differ in amino acid sequence but catalyze the same reaction.
• In genetic marker terms, isozyme markers are co-dominant(both alleles are expressed and can be detected).
• Therefore, the correct answer is Co-dominant→ Option 3.

 

 

Question 19

Minimum error degree in a chi square test:

1. 12
2. 15
3. 20
4. 22

Correct Answer: 1

Explanation:

• In a chi-square (χ²) test, the degrees of freedom (df) depend on the number of classes.
• The question likely refers to a specific experimental setup (e.g., 3 classes → df = 2, 4 classes → df = 3). The number 12may refer to a specific case.
• Given the answer key, the correct answer is 12→ Option 1.

 

 

Question 20

Optimum temperature for soil microorganism:

1. 25-30°C
2. 30-32°C
3. 30-36°C
4. 18-20°C

Correct Answer: 1

Explanation:

• The optimum temperaturefor most soil microorganisms (bacteria, fungi, actinomycetes) is 25-30°C (mesophilic range).
• 30-36°C– Some thermophiles, but not the general optimum.
• 18-20°C– Too low for optimal microbial activity.
• Therefore, the correct answer is 25-30°C→ Option 1.

 

 

Question 21

End product of T₂ test is:

1. Chloride
2. Formazon
3. Red colour
4. Both a and b

Correct Answer: 2

Explanation:

• T₂ testrefers to the Tetrazolium test (TZ test) using 2,3,5-triphenyl tetrazolium chloride.
• Living cells with active dehydrogenaseenzymes reduce the colorless tetrazolium salt to a red, stable, insoluble compound called formazan.
• The end product is formazan(red colour), but the direct chemical end product is formazan.
• Therefore, the correct answer is Formazon→ Option 2.

 

 

Question 22

Genetic purity in field is controlled through:

1. Seed testing
2. Seed sampling
3. Grow out test
4. Rouging

Correct Answer: 4

Explanation:

• Rouging– The removal of off-type plants (unwanted variants) from the seed production field before they contaminate the seed lot. It is the primary method to maintain genetic purity in the field.
• Seed testing– Done in the laboratory (not in the field).
• Seed sampling– For collecting samples for testing.
• Grow out test– Done in the field after harvest to check genetic purity (not during crop growth).
• Therefore, the correct answer is Rouging→ Option 4.

 

 

Question 23

Maximum nitrogen content is present in:

1. Night soil
2. Poultry manure
3. Compost
4. Groundnut

Correct Answer: 4

Explanation:

• Groundnut (peanut)cake (oil cake) has very high nitrogen content (about 7-8% N), which is higher than most organic manures.
• Poultry manure– About 2-4% N.
• Night soil– About 1-2% N.
• Compost– About 0.5-1.5% N.
• Therefore, the correct answer is Groundnut→ Option 4.

 

 

Question 24

RNA is not involved in:

1. Heredity
2. Protein synthesis
3. Chromosome
4. Enzyme activity

Correct Answer: 3

Explanation:

• RNA– Involved in heredity (in some viruses), protein synthesis (mRNA, tRNA, rRNA), and enzyme activity (ribozymes).
• Chromosome– Composed of DNA and proteins (histones) , not RNA. RNA is not a structural component of chromosomes (except in some viral systems).
• Therefore, the correct answer is Chromosome→ Option 3.

 

 

Question 25

Lab to land programme was initiated in:

1. 1979
2. 1980
3. 1981
4. 1982

Correct Answer: 1

Explanation:

• The Lab to Land Programmewas initiated by the Indian Council of Agricultural Research (ICAR) in 1979 to transfer technology from research laboratories to farmers’ fields.
• Therefore, the correct answer is 1979→ Option 1.

 

 

Question 26

First DG of ICAR:

1. P. Pal
2. Ayyappan
3. B. Mundkur
4. S. Swaminathan

Correct Answer: 1

Explanation:

• B.P. Palwas the first Director General of ICAR (Indian Council of Agricultural Research) from 1965 to 1972.
• Ayyappan– Former DG of ICAR (later).
• B. Mundkur– Plant pathologist, not DG.
• S. Swaminathan– Second DG of ICAR.
• Therefore, the correct answer is P. Pal→ Option 1.

 

 

Question 27

Crop which takes nitrogen in ammoniacal form is:

1. Rice
2. Cotton
3. Potato
4. All the above

Correct Answer: 1

Explanation:

• Rice– Under waterlogged conditions, rice preferentially takes up ammonium (NH₄⁺) form of nitrogen because nitrification is inhibited in flooded soils.
• Cotton, potato– Prefer nitrate (NO₃⁻) form under aerobic conditions.
• Therefore, the correct answer is Rice→ Option 1.

 

 

Question 28

cry gene is obtained from:

1. subtilis
2. amylovora
3. thuringiensis
4. All the above

Correct Answer: 3

Explanation:

• The cry(crystal) genes encoding insecticidal crystal proteins (Cry toxins) are obtained from Bacillus thuringiensis (Bt).
• These genes are used in the development of Bt-transgenic crops (e.g., Bt cotton, Bt brinjal).
• subtilis– Does not produce Cry toxins.
• amylovora– Causes fire blight; does not produce Cry toxins.
• Therefore, the correct answer is  thuringiensis→ Option 3.

 

 

Question 29

C₂ cycle takes place in:

1. Chloroplast
2. Peroxisome
3. Mitochondria
4. All the above

Correct Answer: 4

Explanation:

• C₂ cycle (photorespiration)– Occurs in three organelles:
  • Chloroplast– Oxygenation of RuBP by Rubisco produces phosphoglycolate.
  • Peroxisome– Conversion of phosphoglycolate to glycine.
  • Mitochondria– Conversion of glycine to serine with release of CO₂.
• Therefore, the correct answer is All the above→ Option 4.

 

 

Question 30

Hormone involved in cell cycle:

1. Auxin
2. Cytokinin
3. BR
4. None of the above

Correct Answer: 2

Explanation:

• Cytokinins– Plant hormones that promote cell division (cytokinesis) and are involved in cell cycle regulation.
• Auxin– Promotes cell elongation, not directly cell division.
• BR (Brassinosteroids)– Promote cell elongation and division but cytokinin is the primary hormone associated with cell cycle.
• Therefore, the correct answer is Cytokinin→ Option 2.

 

 

Question 31

Under water stress condition which amino acid gets accumulated:

1. Proline
2. Methionine
3. Cystine
4. All the above

Correct Answer: 1

Explanation:

• Proline– A compatible osmolyte that accumulates in plants under water stress, salt stress, and other abiotic stresses. It helps in osmotic adjustment and protects cellular structures.
• Methionine, cystine– Not primarily accumulated under water stress.
• Therefore, the correct answer is Proline→ Option 1.

 

 

Question 32

National farmers day is observed on:

1. 23rd November
2. 23rd December
3. 23rd January
4. 23rd February

Correct Answer: 2

Explanation:

• National Farmers’ Day (Kisan Diwas)is observed on 23rd December in India, the birth anniversary of former Prime Minister Chaudhary Charan Singh.
• Therefore, the correct answer is 23rd December→ Option 2.

 

 

Question 33

Mycorrhiza helps in the uptake of:

1. K
2. N
3. S
4. P

Correct Answer: 4

Explanation:

• Mycorrhizae(VAM fungi) form symbiotic associations with plant roots and primarily enhance the uptake of phosphorus (P) , especially in phosphorus-deficient soils.
• They also help in uptake of other nutrients (Zn, Cu), but P is the most significant.
• Therefore, the correct answer is P→ Option 4.

 

 

Question 34

Green manure supplies:

1. Organic matter
2. Nitrogen
3. Both a and b
4. None of these

Correct Answer: 3

Explanation:

• Green manure– Growing and incorporating green plant biomass (e.g., Sesbania, Crotalaria, Sunhemp) into the soil.
• It supplies:
  • Organic matter(improves soil structure, water holding capacity)
  • Nitrogen(leguminous green manures fix atmospheric N₂)
• Therefore, the correct answer is Both a and b→ Option 3.

 

 

Question 35

Botanical name of pineapple fruit:

1. Syconus
2. Pome
3. Sorosis
4. None of these

Correct Answer: 3

Explanation:

• Pineapplefruit is a sorosis – a multiple fruit formed from the fusion of many flowers (inflorescence) along with the fleshy axis.
• Syconus– Fig fruit.
• Pome– Apple, pear.
• Therefore, the correct answer is Sorosis→ Option 3.

 

 

Question 36

Nutrient essential for diazotrophs (BNF) is:

1. N
2. P
3. K
4. Ca

Correct Answer: 2

Explanation:

• Diazotrophs(nitrogen-fixing bacteria) require phosphorus (P) for energy (ATP) needed for nitrogen fixation (nitrogenase requires 16 ATP per N₂).
• N– They fix nitrogen, but it is not an external nutrient requirement.
• K, Ca– Not specifically essential for BNF.
• Therefore, the correct answer is P→ Option 2.

 

 

Question 37

Poor man’s pulse crop is:

1. Cowpea
2. Black gram
3. Red gram
4. Horse gram

Correct Answer: 4

Explanation:

• Horse gram(Macrotyloma uniflorum) is often called the “poor man’s pulse crop” because it is highly drought-tolerant, requires low inputs, and is affordable.
• Cowpea, black gram, red gram– Also important pulses but not specifically called “poor man’s pulse”.
• Therefore, the correct answer is Horse gram→ Option 4.

 

 

Question 38

Crescograph is associated with:

1. Plant growth
2. Both a and b
3. Light intensity
4. Atmospheric pressure

Correct Answer: 1

Explanation:

• Crescograph– An instrument invented by Sir Jagadish Chandra Bose to measure plant growth (very small movements and growth rates).
• It is not directly associated with light intensity or atmospheric pressure.
• Therefore, the correct answer is Plant growth→ Option 1.

 

 

Question 39

Rice takes nitrogen under waterlogged condition in the form of:

1. NH₄⁺
2. NO₃⁻
3. N₂
4. NO₂⁻

Correct Answer: 1

Explanation:

• Under waterlogged (flooded) conditions, the soil becomes anaerobic, and nitrification is inhibited.
• Rice preferentially takes up ammonium (NH₄⁺)form of nitrogen.
• NO₃⁻– Taken up under aerobic conditions.
• Therefore, the correct answer is NH₄⁺→ Option 1.

 

Question 40

Tripping occurs in:

1. Pearl millet
2. Jowar
3. Lucerne
4. Mustard

Correct Answer: 3

Explanation:

• Tripping– The mechanism of pollen release in alfalfa (lucerne) (Medicago sativa) where the flower’s keel is tripped (opened) by insect pollinators (bees) to expose the sexual parts.
• It is essential for cross-pollination in lucerne.
• Pearl millet, jowar, mustard– Do not exhibit tripping.
• Therefore, the correct answer is Lucerne→ Option 3.