ICAR JRF Plant Science Practice Series Memory Based 2024 (Module 1) (81 – 120 MCQ) 

 

Question 81

Interculture in groundnut is avoided at:

1. Flowering stage
2. Seedling stage
3. Pegging stage
4. Pre-flowering stage

Correct Answer: 3

Explanation:

• Pegging stage– After fertilization, the gynophore (peg) penetrates the soil for pod development. Intercultural operations (hoeing, weeding) at this stage can damage the pegs and reduce yield.
• Therefore, the correct answer is Pegging stage→ Option 3.

 

 

Question 82

Bagasse, a by-product of sugar manufacturing industry, is used for the production of:

1. Paper
2. Alcohol
3. Confections
4. Glass

Correct Answer: 1

Explanation:

• Bagasse– The fibrous residue left after extracting juice from sugarcane. It is used in the manufacture of paper, wallboards, and biofuel.
• Therefore, the correct answer is Paper→ Option 1.

 

 

Question 83

Commonly used herbicide in wheat crop is:

1. Basalin
2. Atrazine
3. Isoproturon
4. Pendimethalin

Correct Answer: 3

Explanation:

• Isoproturon– A selective, systemic herbicide widely used for post-emergence control of grassy and broadleaf weeds in wheat.
• Atrazine– Used in maize.
• Basalin, pendimethalin– Used in other crops.
• Therefore, the correct answer is Isoproturon→ Option 3.

 

 

Question 84

In a cross between two homozygous parents, no genetic variation is present in:

1. F₁ generation
2. F₂ generation
3. F₄ generation
4. F generation

Correct Answer: 1

Explanation:

• When two homozygous parents(AA × aa) are crossed, the F₁ generation is uniform (all Aa) , showing no genetic variation (all progeny are identical).
• Genetic variation appears in F₂and subsequent generations due to segregation.
• Therefore, the correct answer is F₁ generation→ Option 1.

 

 

Question 85

Flag smut of wheat can be controlled by:

1. Seed treatment with vitavax
2. Spraying of vitavax
3. Soil application of vitavax
4. Thiram

Correct Answer: 1

Explanation:

• Flag smut of wheat(Urocystis agropyri) – A seedborne disease. It is controlled by seed treatment with Vitavax (carboxin) , a systemic fungicide.
• Thiram– A contact fungicide, less effective.
• Therefore, the correct answer is Seed treatment with vitavax→ Option 1.

 

 

Question 86

The fruit of rapeseed and mustard plant is known as: (Repeat of Q78)

1. Caryopsis
2. Grain
3. Capsule
4. Siliqua

Correct Answer: 4

Explanation:

• Siliqua (silique)– The characteristic fruit of Brassicaceae, including rapeseed and mustard.
• Therefore, the correct answer is Siliqua→ Option 4.

 

 

Question 87

The C:N ratio of compost should not be less than:

1. 20:1
2. 40:1
3. 100:1
4. 150:1

Correct Answer: 1

Explanation:

• The C:N ratioof mature compost should be less than 20:1 (typically 10:1 to 20:1). If it is higher, nitrogen immobilization can occur.
• Therefore, the correct answer is 20:1→ Option 1.

 

 

Question 88

The optimum moisture required for composting is:

1. 20-30%
2. 40-50%
3. 50-60%
4. 70-80%

Correct Answer: 3

Explanation:

• The optimum moisture contentfor composting is 50-60% (moisture content of a squeezed sponge).
• Below 40% – Microbial activity slows.
• Above 65% – Anaerobic conditions may develop.
• Therefore, the correct answer is 50-60%→ Option 3.

 

 

Question 89

Yellow vein mosaic of okra is transmitted by:

1. Aphid
2. White fly
3. Leaf hopper
4. Nematode

Correct Answer: 2

Explanation:

• Yellow vein mosaic of okra– Caused by a begomovirus, transmitted by the whitefly (Bemisia tabaci).
• Therefore, the correct answer is White fly→ Option 2.

 

 

Question 90

In India, domestic quarantine is in force for which of the following potato disease:

1. Wart disease
2. Black scurf
3. Powdery scab
4. Common scab

Correct Answer: 1

Explanation:

• Wart disease of potato(Synchytrium endobioticum) – A quarantine disease in India. Domestic quarantine is enforced to prevent its spread from infected areas (e.g., Darjeeling, West Bengal).
• Therefore, the correct answer is Wart disease→ Option 1.

 

 

Question 91

Phyllody is the:

1. Development of floral organs into leaf-like structures
2. Development of organs in an unexpected location
3. Overdevelopment of colour
4. Underdevelopment of colour

Correct Answer: 1

Explanation:

• Phyllody– A plant disease symptom where floral organs (sepals, petals, carpels, stamens) are transformed into leaf-like structures. It is often caused by phytoplasmas.
• Therefore, the correct answer is Development of floral organs into leaf-like structures→ Option 1.

 

 

Question 92

Foundation seed is produced from:

1. Certified seed
2. Farmer seed
3. Registered seed
4. Breeder seed

Correct Answer: 4

Explanation:

• Foundation seed– Produced from Breeder seed (the first stage of seed multiplication). It is the progeny of breeder seed and is used to produce certified seed.
• Therefore, the correct answer is Breeder seed→ Option 4.

 

 

Question 93

Blue colour tag is used in which class of seed:

1. Nuclear seed
2. Certified seed
3. Foundation seed
4. Registered seed

Correct Answer: 2

Explanation:

• In the Indian seed certification system:
  • Certified seed– Blue tag (or golden brown for some crops).
  • Foundation seed– White tag.
  • Breeder seed– Golden brown/azure blue.
  • Nucleus seed– No tag.
• Therefore, the correct answer is Certified seed→ Option 2.

 

 

Question 94

The process of influencing people towards achieving a common goal is called:

1. Co-rumination
2. Leadership
3. D’sment (likely misprint)
4. Print media

Correct Answer: 2

Explanation:

• Leadership– The process of influencing and guiding people towards achieving a common goal.
• Therefore, the correct answer is Leadership→ Option 2.

 

 

Question 95

Learning to use a sprayer correctly requires repeated trying of the instrument. The extension principle followed is:

1. Principle of motivation
2. Principle of attitude
3. Principle of satisfaction
4. Principle of practice

Correct Answer: 4

Explanation:

• Principle of practice– Learning a skill (like using a sprayer correctly) requires repeated practice (trying the instrument multiple times).
• Therefore, the correct answer is Principle of practice→ Option 4.

 

 

Question 96

Whip smut of sugarcane is caused by:

1. Ustilago nuda
2. Ustilago hordei
3. Urocystis agropyri
4. Ustilago scitaminea

Correct Answer: 4

Explanation:

• Whip smut of sugarcane– Caused by Ustilago scitaminea (syn. Sporisorium scitamineum). It produces a long, black, whip-like structure from the central shoot.
• Ustilago nuda– Loose smut of wheat/barley.
• Ustilago hordei– Covered smut of barley.
• Urocystis agropyri– Flag smut of wheat.
• Therefore, the correct answer is Ustilago scitaminea→ Option 4.

 

 

Question 97

Mushrooms belong to:

1. Basidiomycetes
2. Ascomycetes
3. Zygomycetes
4. None of these

Correct Answer: 1

Explanation:

• Most edible mushrooms(e.g., Agaricus, Pleurotus) belong to the class Basidiomycetes (produce basidiospores on basidia).
• Some mushrooms (e.g., morels) are Ascomycetes.
• Therefore, the correct answer is Basidiomycetes→ Option 1.

 

 

Question 98

In chemical sterilization, chlorine is used for:

1. Treating burns
2. Water disinfection
3. Skin disinfection
4. Sterilizing instruments

Correct Answer: 2

Explanation:

• Chlorine(in various forms like sodium hypochlorite, chlorine gas) is widely used for water disinfection (drinking water, swimming pools, wastewater treatment).
• Therefore, the correct answer is Water disinfection→ Option 2.

 

Question 99

The C:N ratio of compost should not be less than: (Repeat of Q87)

1. 20:1
2. 40:1
3. 100:1
4. 150:1

Correct Answer: 1

Explanation:

• Mature compost should have a C:N ratio of less than 20:1(typically 10:1 to 20:1).
• Therefore, the correct answer is 20:1→ Option 1.

 

 

Question 100

The optimum moisture required for composting is: (Repeat of Q88)

1. 20-30%
2. 40-50%
3. 50-60%
4. 70-80%

Correct Answer: 3

Explanation:

• The optimum moisture for composting is 50-60%.
• Therefore, the correct answer is 50-60%→ Option 3.

 

 

Question 101

Yellow vein mosaic of okra is transmitted by: (Repeat of Q89)

1. Aphid
2. White fly
3. Leaf hopper
4. Nematode

Correct Answer: 2

Explanation:

• Yellow vein mosaic of okra– Transmitted by whitefly (Bemisia tabaci).
• Therefore, the correct answer is White fly→ Option 2.

 

 

Question 102

In India, domestic quarantine is in force for which of the following potato disease: (Repeat of Q90)

1. Wart disease
2. Black scurf
3. Powdery scab
4. Common scab

Correct Answer: 1

Explanation:

• Wart disease of potato– A quarantine disease in India.
• Therefore, the correct answer is Wart disease→ Option 1.

 

 

Question 103

Phyllody is the: 

1. Development of floral organs into leaf-like structures
2. Development of organs in an unexpected location
3. Overdevelopment of colour
4. Underdevelopment of colour

Correct Answer: 1

Explanation:

• Phyllody– Transformation of floral parts into leaf-like structures.
• Therefore, the correct answer is Development of floral organs into leaf-like structures→ Option 1.

 

 

Question 104

Foundation seed is produced from: (Repeat of Q92)

1. Certified seed
2. Farmer seed
3. Registered seed
4. Breeder seed

Correct Answer: 4

Explanation:

• Foundation seed is produced from Breeder seed.
• Therefore, the correct answer is Breeder seed→ Option 4.

 

 

Question 105

Blue colour tag is used in which class of seed: (Repeat of Q93)

1. Nuclear seed
2. Certified seed
3. Foundation seed
4. Registered seed

Correct Answer: 2

Explanation:

• Certified seed– Blue tag.
• Therefore, the correct answer is Certified seed→ Option 2.

 

 

Question 106

The process of influencing people towards achieving a common goal is called: (Repeat of Q94)

1. Co-rumination
2. Leadership
3. D’sment
4. Print media

Correct Answer: 2

Explanation:

• Leadership– Influencing people towards a common goal.
• Therefore, the correct answer is Leadership→ Option 2.

 

 

Question 107

Learning to use a sprayer correctly requires repeated trying of the instrument. The extension principle followed is: (Repeat of Q95)

1. Principle of motivation
2. Principle of attitude
3. Principle of satisfaction
4. Principle of practice

Correct Answer: 4

Explanation:

• Principle of practice– Repeated practice is needed to learn a skill.
• Therefore, the correct answer is Principle of practice→ Option 4.

 

 

Question 108

A homozygous line developed by self fertilization in a cross pollinated crop is termed as:

1. Pure line
2. Inbred
3. Clone
4. Mutant

Correct Answer: 2

Explanation:

• Inbred line– A homozygous line developed by repeated selfing (self-fertilization) in a cross-pollinated crop.
• Pure line– Term used for self-pollinated crops.
• Clone– Vegetatively propagated.
• Therefore, the correct answer is Inbred→ Option 2.

 

 

Question 109

Mendelian population means:

1. Self pollinated population
2. Inbred population
3. Random mating population
4. Hybrid population

Correct Answer: 3

 

Explanation:

• Mendelian population– A population of sexually reproducing individuals that interbreed randomly (random mating), sharing a common gene pool.
• Therefore, the correct answer is Random mating population→ Option 3.

 

 

Question 110

A haploid contains:

1. Gametic chromosome number
2. Basic chromosome number
3. Somatic chromosome number
4. Polyploid chromosome number

Correct Answer: 1

Explanation:

• Haploid (n)– Contains the gametic chromosome number (one set of chromosomes, as in gametes).
• Basic chromosome number (x)– Refers to the base number in a polyploid series.
• Therefore, the correct answer is Gametic chromosome number→ Option 1.

 

 

Question 111

The gametic chromosome number of a true diploid species is called:

1. Basic number
2. Haploid number
3. Somatic number
4. None of these

Correct Answer: 2

Explanation:

• In a true diploid species, the gametic chromosome numberis the haploid number (n) .
• Basic number (x)– May be different in polyploids.
• Therefore, the correct answer is Haploid number→ Option 2.

 

 

Question 112

Isogenic lines are used to develop:

1. Hybrids
2. Composites
3. Multilines
4. Synthetics

Correct Answer: 3

Explanation:

• Isogenic lines– Genetically identical except for a specific gene. They are used to develop multilines (a mixture of isogenic lines with different resistance genes).
• Therefore, the correct answer is Multilines→ Option 3.

 

 

Question 113

In a hybridization programme, a recurrent parent is used in:

1. Bulk method
2. Back cross method
3. Pedigree method
4. Mass selection

Correct Answer: 2

Explanation:

• Back cross method– Uses a recurrent parent (the elite variety) that is repeatedly crossed with the donor parent to transfer a specific gene.
• Therefore, the correct answer is Back cross method→ Option 2.

 

 

Question 114

Kreb’s cycle begins with:

1. Glycogen
2. Lysin
3. Succinic acid
4. Acetyl CoA

Correct Answer: 4

Explanation:

• Krebs cycle (TCA cycle)– Begins with the condensation of Acetyl CoA (2-carbon) with oxaloacetate (4-carbon) to form citrate (6-carbon).
• Therefore, the correct answer is Acetyl CoA→ Option 4.

 

 

Question 115

The following is a naturally occurring growth inhibitor:

1. NAA
2. GA₃
3. ABA
4. IAA

Correct Answer: 3

Explanation:

• ABA (Abscisic acid)– A naturally occurring plant growth inhibitor (promotes dormancy, stomatal closure, inhibits growth).
• NAA, IAA– Auxins (growth promoters).
• GA₃– Gibberellin (growth promoter).
• Therefore, the correct answer is ABA→ Option 3.

 

 

Question 116

Seeds swell when placed in water due to:

1. Osmosis
2. Imbibition
3. Hydrolysis
4. Plasmolysis

Correct Answer: 2

Explanation:

• Imbibition– The absorption of water by hydrophilic colloids (cellulose, hemicellulose, proteins) in the seed coat, causing seeds to swell.
• Osmosis– Movement of water across a semipermeable membrane.
• Therefore, the correct answer is Imbibition→ Option 2.

 

 

Question 117

An enzyme excreted by a micro-organism into the environment is called:

1. Exoenzyme
2. Endoenzyme
3. Coenzyme
4. Ligase enzyme

Correct Answer: 1

Explanation:

• Exoenzyme– An enzyme that is secreted (excreted) by a microorganism into the external environment to break down large molecules (e.g., cellulase, amylase).
• Endoenzyme– Functions inside the cell.
• Therefore, the correct answer is Exoenzyme→ Option 1.

 

 

Question 118

Flag smut of wheat can be controlled by: (Repeat of Q85)

1. Seed treatment with vitavax
2. Spraying of vitavax
3. Soil application of vitavax
4. Thiram

Correct Answer: 1

Explanation:

• Flag smut of wheat – Controlled by seed treatment with vitavax (carboxin).
• Therefore, the correct answer is Seed treatment with vitavax→ Option 1.

 

 

Question 119

Symbiotic nitrogen fixing bacteria occur in the genus: (Repeat of Q74)

1. Xanthomonas
2. Pseudomonas
3. Rhizobium
4. Azotobacter

Correct Answer: 3

Explanation:

• Rhizobium– Symbiotic nitrogen fixer.
• Therefore, the correct answer is Rhizobium→ Option 3.

 

 

Question 120

Sauerkraut is a fermented food product obtained from: (Repeat of Q75)

1. Onion
2. Olives
3. Cabbage
4. Cauliflower

Correct Answer: 3

Explanation:

• Sauerkraut– Fermented cabbage.
• Therefore, the correct answer is Cabbage→ Option 3.