ICAR JRF Plant Science Practice Series Memory Based 2024 (Module 1) (41 – 80 MCQ) 

 

Question 40

Cauliflower mosaic virus is an:

1. dsDNA
2. ssRNA
3. dsRNA
4. ssDNA

Correct Answer: 1

 

Explanation:

• Cauliflower mosaic virus (CaMV)is a double-stranded DNA (dsDNA) virus, belonging to the family Caulimoviridae.
• It is one of the few plant viruses with a dsDNA genome (most plant viruses have ssRNA genomes).
• ssRNA– Most plant viruses (e.g., TMV, potyviruses).
• dsRNA– Reoviruses (e.g., rice dwarf virus).
• ssDNA– Geminiviruses (e.g., cotton leaf curl virus).

 

 

Question 41

Breeding method to improve a specific character in released variety:

1. Pedigree method
2. Bulk method
3. SSD method
4. Back cross method

Correct Answer: 4

 

Explanation:

• Backcross method– Used to transfer a specific character (e.g., disease resistance, quality trait) from a donor parent into an already released (elite) variety (recurrent parent).
• Pedigree method– For selecting superior segregants from a cross between two adapted parents.
• Bulk method– For population improvement under natural selection.
• SSD (Single Seed Descent) method– For rapid generation advancement.

 

 

Question 42

Pedogenesis is the study of:

1. Soil formation
2. Rock formation
3. Soil structure formation
4. Study of fertility status

Correct Answer: 1

 

Explanation:

• Pedogenesis– The scientific study of soil formation and development processes.
• Rock formation– Petrogenesis.
• Soil structure formation– Part of pedogenesis but not the full definition.
• Study of fertility status– Soil fertility evaluation.

 

 

Question 43

Highest protein content is found in:

1. Soybean
2. Gram
3. Rajmah
4. Mungbean

Correct Answer: 1

 

Explanation:

• Soybean (Glycine max)– Contains approximately 38-42% protein (highest among the given options).
• Gram (Chickpea)– ~20-22% protein.
• Rajmah (Kidney bean)– ~22-24% protein.
• Mungbean– ~24-26% protein.

 

 

Question 44

Which test is used for comparing two means from independent samples?

1. F-test
2. t-test
3. Z-test
4. Chi-square test

Correct Answer: 2

 

Explanation:

• t-test– Used to compare the means of two independent samples (e.g., treatment vs control).
• F-test– Compares variances; used in ANOVA.
• Z-test– Used for large sample sizes when population variance is known.
• Chi-square test– Tests association between categorical variables (goodness-of-fit, independence).

 

 

Question 45

Which one of the following is a Kharif crop?

1. Pearl millet
2. Lentil
3. Mustard
4. Wheat

Correct Answer: 1

 

Explanation:

• Kharif crops– Grown during the rainy season (June-July to September-October).
• Pearl millet (Bajra)– A major kharif crop.
• Lentil, Mustard, Wheat– Rabi crops (grown in winter).

 

 

Question 46

Which one of the following is used to test the goodness-of-fit of a distribution?

1. Normal test
2. t-test
3. Chi-square test
4. F-test

Correct Answer: 3

 

Explanation:

• Chi-square (χ²) test– Used to test goodness-of-fit (how well an observed distribution fits an expected distribution).
• Normal test– Tests if data follows normal distribution.
• t-test– Compares means.
• F-test– Compares variances.

 

 

Question 47

Conservation Agriculture’ forms a component of:

1. Sustainable agriculture
2. Extensive agriculture
3. Intensive agriculture
4. Organic farming

Correct Answer: 1

 

Explanation:

• Conservation Agriculture (CA)– A farming system based on minimum soil disturbance, permanent soil cover, and crop rotation. It is a key component of sustainable agriculture.
• Extensive agriculture– Low input, large land area.
• Intensive agriculture– High input, high yield per unit area.
• Organic farming– Avoids synthetic inputs; CA may include some synthetic inputs.

 

 

Question 48

Brassica juncea has been evolved after the hybridization between:

1. nigraand B. campestris
2. nigraand B. oleracea
3. campestrisand B. oleracea
4. campestrisand 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 U– Describes the genomic relationships among Brassica
• nigra × B. oleracea– Gives B. carinata.
• campestris × B. oleracea– Gives B. napus.

 

 

Question 49

Which organelle is found with half unit membrane?

1. Oleosome
2. Ribosome
3. Glyoxysome
4. Peroxisome

Correct Answer: 1

 

Explanation:

• Oleosome (lipid body)– A spherical organelle for lipid storage. It is surrounded by a half-unit membrane (monolayer of phospholipids).
• Ribosome– Non-membranous organelle.
• Glyoxysome, Peroxisome– Single membrane-bound organelles (full unit membrane).

 

 

Question 50

Suicidal germination takes place in:

1. Dodder
2. Striga
3. Loranthus
4. Dendrophthoe falcata

Correct Answer: 2

 

Explanation:

• Suicidal germination– When a parasitic plant (like Striga) germinates in the absence of a host, leading to its death.
• Striga(witchweed) – A root parasite of cereals (maize, sorghum, millet). Its seeds germinate in response to strigolactones released by host roots. Without a host, germination is “suicidal”.
• Dodder (Cuscuta)– Stem parasite.
• Loranthus– Stem parasite.
• Dendrophthoe falcata– Mistletoe; stem parasite.

 

 

Question 51

Granite, an important rock, is classified as:

1. Igneous rock
2. Metamorphic rock
3. Sedimentary rock
4. Hybrid rock

Correct Answer: 1

 

Explanation:

• Granite– A coarse-grained, intrusive igneous rock composed primarily of quartz, feldspar, and mica.
• Metamorphic rock– Formed from existing rocks by heat and pressure (e.g., marble, slate).
• Sedimentary rock– Formed from deposited sediments (e.g., sandstone, limestone).

 

 

Question 52

Blind tillage refers to:

1. Summer ploughing
2. Hoeing in standing crop rows
3. Primary tillage
4. Hoeing before germination

Correct Answer: 4

 

Explanation:

• Blind tillage– A shallow tillage operation before crop emergence (after sowing but before germination) to control small weeds and break soil crust.
• Summer ploughing– Deep ploughing during summer.
• Hoeing in standing crop rows– Intercultivation after emergence.
• Primary tillage– Initial soil preparation (ploughing, discing).

 

 

Question 53

Cell linkage theory was proposed by:

1. Schleiden and Schwann
2. Nageli
3. Hooke
4. Linnaeus

Correct Answer: 2

 

Explanation:

• Cell linkage theory– Proposed by Carl Nägeli, who suggested that cells are formed from pre-existing cells and that the nucleus is important in cell division.
• Schleiden and Schwann– Proposed the Cell Theory (all living organisms are composed of cells).
• Hooke– Discovered cells (cork).
• Linnaeus– Father of taxonomy.

 

 

Question 54

Which of the following is a 5C sugar?

1. Galactose
2. Ribose
3. Glucose
4. Mannose

Correct Answer: 2

 

Explanation:

• Ribose– A pentose (5-carbon sugar) found in RNA and various nucleotides.
• Galactose, Glucose, Mannose– Hexoses (6-carbon sugars) .

 

 

Question 55

During seed development, if the mechanical tissue develops from the outer epidermis of the outer integument, then the seed is called as:

1. Exotestal
2. Mesotestal
3. Endotestal
4. Exotegmic

Correct Answer: 1

 

Explanation:

• Exotestal seed– The mechanical (sclerenchymatous) tissue develops from the outer epidermis of the outer integument.
• Mesotestal– From the middle layer of the outer integument.
• Endotestal– From the inner epidermis of the outer integument.
• Exotegmic– From the outer epidermis of the inner integument (tegmen).

 

 

Question 56

Who found that a peculiar regularity exists in the ratios of nitrogenous bases of double stranded DNA?

1. James Watson and Francis Crick
2. Rosalind Franklin
3. Erwin Chargaff
4. Waclaw Szybalski

Correct Answer: 3

 

Explanation:

• Erwin Chargaff (1950)– Discovered Chargaff’s rules: In double-stranded DNA, A = T and G = C, and the ratio of purines to pyrimidines is 1:1.
• Watson and Crick– Proposed the double helix structure (1953).
• Rosalind Franklin– Provided X-ray diffraction images of DNA.
• Waclaw Szybalski– Worked on DNA hybridization.

 

 

Question 57

Crossing over between non-sister chromatids of homologous chromosomes takes place during:

1. Leptotene
2. Pachytene
3. Diplotene
4. Zygotene

Correct Answer: 2

 

Explanation:

• Crossing over– Exchange of genetic material between non-sister chromatids of homologous chromosomes occurs during the pachytene stage of prophase I of meiosis.
• Leptotene– Chromosomes condense.
• Zygotene– Pairing (synapsis) begins.
• Pachytene– Crossing over occurs.
• Diplotene– Chiasmata visible, homologous chromosomes begin to separate.

 

 

Question 58

Amylopectin is a carbohydrate which is:

1. Monosaccharide
2. Disaccharide
3. Oligosaccharide
4. Polysaccharide

Correct Answer: 4

 

Explanation:

• Amylopectin– A polysaccharide (branched polymer of glucose units) and a component of starch (along with amylose).
• Monosaccharide– Single sugar unit (e.g., glucose).
• Disaccharide– Two sugar units (e.g., sucrose).
• Oligosaccharide– 2-10 sugar units.

 

 

Question 59

The megaspore mother cell is:

1. Haploid
2. Diploid
3. Tetraploid
4. Triploid

Correct Answer: 2

 

Explanation:

• Megaspore mother cell (MMC)– A diploid (2n) cell in the ovule that undergoes meiosis to produce four haploid megaspores.
• Of these, one functional megaspore develops into the female gametophyte (embryo sac).
• Haploid– Megaspores, gametes.
• Tetraploid, Triploid– Not applicable to MMC.

 

 

Question 60

During photosynthesis, oxygen is generated from:

1. Carbon dioxide only
2. Water only
3. Both water and carbon dioxide
4. Phosphoglycerate

Correct Answer: 2

 

Explanation:

• In photosynthesis, oxygen (O₂) is generated from the photolysis (splitting) of water (H₂O)in the light reaction (Photosystem II).
• The oxygen released comes from water, not from carbon dioxide.
• Carbon dioxide– Fixed into organic compounds via the Calvin cycle (does not release O₂).
• Phosphoglycerate– An intermediate in the Calvin cycle.

 

 

Question 61

Group of salts found in sodic soils:

1. Na₂CO₃ + Na₂SO₄
2. Na₂CO₃ + NaHCO₃
3. NaCl + Na₂CO₃
4. NaCl + Na₂SO₄

Correct Answer: 2

 

Explanation:

• Sodic soils(alkali soils) are characterized by high concentrations of sodium carbonate (Na₂CO₃) and sodium bicarbonate (NaHCO₃) .
• These salts cause high pH (>8.5) and poor soil structure.
• NaCl + Na₂SO₄– Found in saline soils (high electrical conductivity, pH <8.5).

 

 

Question 62

Major micronutrient deficiency in tobacco is due to:

1. Boron
2. Manganese
3. Copper
4. Molybdenum

Correct Answer: 1

 

Explanation:

• Boron deficiencyis a major micronutrient deficiency in tobacco, causing top splitting, brittle leaves, and reduced quality.
• Manganese, copper, molybdenum– Also important but not the major deficiency in tobacco.

 

 

Question 63

Which of the following does NOT apply to SRI method of paddy cultivation?

1. Reduced water application
2. Reduced plant density
3. Increased application of chemical fertilizers
4. Reduced age of seedlings

Correct Answer: 3

 

Explanation:

• System of Rice Intensification (SRI)– A method that uses:
  • Reduced water application(alternate wetting and drying)
  • Reduced plant density(wider spacing, single seedling per hill)
  • Reduced age of seedlings(younger seedlings, 8-12 days old)
  • Organic matter application(not increased chemical fertilizers)
• Increased application of chemical fertilizers– NOT a feature of SRI; it emphasizes organic nutrient management.

 

 

Question 64

Photoperiodism is:

1. Bending of shoot towards source of light
2. Effect of light/dark durations on physiological processes
3. Movement of chloroplast in cell in response to light
4. Effect of light on chlorophyll synthesis

Correct Answer: 2

 

Explanation:

• Photoperiodism– The response of plants to the relative lengths of light (day) and dark (night) periods , influencing flowering, dormancy, and other physiological processes.
• Bending towards light– Phototropism.
• Movement of chloroplast– Phototaxis.
• Effect of light on chlorophyll synthesis– Light-induced chlorophyll formation.

 

 

Question 65

Which of the following is commonly referred to as muriate of potash?

1. Potassium nitrate
2. Potassium sulphide
3. Potassium chloride
4. DAP

Correct Answer: 3

 

Explanation:

• Muriate of potash (MOP)– Common name for potassium chloride (KCl) , a major potash fertilizer.
• Potassium nitrate (KNO₃)– Nitrate of potash.
• Potassium sulphide (K₂S)– Not used as a fertilizer.
• DAP– Diammonium phosphate (nitrogen-phosphorus fertilizer).

 

 

Question 66

The enzyme responsible for the fixation of CO₂ in mesophyll cells of C-4 plants is:

1. Malic enzyme
2. Phosphoenol pyruvate carboxylase
3. Phosphoenol pyruvate
4. RuBP carboxylase

Correct Answer: 2

 

Explanation:

• In C4 plants, CO₂ is initially fixed in mesophyll cellsby the enzyme Phosphoenol pyruvate carboxylase (PEP carboxylase) , which combines CO₂ with phosphoenol pyruvate (PEP) to form oxaloacetate (4C compound).
• Malic enzyme– Decarboxylates malate in bundle sheath cells.
• RuBP carboxylase (Rubisco)– Fixes CO₂ in bundle sheath cells (C4 plants) or in mesophyll (C3 plants).

 

 

Question 67

Seedless banana is an:

1. Autotriploid
2. Autotetraploid
3. Allotriploid
4. Allotetraploid

Correct Answer: 1

 

Explanation:

• Seedless banana(commercial edible banana) is an autotriploid (3n) derived from hybridization within the same species (Musa acuminata).
• Triploids are sterile due to unbalanced gametes during meiosis, producing seedless fruits (parthenocarpy).
• Autotetraploid– Four sets from the same species.
• Allotriploid– From hybridization of different species (e.g., some bananas are also allotriploid AAA or AAB genomes).

 

 

Question 68

Variation in diversity among plant population is influenced most by:

1. Breeding systems
2. Geographic range
3. Mode of reproduction
4. Taxonomic status

Correct Answer: 3

 

Explanation:

• Mode of reproduction– Whether a plant is self-pollinated, cross-pollinated, or clonally propagated has the greatest influence on genetic diversity within and among populations.
• Cross-pollinated species have higher genetic diversity than self-pollinated species.
• Breeding systems, geographic range, taxonomic status– Also important but less influential than mode of reproduction.

 

 

Question 69

The cDNA libraries can be prepared by isolating:

1. tRNA
2. mRNA
3. DNA
4. rDNA

Correct Answer: 2

 

Explanation:

• cDNA (complementary DNA)libraries are prepared by isolating mRNA from cells, then using reverse transcriptase to synthesize complementary DNA (cDNA).
• The cDNA represents the expressed genes (transcriptome) of the cell.
• tRNA, DNA, rDNA– Not used for cDNA library preparation.

 

 

Question 70

Oxysomes occurs in:

1. Plastids
2. Golgi bodies
3. Endoplasmic reticulum
4. Mitochondria

Correct Answer: 4

 

Explanation:

• Oxysomes (F₁ particles)– Spherical structures on the inner mitochondrial membrane that contain ATP synthase (responsible for ATP synthesis during oxidative phosphorylation).
• Plastids– Contain thylakoids, stroma.
• Golgi bodies– Contain cisternae.
• Endoplasmic reticulum– Contains ribosomes (rough ER) or smooth membranes.

 

 

Question 71

First pigeonpea hybrid developed through GMS in India:

1. IPCH-8
2. ICPH-8
3. IHCP-8
4. IHPC-8

Correct Answer: 2

 

Explanation:

• ICPH-8 (ICRISAT Pigeonpea Hybrid-8)– The first pigeonpea hybrid developed using Genetic Male Sterility (GMS) in India.
• It was released for commercial cultivation.
• The other options are incorrect designations.

 

 

Question 72

First cotton hybrid developed in the world:

1. H8
2. H6
3. H4
4. Varalaxmi

Correct Answer: 3

 

Explanation:

• H4– The first cotton hybrid developed in the world (in India) by  C.T. Patel (1970) at the Cotton Research Station, Surat.
• It was a hybrid between Gossypium hirsutumand Gossypium barbadense.
• H6, H8– Later cotton hybrids.
• Varalaxmi– Another cotton hybrid, not the first.

 

 

Question 73

Which of the following is mainly responsible for eutrophication?

1. Phosphate
2. Nitrate
3. Carbonate
4. Sulphate

Correct Answer: 1

 

Explanation:

• Phosphate (phosphorus)is the primary limiting nutrient responsible for eutrophication of freshwater bodies (excessive algal blooms).
• While nitratealso contributes, phosphorus is often the key limiting factor.
• Carbonate, sulphate– Not major causes of eutrophication.

 

 

Question 74

The conversion of CO₂ and H₂O into organic compounds using energy from light is:

1. Photorespiration
2. Fermentation
3. Glycolysis
4. Photosynthesis

Correct Answer: 4

 

Explanation:

• Photosynthesis– The process by which plants convert CO₂ and H₂O into organic compounds (glucose) using light energy (via chlorophyll).
• Photorespiration– Light-dependent oxygen fixation (inefficient).
• Fermentation– Anaerobic breakdown of sugars.
• Glycolysis– Breakdown of glucose to pyruvate.

 

 

Question 75

Nick translation is directly involved in which of the following process:

1. RNA to DNA
2. DNA to RNA
3. DNA to DNA
4. RNA to protein

Correct Answer: 3

 

Explanation:

• Nick translation– A technique for labeling DNA (DNA to DNA) by introducing nicks (breaks) into one strand and using DNA polymerase I to synthesize new DNA while displacing existing strands.
• It is used to prepare radioactive or fluorescent probes for hybridization.
• RNA to DNA– Reverse transcription.
• DNA to RNA– Transcription.
• RNA to protein– Translation.

 

 

Question 76

The tag colour of foundation seed is:

1. Black
2. Blue
3. White
4. Yellow

Correct Answer: 3

 

Explanation:

• In the Indian seed certification system:
  • Foundation seed– White tag
  • Certified seed– Blue tag (or golden brown for some crops)
  • Breeder seed– Golden brown tag (or azure blue)
  • Nucleus seed– No tag
• Therefore, the correct answer is White→ Option 3.

 

 

Question 77

Aromatic rice variety Texmati is patented by:

1. Mahyco
2. Calgene
3. Rice Tech
4. Pioneer Hybrid

Correct Answer: 3

 

Explanation:

• Texmati– An aromatic rice variety (cross between basmati and American long-grain rice) patented by Rice Tech Inc. (USA).
• Mahyco– Indian seed company (Bt cotton).
• Calgene– Developed Flavr Savr tomato.
• Pioneer Hybrid– Major seed company (maize, soybean).

 

 

Question 78

Square root of variance is:

1. Coefficient of variation
2. Standard deviation
3. Mean
4. Median

Correct Answer: 2

 

Explanation:

• Standard deviation (σ)– The square root of variance (σ²).
• Coefficient of variation (CV)– (Standard deviation / mean) × 100.
• Mean– Average of observations.
• Median– Middle value.

 

 

Question 79

Which of the following method is an ultimate source of creating genetic variation?

1. Hybridization
2. Selection
3. Introduction
4. Mutation

Correct Answer: 4

 

Explanation:

• Mutation– The ultimate source of genetic variation because it creates new alleles (changes in DNA sequence).
• Hybridization– Combines existing variation from different parents.
• Selection– Acts on existing variation.
• Introduction– Brings variation from other populations.

 

 

Question 80

Backcross method of selection is used for improving traits which is:

1. Oligogenic
2. Polygenic
3. Disease resistance
4. Test with high heritability

Correct Answer: 1

 

Explanation:

• Oligogenic traits– Controlled by one or a few genes (qualitative traits), such as disease resistance, plant color, etc. These are ideal for backcross method.
• Polygenic traits– Controlled by many genes (quantitative traits); backcross method is not efficient for these.
• Disease resistance– Example of oligogenic trait, but the question asks for the trait type.