ICAR JRF Agronomy Practice Series Memory Based 2019 (Module 2) (41 – 80 MCQ)
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Question 41
Electrical conductivity of good quality irrigation water must be:
- < 1.5 dS/m
- 5 – 2.5 dS/m
- 3 – 5.0 dS/m
- 0 dS/m
Correct Answer: 1
Detailed Explanation:
- Electrical Conductivity (EC)measures the concentration of soluble salts in water. The unit is decisiemens per metre (dS/m) or millimhos per centimetre (mmho/cm); 1 dS/m = 1 mmho/cm.
- Classification of irrigation water based on EC (USDA Salinity Laboratory):
|
EC (dS/m) |
Salinity Class |
Suitability |
|
< 0.7 |
Low |
Excellent |
|
0.7 – 1.5 |
Medium |
Good (suitable for most crops) |
|
1.5 – 3.0 |
High |
Moderate – requires leaching and salt-tolerant crops |
|
3.0 – 6.0 |
Very High |
Suitable only for very salt-tolerant crops |
|
> 6.0 |
Extremely High |
Unsuitable |
- Good quality irrigation water should have EC < 1.5 dS/m→ Option 1.
Question 42
Demand and supply based water requirement of a crop is:
- WR = IR + ER
- WR = IR + ER + S
- WR = R – IR
- WR = IR + ER + ET
Correct Answer: 2
Explanation:
- Water Requirement (WR)of a crop is the total amount of water needed from all sources (rainfall + irrigation) to meet the crop’s evapotranspiration (ET) needs and other losses.
- The standard equation is: Water Requirement=Evapotranspiration+Irrigation Requirement+Effective Rainfall+LossesWater Requirement=Evapotranspiration+Irrigation Requirement+Effective Rainfall+Losses
- Or more simply: WR=IR+ER+(storage/seepage)WR=IR+ER+(storage/seepage)
- Option 2 includes S (Storage/Seepage)– this represents water stored in the root zone and/or losses. The demand-supply approach considers this term.
- Option 4 (WR = IR + ER + ET) is incorrect because ET is already included in IR and ER conceptually – double counting.
- As per the exam key, Option 2is correct.
Question 43
Darcy’s law governs:
- Soil hydraulic conductivity
- Soil Infiltration rate
- Soil permeability
- Soil penetrability
Correct Answer: 1
Detailed Explanation:
- Darcy’s lawis a fundamental equation for fluid flow through porous media. It states: Q=K⋅i⋅AQ=K⋅i⋅A
Where:
- Q = flow rate (m³/s)
- K = hydraulic conductivity (m/s) – a property of the soil and fluid
- i = hydraulic gradient (dimensionless)
- A = cross-sectional area (m²)
- Darcy’s law is used to measure or describe hydraulic conductivity(K), which indicates how easily water moves through soil.
- Infiltration rate (2)is the rate at which water enters the soil surface – it is influenced by hydraulic conductivity but not directly governed by Darcy’s law.
- Soil permeability (3)is similar to hydraulic conductivity but specifically for saturated conditions.
- Soil penetrability (4)relates to root penetration, not water flow.
- Hence, Option 1is correct.
Question 44
Plant micronutrients are:
- Fe, Zn, Mn, Cu & B
- Ca, Zn, Ni & Cl
- Mg, Mn, Cu & Fe
- N, P, K & S
Correct Answer: 1
Explanation:
- Micronutrients(also called trace elements) are required by plants in very small amounts (less than 100 ppm dry matter).
- The eight essential micronutrients recognised by plant physiologists (Arnon & Stout criteria) are:
|
Element |
Symbol |
|
Iron |
Fe |
|
Manganese |
Mn |
|
Zinc |
Zn |
|
Copper |
Cu |
|
Boron |
B |
|
Molybdenum |
Mo |
|
Chlorine |
Cl |
|
Nickel |
Ni |
- Option 1 lists Fe, Zn, Mn, Cu, B– all are micronutrients (Cl, Mo, Ni are missing but the set is still correct).
- Option 2 includes Ca(macronutrient).
- Option 3 includes Mg(macronutrient).
- Option 4 lists only macronutrients(N, P, K, S).
- Hence, Option 1is correct.
Question 45
One hectare-cm of water is equal to:
- 1000 litres
- 10,000 litres
- 1,00,000 litres
- 10,00,000 litres
Correct Answer: 3
Calculation & Explanation:
- 1 hectare= 10,000 m²
- 1 cm= 0.01 m
- Volume = Area × Depth = 10,000 m² × 0.01 m = 100 m³
- 1 m³= 1,000 litres
- Therefore, 100 m³ = 100 × 1,000 = 1,00,000 litres
- Hence, 1 ha-cm = 1,00,000 litres→ Option 3.
Question 46
If % P₂O₅ in a fertilizer is 46, % P will be:
- 0
- 7
- 2
- 4
Correct Answer: 3
Calculation & Explanation:
- P₂O₅ (phosphorus pentoxide) is the chemical form used to express phosphate content in fertilizers.
- Molecular weight of P₂O₅ = (2×31) + (5×16) = 62 + 80 = 142 g/mol
- Weight of P in P₂O₅ = 2×31 = 62 g
- Percentage of P in P₂O₅ = (62 / 142) × 100 ≈ 66%
- Hence, Option 3 (20.2%)is correct.
Question 47
Plants growing under high salt concentration are called:
- Glycophytes
- Halophytes
- Ephemerals
- Mesophytes
Correct Answer: 2
Explanation:
- Halophytes(Greek halos = salt, phyton = plant) are plants that naturally grow in high salinity conditions, such as mangroves, salt marshes, and saline deserts.
- They have special adaptations:
-
- Salt secretion through glands
- Succulence (dilution of salts)
- Salt exclusion by roots
- Accumulation of compatible solutes (proline, glycine betaine)
- Glycophytes (1)– salt-sensitive plants (most crop plants).
- Ephemerals (3)– short-lived plants that complete life cycle quickly.
- Mesophytes (4)– plants requiring moderate moisture conditions.
- Hence, Option 2is correct.
Question 48
Synthetic auxins are:
- IBA, NAA and 2,4-D
- 2,4-D, MCPA and MH
- 2,4-D, MCPA and PMA
- IAA, IBA and NAA
Correct Answer: 1
Explanation:
- Auxinsare plant hormones that regulate growth (cell elongation, apical dominance, root initiation).
- Natural auxin– Indole-3-acetic acid (IAA).
- Synthetic auxinsare chemically synthesised compounds with auxin-like activity. They are used as:
- Rooting hormones (IBA, NAA)
- Herbicides (2,4-D, MCPA, dicamba)
- List of synthetic auxins:
|
Compound |
Use |
|
IBA (Indole-3-butyric acid) |
Rooting hormone |
|
NAA (Naphthalene acetic acid) |
Rooting hormone, fruit thinning |
|
2,4-D (2,4-dichlorophenoxyacetic acid) |
Broadleaf herbicide |
|
MCPA |
Broadleaf herbicide |
- Option 1 (IBA, NAA, 2,4-D) – all synthetic auxins.
- Option 4 includes IAA (natural auxin).
- Option 2 includes MH (maleic hydrazide – a growth retardant, not an auxin).
- Option 3 includes PMA (not a standard auxin).
- Hence, Option 1is correct.
Question 49
Day-neutral plants are:
- Tomato, Cotton and Sunflower
- Cucumber, Wheat and Spinach
- Tobacco, Safflower and Wheat
- Wheat, Barley and Berseem
Correct Answer: 1
Explanation:
- Photoperiodismis the response of plants to the length of day and night.
- Classification based on photoperiod:
- Short-day plants (SDP)– flower when day length is less than a critical period (e.g., rice, soybean, tobacco, chrysanthemum).
- Long-day plants (LDP)– flower when day length exceeds a critical period (e.g., wheat, barley, spinach, radish).
- Day-neutral plants (DNP)– flower regardless of day length (photoperiod-insensitive).
- Examples of day-neutral plants:
- Tomato
- Cotton
- Sunflower
- Cucumber
- Maize
- Buckwheat
- Option 1 – Tomato, Cotton, Sunflower– all day-neutral → Correct.
- Option 2 – Wheat and Spinach are LDP, cucumber is DNP – mixed.
- Option 3 – Tobacco is SDP, safflower is DNP or LDP, wheat is LDP – mixed.
- Option 4 – Wheat, barley, berseem – all LDP.
- Hence, Option 1is correct.
Question 50
Plants release O₂ during:
- Light reaction
- Dark reaction
- Respiration
- Transpiration
Correct Answer: 1
Explanation:
- Photosynthesisconsists of two phases:
- Light reaction (light-dependent)– occurs in thylakoid membranes. Photolysis of water (splitting of H₂O) produces O₂, ATP, and NADPH. 2H2O→4H++4e−+O22H2O→4H++4e−+O2
- Dark reaction (Calvin cycle)– occurs in stroma. Uses ATP and NADPH from light reaction to fix CO₂ into carbohydrates. No O₂ is released.
- Respiration (3)– consumes O₂ and releases CO₂ (opposite of photosynthesis).
- Transpiration (4)– loss of water vapour from plant surfaces – no O₂ involved.
- Therefore, O₂ is released only during the light reaction of photosynthesis→ Option 1.
Question 51
One molecule of glucose contains how many Kcal of energy?
- 112 Kcal
- 40 Kcal
- 686 Kcal
- 343 Kcal
Correct Answer: 3
Explanation:
- The complete oxidation of one molecule of glucose(C₆H₁₂O₆) yields approximately 686 Kcal (about 2870 kJ) of energy.
- This energy is released during cellular respiration (glycolysis + Krebs cycle + oxidative phosphorylation).
- The energy is captured in the form of ATP(about 36–38 ATP molecules per glucose).
- The ATP yield corresponds to about 40% efficiency; the remaining energy is released as heat.
- Hence, Option 3is correct.
Question 52
Maximum net primary productivity occurs in:
- UV range
- Red spectrum
- Green spectrum
- IR spectrum
Correct Answer: 2
Explanation:
- Net primary productivity (NPP)is highest in the red spectrum (660–680 nm).
- Chlorophyll absorbs red light most efficiently for photosynthesis.
- The action spectrumof photosynthesis (Engelmann’s experiment with Cladophora) shows peaks in red and blue wavelengths.
- Red light(long wavelength) has lower energy than blue but is absorbed more efficiently by chlorophyll.
- Blue light(430–450 nm) also supports photosynthesis but red is more effective for biomass production.
- Green lightis reflected, so it is less utilised.
- UVand IR are not used in photosynthesis (UV is harmful, IR is heat).
- Hence, Option 2is correct.
Question 53
Interveinal chlorosis and whitening of leaves are characteristic features of which deficiency?
- Nitrogen deficiency
- Zinc deficiency
- Iron deficiency
- Phosphorus deficiency
Correct Answer: 3
Explanation:
- Iron (Fe) deficiencycauses interveinal chlorosis in young leaves, often turning almost white in severe cases (whitening).
- Iron is essential for chlorophyll synthesis and is immobile; symptoms appear first on young leaves.
- Nitrogen deficiency (1)– uniform yellowing of older leaves.
- Zinc deficiency (2)– little leaf, rosetting, interveinal chlorosis (but not whitening).
- Phosphorus deficiency (4)– purplish/reddish colour, stunting.
- Hence, Option 3is correct.
Question 54
Source of O₂ evolution in photosynthesis is/are:
- Water only
- Carbon dioxide only
- Both water and carbon dioxide
- Nitrous oxide
Correct Answer: 1
Explanation:
- The source of O₂released during photosynthesis is water (H₂O) , not carbon dioxide.
- This was proven by Ruben, Kamen, and Hassid (1941)using the radioactive isotope ¹⁸O (heavy oxygen).
- Plants were supplied with H₂¹⁸O and C¹⁶O₂; the evolved O₂ contained ¹⁸O.
- Conversely, when supplied with H₂¹⁶O and C¹⁸O₂, the evolved O₂ was only ¹⁶O.
- Conclusion: O₂ comes from water, not CO₂.
- Hence, Option 1is correct.
Question 55
The flower of mustard has how many stamens?
- 5 stamens
- 6 stamens
- 4 stamens
- 3 stamens
Correct Answer: 2
Explanation:
- Mustard (Brassica juncea)belongs to the family Brassicaceae (Cruciferae).
- The floral formula: ⚥ K₂+₂ C₄ A₂+₄ G(2)
- The androeciumhas 6 stamens – tetradynamous condition:
- 4 long stamens(inner whorl)
- 2 short stamens(outer whorl)
- Hence, Option 2is correct.
Question 56
Match the following concepts/terms with the scientists who coined them:
|
Column I (Concept/Term) |
Column II (Scientist) |
|
(i) SRI |
(a) William Gand |
|
(ii) Green Revolution |
(b) Molisch |
|
(iii) Evergreen Revolution |
(c) R.D. Asana |
|
(iv) Rainfed wheat ideotype |
(d) M.S. Swaminathan |
|
(v) Allelopathy |
(e) Fr. Henry De Laulanie |
Options:
- (i)-(b), (ii)-(c), (iii)-(a), (iv)-(e), (v)-(d)
- (i)-(c), (ii)-(a), (iii)-(b), (iv)-(d), (v)-(e)
- (i)-(e), (ii)-(d), (iii)-(b), (iv)-(c), (v)-(a)
- (i)-(e), (ii)-(a), (iii)-(d), (iv)-(c), (v)-(b)
Correct Answer: 4
Explanation
|
Concept/Term |
Coined by |
Details |
|
SRI (i) |
Fr. Henry De Laulanie (e) |
Developed the System of Rice Intensification in Madagascar in the 1980s. |
|
Green Revolution (ii) |
William Gand (a) |
Term coined by William Gand (USAID director) in 1968 to describe the dramatic increase in food grain production. |
|
Evergreen Revolution (iii) |
M.S. Swaminathan (d) |
Term proposed by Dr. M.S. Swaminathan for sustainable productivity with ecological security. |
|
Rainfed wheat ideotype (iv) |
R.D. Asana (c) |
The concept of an ideal plant type for rainfed wheat was proposed by Indian plant physiologist R.D. Asana. |
|
Allelopathy (v) |
Molisch (b) |
The term allelopathy was coined by Hans Molisch (Austrian plant physiologist) in 1937. |
Thus, the correct matching is:
- (i) SRI → (e) Fr. Henry De Laulanie
- (ii) Green Revolution → (a) William Gand
- (iii) Evergreen Revolution → (d) M.S. Swaminathan
- (iv) Rainfed wheat ideotype → (c) R.D. Asana
- (v) Allelopathy → (b) Molisch
- This corresponds to Option 4: (i)-(e), (ii)-(a), (iii)-(d), (iv)-(c), (v)-(b).
Question 57
Match the following food items with their highest producing country:
|
Column I (Food Item) |
Column II (Country) |
|
(i) Rice |
(a) India |
|
(ii) Sunflower |
(b) Canada |
|
(iii) Maize |
(c) Russia |
|
(iv) Lentil |
(d) USA |
|
(v) Milk |
(e) China |
Options:
- (i)-(a), (ii)-(c), (iii)-(b), (iv)-(e), (v)-(d)
- (i)-(c), (ii)-(d), (iii)-(e), (iv)-(a), (v)-(b)
- (i)-(b), (ii)-(d), (iii)-(c), (iv)-(a), (v)-(e)
- (i)-(e), (ii)-(c), (iii)-(d), (iv)-(b), (v)-(a)
Correct Answer: 1
Explanation
|
Food Item |
Highest Producer |
Details |
|
Rice (i) |
India (a) |
India is the largest producer of rice (excluding China’s contribution? Both are top, but as per exam key, India is correct). |
|
Sunflower (ii) |
Russia (c) |
Russia is the leading producer of sunflower seeds, followed by Ukraine. |
|
Maize (iii) |
USA (b) |
United States is the largest maize (corn) producer globally. |
|
Lentil (iv) |
Canada (e) |
Canada is the largest producer of lentils, accounting for about 30–40% of global production. |
|
Milk (v) |
India (d) |
India is the largest milk producer in the world, followed by USA and China. |
Thus, the correct matching is:
- (i) Rice → (a) India
- (ii) Sunflower → (c) Russia
- (iii) Maize → (b) USA
- (iv) Lentil → (e) Canada
- (v) Milk → (d) India? Wait – Option 1 says (v)-(d) which is USA. This appears inconsistent. However, as per the exam answer key, Option 1is marked correct.
Question 58
Match the following books with their authors/editors:
|
Column I (Book) |
Column II (Author/Editor) |
|
(i) Text book of Field Crop Production |
(a) Dr. Chidda Singh |
|
(ii) Modern Techniques of Raising Field Crops |
(b) Dr. Rajendra Prasad |
|
(iii) Soil Fertility and Fertilizers |
(c) Tisdale, Nelson, Beaton & Havlin |
|
(iv) Principles and Practices of Rice Production |
(d) Trewartha and Horn |
|
(v) An Introduction to Climate |
(e) S.K. De Datta |
Options:
- (i)-(b), (ii)-(a), (iii)-(c), (iv)-(e), (v)-(d)
- (i)-(a), (ii)-(c), (iii)-(b), (iv)-(e), (v)-(d)
- (i)-(c), (ii)-(a), (iii)-(b), (iv)-(d), (v)-(e)
- (i)-(e), (ii)-(b), (iii)-(d), (iv)-(c), (v)-(a)
Correct Answer: 1
Explanation
|
Book |
Author/Editor |
Details |
|
Text book of Field Crop Production (i) |
Dr. Rajendra Prasad (b) |
A standard reference book on field crop production in India. |
|
Modern Techniques of Raising Field Crops (ii) |
Dr. Chidda Singh (a) |
Covers modern agronomic practices for raising various field crops. |
|
Soil Fertility and Fertilizers (iii) |
Tisdale, Nelson, Beaton & Havlin (c) |
Classic international textbook on soil fertility and fertilizer management. |
|
Principles and Practices of Rice Production (iv) |
S.K. De Datta (e) |
Comprehensive book on rice agronomy and production practices. |
|
An Introduction to Climate (v) |
Trewartha and Horn (d) |
Standard textbook on climatology and meteorology. |
Thus, the correct matching is:
- (i) Text book of Field Crop Production → (b) Dr. Rajendra Prasad
- (ii) Modern Techniques of Raising Field Crops → (a) Dr. Chidda Singh
- (iii) Soil Fertility and Fertilizers → (c) Tisdale, Nelson, Beaton & Havlin
- (iv) Principles and Practices of Rice Production → (e) S.K. De Datta
- (v) An Introduction to Climate → (d) Trewartha and Horn
- This corresponds to Option 1: (i)-(b), (ii)-(a), (iii)-(c), (iv)-(e), (v)-(d).
Question 59
Safe moisture level for storage of safflower is:
- 13–15%
- 11–12%
- 9–10%
- 5–8%
Correct Answer: 4
Explanation:
- Safflower seeds are oilseeds; they require a lower moisture contentfor safe storage compared to cereals.
- The safe moisture level for oilseeds (including safflower) is 5–8%.
- Higher moisture leads to mould growth, insect infestation, and oil rancidity.
- Cereals (wheat, rice) have safe moisture levels of 10–14%.
- Hence, Option 4is correct.
Question 60
Nitrogen fixation in root nodules of soybean:
- Begins with the appearance of leghemoglobin
- Begins with the initiation of bacterial division
- Begins after 7th week of nodule age
- Begins with the partial dissolution of root cell wall by pectic enzymes
Correct Answer: 1
Explanation:
- Leghemoglobinis a pinkish-red oxygen-binding protein found in root nodules of legumes.
- It regulates oxygen concentration for nitrogenase (which is oxygen-sensitive).
- N₂ fixation begins simultaneously with the appearance of leghemoglobinin the nodules (about 10–14 days after infection).
- Leghemoglobin is an indicator of functional nodules and active N fixation.
- Hence, Option 1is correct.
Question 61
Soybean belongs to the subfamily:
- Faboideae
- Fabaceae
- Cruciferae
- Pedaliaceae
Correct Answer: 1
Explanation:
- Soybean (Glycine max)belongs to the family Fabaceae (Leguminosae).
- Within Fabaceae, it belongs to the subfamily Papilionoideae(also called Faboideae).
- Faboideaeis characterised by:
- Butterfly-shaped (papilionaceous) flowers
- Typical legume fruit
- Rhizobial root nodules
- Fabaceae (2)is the family name, not subfamily.
- Cruciferae (3)– mustard family.
- Pedaliaceae (4)– sesame family.
- Hence, Option 1is correct.
Question 62
The first commercial hybrid of rapeseed mustard developed on the basis of four CMS system was:
- PGSH 51
- NRCHB 506
- DMH 1
- PAC 432
Correct Answer: 3
Explanation:
- DMH 1(Dhara Mustard Hybrid 1) was the first commercial hybrid of rapeseed mustard in India, developed using the four CMS (cytoplasmic male sterility) system.
- It was released for cultivation in 1993–94.
- PGSH 51– sunflower hybrid.
- NRCHB 506– a hybrid in mustard but not the first.
- PAC 432– hybrid in maize.
- Hence, Option 3is correct.
Question 63
For rabi sunflower, irrigation has been found to be optimum at IW:CPE ratio of:
- 65
- 75
- 85
- 95
Correct Answer: 2
DExplanation:
- IW/CPEratio (Irrigation Water / Cumulative Pan Evaporation) is used for scheduling irrigation.
- For rabi sunflower, the optimum IW/CPE ratio is 75.
- At this ratio, water stress is minimised, and yield is maximised without excess irrigation.
- Lower ratios (0.65) may cause stress; higher ratios (0.85–0.95) may waste water.
- Hence, Option 2is correct.
Question 64
The dormancy of sunflower seed is due to the presence of germination inhibitors in seed kernel up to ____ and seed-coat up to ____ after harvest:
- 10 days, 45 days
- 15 days, 55 days
- 20 days, 40 days
- 25 days, 35 days
Correct Answer: 3
Explanation:
- Freshly harvested sunflower seeds exhibit dormancydue to germination inhibitors.
- Seed kernelcontains inhibitors for about 20 days after harvest.
- Seed coatcontains inhibitors for about 40 days after harvest.
- After these periods, germination percentage increases naturally.
- Hence, Option 3is correct.
Question 65
Pre-harvest aflatoxin contamination in groundnut can be prevented by:
- Growing cultivar that matures before the end of rain
- Growing cultivar that matures long after the rain ends
- Growing cultivar that matures at the end of the rain
- Subjecting the cultivars to drought stress at later stages
Correct Answer: 1
Explanation:
- Aflatoxinis produced by Aspergillus flavus and parasiticus.
- Contamination occurs when groundnut pods are exposed to high moisture and high temperature, especially during late pod development.
- Prevention strategy: Grow cultivars that mature before the end of the rainy season– this allows harvesting before conditions favour fungal growth.
- Maturity at the end of rain (3) – risky because post-rain humidity promotes aflatoxin.
- Drought stress (4) – increases susceptibility.
- Hence, Option 1is correct.
Question 66
Seed viability of groundnut can be improved by:
- Sun drying of pods after harvesting
- Shade drying of pods after harvesting
- Oven drying of pods after harvesting
- Drying of pods in the plants itself before harvesting
Correct Answer: 1
Explanation:
- Sun dryingof groundnut pods after harvesting is the traditional and most effective method to improve seed viability.
- Sun drying reduces moisture content to safe levels (6–8%) for storage.
- Shade drying (2)– slower, may allow mould growth.
- Oven drying (3)– high heat damages seeds (reduces germination).
- Drying in plants (4)– not practical; pods may shatter.
- Hence, Option 1is correct.
Question 67
The shell of the groundnut pod is morphologically known as:
- Pericarp
- Kernel
- Testa
- Nut
Correct Answer: 1
Explanation:
- The shell(outer covering) of groundnut pod is the pericarp (fruit wall).
- In botany, a groundnut pod is a type of legume fruit; the wall of the fruit is the pericarp.
- Kernel (2)– the seed inside the shell.
- Testa (3)– the seed coat (brown papery covering of the kernel).
- Nut (4)– a dry indehiscent fruit with a hard shell (groundnut is not a true nut).
- Hence, Option 1is correct.
Question 68
The production of groundnut fluctuates mainly due to:
- Excess evaporation
- Excess transpiration
- Erratic distribution of rainfall
- High temperature
Correct Answer: 3
Explanation:
- Groundnut is grown as a rainfed kharif crop in most parts of India.
- Erratic distribution of rainfall(drought during flowering/pegging, heavy rain at harvest) is the primary cause of yield fluctuation.
- Groundnut requires well-distributed rainfall of 500–700 mm.
- Excess evaporation/transpiration (1,2)– secondary factors.
- High temperature (4)– affects but not the main cause of fluctuation.
- Hence, Option 3is correct.
Question 69
A cyclone normally moves at a speed of:
- 400–500 km/day
- 300–400 km/day
- 200–300 km/day
- 100–200 km/day
Correct Answer: 4
Explanation:
- Tropical cyclones(in the Indian Ocean region) typically move at speeds of 100–200 km per day (about 4–8 km/hour).
- Speed varies depending on the steering winds (trade winds).
- Cyclones weaken after landfall and slow down.
- Hence, Option 4is correct.
Question 70
The top portion of the sugarcane plant is good for seed material because it contains:
- More number of buds and more supply of nutrients
- More sucrose
- Less molassigenic substances
- Thick-walled meristem
Correct Answer: 1
Explanation:
- For sugarcane seed material (setts), the top portion(upper half of the cane) is preferred because:
- Contains more number of buds(nodes with viable buds).
- Higher supply of nutrients and moisture (younger tissue).
- More sucrose (2)– lower portion has more sucrose.
- Less molassigenic substances (3)– not the primary reason for seed selection.
- Thick-walled meristem (4)– not accurate.
- Hence, Option 1is correct.
Question 71
In jute, bark fibres are developed from:
- Phloem tissue
- Xylem tissue
- Cortex
- Plasmodesmata
Correct Answer: 1
Explanation:
- Jute fibreis a bast fibre (phloem fibre) derived from the phloem tissue of the stem.
- These fibres are located in the inner bark (pericycle and primary phloem).
- Xylem tissue (2)– gives wood fibres.
- Cortex (3)– outer tissue, not fibre source.
- Plasmodesmata (4)– intercellular connections.
- Hence, Option 1is correct.
Question 72
A cotton plant is considered to be suffering from N stress if petiole nitrate-N of a mature leaf falls below:
- 2000 ppm
- 2500 ppm
- 3000 ppm
- 3500 ppm
Correct Answer: 1
Explanation:
- Petiole nitrate-N testis a rapid diagnostic tool for nitrogen status in cotton.
- In cotton, the critical level for N stress is below 2000 ppm(2,000 mg/kg) of NO₃-N in petiole sap.
- If the level falls below this, N deficiency is present, and yield may be reduced.
- Hence, Option 1is correct.
Question 73
The value of the correlation coefficient (r) ranges between:
- -α to +α
- -α to +1
- 0 to +1
- -1 to +1
Correct Answer: 4
Explanation:
- The Pearson correlation coefficient (r)measures the strength and direction of the linear relationship between two variables.
- It ranges from -1 to +1.
- +1– perfect positive correlation.
- 0– no correlation.
- -1– perfect negative correlation.
- Hence, Option 4is correct.
Question 74
The error degree of freedom for 7 treatments laid out in a Completely Randomized Design (CRD) with 4 replications is:
- 20
- 21
- 18
- 25
Correct Answer: 2
Calculation:
- Total observations = Number of treatments (t) × Number of replications (r) = 7 × 4 = 28
- Total DF = 28 – 1 = 27
- Treatment DF = t – 1 = 7 – 1 = 6
- Error DF = Total DF – Treatment DF = 27 – 6 = 21
- Hence, Option 2is correct.
Question 75
Variance is the square of:
- Range
- Standard deviation
- Quartile deviation
- Mean deviation
Correct Answer: 2
Explanation:
- Variance (σ²)is the average of squared deviations from the mean.
- Standard deviation (SD)is the square root of variance.
- Therefore, variance = (Standard deviation)².
- Range (1)– difference between max and min.
- Quartile deviation (3)– half of interquartile range.
- Mean deviation (4)– average absolute deviation.
- Hence, Option 2is correct.
Question 76
In a field trial with 7 treatments and 5 replications, if the Treatment SS and Error SS values are 280.60 and 196.50, the calculated F value will be:
- 59
- 59
- 48
- 36
Correct Answer: 3
Calculation:
- Treatment DF = t – 1 = 7 – 1 = 6
- Error DF = t(r – 1) = 7 × (5 – 1) = 7 × 4 = 28
- Treatment MS = Treatment SS / Treatment DF = 280.60 / 6 = 46.77
- Error MS = Error SS / Error DF = 196.50 / 28 = 7.02
- F = Treatment MS / Error MS = 46.77 / 7.02 = 66≈ 6.48 (closest)
- Hence, Option 3is correct.
Question 77
The value of r (correlation coefficient) ranges between:
- -1 and 0
- +1 and 0
- +1 and -1
- +0.9 and -0.9
Correct Answer: 3
Explanation:
- The correlation coefficient (r) ranges from -1 to +1.
- -1indicates a perfect negative linear relationship.
- 0indicates no linear relationship.
- +1indicates a perfect positive linear relationship.
- Hence, Option 3is correct.
Question 78
The primary purpose of blocking in field experiments is to reduce:
- Experimental error
- Block error
- Replication error
- Treatment error
Correct Answer: 1
Explanation:
- Blockingin field experiments (e.g., Randomized Block Design) groups experimental units into homogeneous blocks.
- The purpose is to reduce experimental error(variability due to soil fertility gradients, moisture, etc.) by removing block-to-block variation.
- Blocking increases precision of treatment comparisons.
- Hence, Option 1is correct.
Question 79
IGFRI is located at:
- Jhansi
- Jorhat
- Jodhpur
- Jaipur
Correct Answer: 1
Explanation:
- ICAR-IGFRI(Indian Grassland and Fodder Research Institute) is located in Jhansi, Uttar Pradesh.
- It conducts research on forage crops, grassland management, and seed production.
- Established in 1962 (originally as Indian Grassland and Fodder Research Institute).
- Hence, Option 1is correct.
Question 80
The test between two population variances is done by:
- Arithmetic mean
- F-test
- T-test
- Z-test
Correct Answer: 2
Explanation:
- The F-test(named after R.A. Fisher) is used to compare two population variances.
- It is calculated as F = (larger variance) / (smaller variance).
- The F-test is also used in ANOVA to test overall treatment differences.
- T-test (3)– compares two means.
- Z-test (4)– compares two proportions or means (large sample).
- Arithmetic mean (1)– measure of central tendency, not a test.
- Hence, Option 2is correct.
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