Cotton Crop Special -2 — Agri Master Mind

Uniformity Ratio (UR) in cotton fiber testing is a measure of:
  • The proportion of short fibers.
  • The average length of the fibers.
  • The ratio of mean length to upper half mean length, indicating length consistency.
  • The strength consistency along the fiber length.
Explanation: Uniformity Ratio indicates the consistency of fiber length within a sample. A higher UR means the fibers are more uniform in length, which is desirable for spinning.
Which cultural practice helps reduce the incidence of early-season sucking pests like jassids and thrips in cotton?
  • Late sowing of the crop.
  • Timely sowing and maintaining good crop vigor.
  • Increasing plant density significantly.
  • Applying high doses of Nitrogen.
Explanation: Healthy, vigorous plants due to timely sowing, proper nutrition, and irrigation are generally more tolerant to pest feeding compared to stressed plants. Early sowing can also sometimes help escape peak pest periods depending on the region.
The main function of sympodial branches in a cotton plant is:
  • To support the main stem.
  • To produce flowers and bolls.
  • To absorb water and nutrients.
  • To provide vegetative cover.
Explanation: Sympodial branches grow horizontally or diagonally from the main stem and monopodial branches and are where the squares, flowers, and subsequently the bolls develop.
What is the typical growth habit of the widely cultivated Gossypium hirsutum (Upland cotton)?
  • Perennial shrub
  • Annual herbaceous plant
  • Deciduous tree
  • Aquatic plant
Explanation: Although botanically a perennial shrub, Gossypium hirsutum is cultivated as an annual crop, completing its life cycle from seed to harvest within one growing season.
Which primary nutrient is most mobile in the soil and prone to leaching, especially in sandy soils with high rainfall or irrigation?
  • Phosphorus (P)
  • Potassium (K)
  • Nitrogen (N) - particularly nitrate form
  • Calcium (Ca)
Explanation: Nitrogen, especially in the highly available nitrate (NO₃⁻) form, is negatively charged and not adsorbed onto soil particles (which are also generally negatively charged). This makes it highly susceptible to movement with water through the soil profile (leaching).
The process of removing unwanted plant parts like lower leaves or excess branches to improve air circulation and sunlight penetration is called:
  • Topping
  • Pruning (or bottom pruning)
  • Defoliation
  • Earthing up
Explanation: Pruning, specifically bottom pruning, involves removing non-fruiting lower branches to improve air flow, reduce humidity within the canopy (helping manage diseases), and make pest control and irrigation easier. Topping removes the terminal bud, and defoliation removes leaves before harvest.
Which implement is commonly used for secondary tillage to prepare a fine seedbed in cotton cultivation?
  • Mouldboard plough
  • Disc plough
  • Cultivator or Harrow
  • Ridge plough
Explanation: Cultivators, harrows (disc harrow, tine harrow), and rotavators are secondary tillage implements used after initial plowing to break down clods, level the field, and create a fine, firm seedbed suitable for sowing small seeds like cotton.
Plant Protection Code (PPC) guidelines in cotton cultivation mainly pertain to:
  • Irrigation scheduling.
  • Safe and judicious use of pesticides.
  • Fertilizer application rates.
  • Selection of cotton varieties.
Explanation: Plant Protection Code guidelines, often part of Good Agricultural Practices (GAP) or specific programs like the one related to cotton quality (e.g., residue standards), focus on the responsible use of pesticides to minimize residues in lint and protect the environment and human health.
The term "Trash" in cotton quality refers to:
  • Unwanted fiber pieces.
  • Cotton seeds mixed with lint.
  • Low-quality lint.
  • Foreign matter like leaves, bracts, stems, sand, etc., mixed with the lint.
Explanation: Trash includes any non-lint material present in the harvested seed cotton or ginned lint, which reduces the quality and market value.
What is the most effective method for managing Cotton Leaf Curl Virus Disease (CLCuD)?
  • Applying fungicides to the soil.
  • Applying specific insecticides to kill the virus.
  • Providing excess irrigation.
  • Controlling the vector (whitefly) and planting resistant varieties.
Explanation: CLCuD is a viral disease transmitted by the whitefly vector. There is no cure for viral diseases in plants. Management relies on controlling the whitefly population and, most importantly, planting resistant or tolerant cotton varieties.
Which nutrient is critical for chlorophyll formation and can cause interveinal chlorosis (yellowing between veins) on younger leaves if deficient?
  • Nitrogen (N)
  • Phosphorus (P)
  • Potassium (K)
  • Iron (Fe)
Explanation: Iron is a component of enzymes involved in chlorophyll synthesis. Its deficiency leads to a classic symptom of interveinal chlorosis, starting on the young, upper leaves because iron is relatively immobile in the plant.
The process of applying fertilizers in split doses rather than a single application is primarily aimed at:
  • Providing nutrients to the crop when they are most needed and minimizing losses (leaching, volatilization).
  • Reducing the total amount of fertilizer needed.
  • Increasing weed growth.
  • Making fertilizer application easier.
Explanation: Splitting fertilizer application (especially Nitrogen) ensures a continuous supply of nutrients during the critical growth stages of the crop, improves nutrient use efficiency, and reduces losses through leaching or volatilization.
What is the major disadvantage of continuous monocropping of cotton?
  • Depletion of specific soil nutrients.
  • Reduced incidence of pests and diseases.
  • Improved soil structure.
  • Higher marketing price for the produce.
Explanation: Continuous cultivation of the same crop can lead to the build-up of specific pests, diseases, and weeds associated with that crop, as well as the depletion of particular nutrients, and can degrade soil health.
The term "BT cotton refuge" refers to:
  • An area where Bt cotton is not planted.
  • An area treated with extra insecticides.
  • A storage area for Bt cotton seeds.
  • An area planted with non-Bt cotton within or adjacent to a Bt cotton field.
Explanation: Refuges (areas planted with non-Bt cotton) are mandatory in Bt cotton cultivation. They are crucial for managing pest resistance to the Bt toxin by providing a population of susceptible insects that can mate with any resistant insects emerging from the Bt field, thus diluting resistance genes.
Which cotton variety characteristic is most important for suitability for mechanical harvesting?
  • High fiber strength.
  • Short staple length.
  • High seed index.
  • Determinant growth habit and uniform boll maturity.
Explanation: Mechanical harvesting is most efficient when a large proportion of bolls open at the same time. Varieties with a more determinant growth habit and uniform boll maturity are preferred for mechanical picking or stripping.
The role of Calcium (Ca) in cotton is important for:
  • Energy transfer.
  • Cell wall structure and plant strength.
  • Chlorophyll synthesis.
  • Root nodule formation.
Explanation: Calcium is a structural component of cell walls, providing rigidity and strength to plant tissues. It is essential for cell division and elongation and plays a role in fruit (boll) development.
The primary benefit of early-season pest monitoring (scouting) in cotton fields is to:
  • Determine the exact yield potential.
  • Identify pest presence early and make timely management decisions based on economic threshold levels.
  • Estimate the total amount of pesticide needed for the season.
  • Assess the plant's nutrient status.
Explanation: Regular pest monitoring allows farmers to detect pest infestations before they cause significant damage, identify the pest species, assess their population density, and decide whether control measures are necessary based on established economic thresholds (the pest level at which control measures become economically viable).
When practicing ridge and furrow method for irrigation in cotton, the crop is generally planted:
  • On the ridges.
  • In the furrows.
  • On the side of the ridges, above the water level in the furrow.
  • Randomly across the field.
Explanation: In ridge and furrow irrigation, cotton is typically planted on the side of the ridge, slightly above where the water level is maintained in the furrow. This allows water to seep laterally to the roots while keeping the root crown out of direct contact with standing water, preventing waterlogging.
Which term describes the weight of 100 seeds of cotton?
  • Test weight
  • Seed index
  • Thousand grain weight
  • Seed rate
Explanation: Seed index is the weight of 100 seeds, often used to estimate seed size and calculate appropriate seed rates. Thousand grain weight (or thousand seed weight) is more commonly used for cereals and pulses.
Blackening and rotting of roots and lower stem of young cotton seedlings is a common symptom of:
  • Rust
  • Powdery Mildew
  • Damping-off
  • Leaf Rust
Explanation: Damping-off is a common disease of seedlings caused by soil-borne fungi (like Pythium, Rhizoctonia) that causes the seedlings to rot at the soil line and collapse.
What is the role of Potassium Permanganate in cotton fiber testing?
  • It is used in tests for assessing fiber maturity (e.g., Causticaire method).
  • It measures fiber strength.
  • It measures fiber length.
  • It measures trash content.
Explanation: While not the primary modern method (HVI uses airflow for micronaire), Potassium Permanganate staining is a classical method used to assess the degree of secondary wall development (maturity) in cotton fibers based on how the stain is absorbed.
The "Economic Threshold Level" (ETL) in pest management is the pest population density at which:
  • The pest causes irreversible damage.
  • The cost of control equals the value of damage prevented.
  • The pest population is highest.
  • Control measures should be applied to prevent the pest population from reaching the Economic Injury Level (EIL).
Explanation: ETL is a proactive threshold. It's the level where action is needed to prevent the pest population from reaching the Economic Injury Level (EIL), which is the level where the cost of pest control equals the value of the damage caused by the pest.
Which type of herbicide is applied directly to the foliage of emerged weeds?
  • Pre-emergence herbicide
  • Post-emergence herbicide
  • Soil applied herbicide
  • Pre-plant incorporated herbicide
Explanation: Post-emergence herbicides are designed to be sprayed onto weeds that have already emerged and are actively growing.
In rainfed cotton cultivation, tied ridging or making conservation furrows helps in:
  • Promoting waterlogging.
  • Improving drainage.
  • Conserving soil moisture by impounding rainfall.
  • Increasing fertilizer runoff.
Explanation: Tied ridging or creating cross-ties in furrows creates small basins that capture and hold rainfall, preventing runoff and allowing more water to infiltrate the soil, which is crucial for moisture conservation in rainfed areas.
Gummy stem blight and boll rot in cotton can be caused by which type of pathogen?
  • Virus
  • Bacteria
  • Fungus
  • Nematode
Explanation: Various fungi (e.g., Colletotrichum, Rhizoctonia, Fusarium) are responsible for diseases causing stem blight and boll rots in cotton.
What is the primary benefit of growing trap crops in cotton fields?
  • They repel pests away from the main cotton crop.
  • They attract pests away from the cotton crop, concentrating them for easier management or destruction.
  • They fix nitrogen for the cotton crop.
  • They improve soil drainage.
Explanation: Trap crops are planted to be more attractive to certain pests than the main crop (cotton). Pests accumulate on the trap crop and can then be easily controlled, reducing pest pressure on the cotton. Example: Marigold for Helicoverpa bollworm.
The term "Verticillium Wilt" in cotton refers to a disease caused by:
  • A virus transmitted by whiteflies.
  • A bacterium causing angular leaf spot.
  • A soil-borne fungus causing wilting and vascular discoloration.
  • A nematode affecting roots.
Explanation: Verticillium wilt, like Fusarium wilt, is caused by a soil-borne fungus (Verticillium dahliae) that infects the vascular system, leading to wilting, leaf yellowing, and internal stem discoloration.
What is the main factor determining the optimal timing for the first irrigation in cotton?
  • Calendar date.
  • Stage of crop growth and soil moisture status.
  • Availability of irrigation water.
  • Presence of pests.
Explanation: Irrigation scheduling should be based on the crop's water needs at different growth stages (phenology) and the actual moisture level available in the soil profile, often assessed through soil moisture sensors or the feel method.
Cotton seed treatment with insecticides is primarily done to protect the seedlings from:
  • Bollworms.
  • Mites.
  • Mealybugs.
  • Early-season sucking pests (jassids, thrips, aphids) and soil pests.
Explanation: Seed treatment with systemic insecticides provides protection to young seedlings against sap-sucking insects and some soil-borne pests during the vulnerable initial growth phase.
Which organization in India is primarily responsible for cotton research and development?
  • Indian Council of Agricultural Research (ICAR) - specifically ICAR-CICR.
  • Cotton Corporation of India (CCI).
  • National Agricultural Cooperative Marketing Federation of India Ltd. (NAFED).
  • Food Corporation of India (FCI).
Explanation: ICAR (Indian Council of Agricultural Research), through its dedicated institute, the Central Institute for Cotton Research (CICR), is the nodal body for cotton research and development in India. CCI is involved in marketing and procurement.
The ratio of lint weight to seed cotton weight, expressed as a percentage, is called:
  • Staple length
  • Ginning outturn (GOT)
  • Trash content
  • Moisture content
Explanation: Ginning Outturn (GOT) is the percentage of lint obtained from a given weight of seed cotton after ginning. It's a measure of the efficiency of separating lint from seed.
Ratooning (allowing the cotton crop to grow back after the first harvest) is generally NOT recommended in cotton because:
  • It reduces fertilizer efficiency.
  • It delays maturity of the subsequent crop.
  • It leads to the build-up of pests (especially Pink Bollworm) and diseases.
  • It requires more water.
Explanation: Ratooning allows pests and diseases, particularly the Pink Bollworm which overwinters in plant residues, to carry over to the next season, leading to severe infestations and making control difficult. It also often results in lower yield and quality in the subsequent pickings compared to a fresh planting.
What does the term "Gossypol" refer to in cotton?
  • A type of fiber.
  • A specific type of fertilizer.
  • A cotton disease.
  • A natural pigment and toxic compound found in cotton seeds and glands.
Explanation: Gossypol is a polyphenolic aldehyde present in pigment glands of cotton plants, particularly in the seeds. It acts as a natural defense against pests and diseases but is toxic to non-ruminant animals, limiting the use of cotton seed meal in their feed unless detoxified.
The symptom 'Red Leaf' in cotton is often associated with:
  • Iron deficiency.
  • Excess Nitrogen.
  • Boron toxicity.
  • Potassium deficiency or water stress (especially in Bt hybrids).
Explanation: Reddening of cotton leaves (Red Leaf) can be caused by several factors, including phosphorus deficiency, but it is most commonly associated with potassium deficiency, water stress, or genetic factors, particularly noticeable in some Bt hybrids in later stages.
The recommended depth of sowing for cotton seeds is typically:
  • 0-1 cm (very shallow)
  • 2-5 cm (shallow to medium)
  • 10-15 cm (deep)
  • On the soil surface
Explanation: Cotton seeds should be sown at a depth of 2-5 cm, depending on soil moisture and texture. Shallow planting in moist soil ensures quick emergence, while slightly deeper planting might be needed in drier conditions.
Which irrigation method is best suited for saline soils in cotton?
  • Flood irrigation (can worsen salinity)
  • Sprinkler irrigation (can cause leaf burn with saline water)
  • Drip irrigation (localizes water, minimizes surface evaporation and salt accumulation in the root zone)
  • Furrow irrigation (can lead to salt build-up on ridges)
Explanation: Drip irrigation is advantageous in saline soils because it maintains a relatively high moisture content in the wetted zone, pushing salts to the periphery of the wetted area and away from the root zone, minimizing salt stress on the plants.
The use of pheromone traps in cotton pest management is primarily for:
  • Killing all pests in the field.
  • Attracting beneficial insects.
  • Monitoring pest populations (especially moths) to aid in decision making.
  • Direct control of sucking pests.
Explanation: Pheromone traps release synthetic sex pheromones to attract specific male insect pests (like bollworm moths). They are used for monitoring pest activity, determining the timing of pest emergence, and assessing population levels to guide the timing of control measures.
Which type of cotton provides the longest and finest fibers, suitable for producing high-quality textiles?
  • Gossypium arboreum
  • Gossypium herbaceum
  • Gossypium hirsutum
  • Gossypium barbadense (Egyptian/Pima cotton)
Explanation: Gossypium barbadense is known for producing extra-long staple (ELS) cotton, which is exceptionally long, strong, and fine, used for premium textiles. G. hirsutum is medium to long staple.
Soil organic carbon content is a key indicator of soil health. Applying which input is most effective in increasing soil organic carbon in cotton fields?
  • Di-ammonium Phosphate (DAP)
  • Muriate of Potash (MOP)
  • Farm Yard Manure (FYM) or compost
  • Urea
Explanation: Organic manures like FYM, compost, or crop residues directly add organic matter to the soil, which decomposes over time to form stable soil organic carbon, improving soil health and fertility.
The term "stickiness" in cotton lint is usually caused by:
  • Excess moisture during storage.
  • Presence of honeydew excreted by sucking pests like whiteflies and aphids.
  • High fiber strength.
  • Low micronaire value.
Explanation: Stickiness is a serious cotton quality defect caused by sugars present in the honeydew secreted by sucking insects, particularly whiteflies and aphids. This makes processing difficult in textile mills.
What is the primary mode of action of glyphosate, a widely used herbicide (especially with tolerant cotton varieties)?
  • Inhibits photosynthesis.
  • Inhibits amino acid synthesis.
  • Disrupts cell wall formation.
  • Causes uncontrolled cell division.
Explanation: Glyphosate inhibits the enzyme EPSP synthase, which is involved in the synthesis of essential aromatic amino acids (phenylalanine, tyrosine, and tryptophan) in plants, leading to plant death.
Delinting of cotton seeds (removing fuzz from seeds) is done to:
  • Reduce seed weight.
  • Improve seed germination and facilitate mechanical sowing.
  • Increase pest resistance.
  • Enhance fiber strength.
Explanation: Delinting (using acid or mechanical methods) removes the short fuzz fibers attached to the seed, allowing for easier and more precise mechanical sowing and improving water absorption for quicker and more uniform germination.
The recommended plant population density for hybrid cotton varieties is generally:
  • Much higher than conventional varieties.
  • Dependent only on soil type, not variety type.
  • Much lower than conventional varieties.
  • Similar to conventional varieties.
Explanation: Hybrid cotton varieties are generally more vigorous and require wider spacing to express their full potential for branching and boll production. Therefore, they are planted at lower plant densities compared to less vigorous conventional or desi varieties.
Sulphur (S) is an important secondary nutrient for cotton, primarily involved in:
  • Root elongation.
  • Boll setting percentage.
  • Protein synthesis and chlorophyll formation.
  • Water uptake.
Explanation: Sulphur is a constituent of amino acids (like cysteine, methionine) and proteins, and is also involved in chlorophyll formation. Its deficiency can affect protein synthesis and lead to general yellowing of leaves (similar to N deficiency, but often affecting younger leaves first).
The practice of intercropping short-duration crops like onion or groundnut on the ridges between cotton rows in broad-bed furrow system is known as:
  • Sole cropping.
  • Relay cropping.
  • Sequence cropping.
  • Companion cropping / Intercropping.
Explanation: This is a form of intercropping or companion cropping where different crops are grown simultaneously in the same field, leveraging different spatial or temporal niches.
What is the primary role of plant growth regulators (PGRs) sometimes used in cotton?
  • To kill insect pests.
  • To provide nutrients to the plant.
  • To modify plant growth and development, such as controlling height or promoting boll retention.
  • To improve soil structure.
Explanation: PGRs are chemicals that, at low concentrations, influence plant physiological processes. In cotton, they are sometimes used to manage excessive vegetative growth (e.g., mepiquat chloride), promote boll retention, or aid in defoliation.
The critical period for weed competition in cotton is generally during:
  • Seedling to vegetative growth (first 6-8 weeks).
  • Flowering to boll development.
  • Boll maturity.
  • Pre-sowing stage.
Explanation: Weeds compete most severely with cotton for light, water, and nutrients during the early growth stages (seedling and vegetative phase), impacting plant establishment and vigor. Effective weed control during the first 6-8 weeks is crucial for minimizing yield losses.
The percentage of light reflectance from a cotton field can be used to estimate:
  • Soil pH.
  • Plant vigor and health (e.g., using NDVI).
  • Pest population density.
  • Fiber length.
Explanation: Remote sensing techniques, such as using normalized difference vegetation index (NDVI) based on near-infrared and red light reflectance, can provide information on the 'greenness' or photosynthetic activity of the crop canopy, which correlates with plant vigor, health, and biomass.
Good quality cotton lint should have moisture content within a specific range. What is the generally recommended moisture content range for safe storage and processing?
  • Below 4%
  • 6% to 8%
  • 10% to 12%
  • Above 15%
Explanation: A moisture content of around 6% to 8% is considered ideal for cotton lint. Higher moisture can lead to microbial spoilage, heating, discoloration, and processing problems, while excessively low moisture can increase static electricity and fiber breakage.
A severe infestation of spider mites in cotton typically causes:
  • Wilting of the entire plant.
  • Angular black spots on leaves.
  • Silvery speckling or bronzing of leaves, often with fine webbing on the underside.
  • Galls on the roots.
Explanation: Spider mites are tiny arachnids that suck sap from leaves, causing stippling (silvery or yellow speckles), which can coalesce into bronzing. Heavy infestations often result in characteristic fine webbing, particularly on the undersides of leaves.