Maharashtra HSC Bifocal Horticulture (B5) cheat sheet

Horticulture = cultivation of garden crops; divided into olericulture (vegetables), pomology (fruits), floriculture (flowers) and landscaping.

Photosynthesis: 6CO2 + 6H2O + light → C6H12O6 + 6O2; occurs in chloroplasts, light reactions in thylakoids, Calvin cycle in stroma.

C3 plants fix CO2 via RuBisCO into 3-phosphoglycerate; C4 plants use PEP carboxylase with a 4-carbon acid intermediate; CAM plants fix CO2 at night.

Transpiration pull (cohesion-tension theory) drives water ascent through xylem; stomatal opening is driven by K+ influx into guard cells.

Auxin (IAA) promotes apical dominance and rooting; gibberellin promotes stem elongation and seed germination; cytokinin promotes cell division; ethylene ripens fruit; ABA closes stomata.

Photoperiodism: short-day plants flower when night exceeds a critical length; long-day plants flower when night is shorter; day-neutral plants are insensitive.

Vernalization is low-temperature promotion of flowering (e.g., wheat, cabbage); stratification is cold-moist seed treatment to break dormancy.

Crop growth rate = (W2 − W1)/(t2 − t1) per unit ground area; relative growth rate = (ln W2 − ln W1)/(t2 − t1).

Soil texture triangle classifies sand, silt and clay; loam is a balanced mixture and is generally the most productive texture.

Soil pH scale 0–14; most horticultural crops perform best at pH 6.0–7.0; pH below 5.5 increases Al and Mn toxicity.

Cation exchange capacity (CEC) is measured in cmol(+)/kg or meq/100 g; clay and organic matter raise CEC, sandy soils have low CEC.

Base saturation = (sum of exchangeable bases / CEC) × 100; higher base saturation generally indicates higher fertility.

Bulk density = oven-dry soil mass / total volume; ideal mineral soils are 1.1–1.6 g/cm3; porosity = 1 − (bulk density / particle density).

Field capacity is water retained after free drainage; permanent wilting point is where plants cannot extract water; available water = FC − PWP.

Soil erosion control: contour bunding, terracing, strip cropping, mulching and check dams reduce runoff velocity and sediment loss.

Saline soils have high EC and high ESP < 15; sodic soils have ESP > 15 and pH > 8.5; gypsum is used to reclaim sodic soils.

Fertilizer grade N-P2O5-K2O expresses nutrient percentage; urea is 46-0-0, DAP is 18-46-0, MOP is 0-0-60, SSP is 0-16-0.

Farmyard manure (FYM) is bulky organic manure; well-rotted FYM supplies about 0.5% N, 0.2% P2O5 and 0.5% K2O.

Green manure crops (e.g., sunhemp, dhaincha) are grown and ploughed in situ to add organic matter and nitrogen.

Composting: C:N ratio near 25–30:1 is optimum; turning the heap supplies oxygen; thermophilic phase reaches 55–65 °C.

Vermicompost is produced by earthworms; it is rich in humus, plant growth hormones and beneficial microbes.

Biofertilizers: Rhizobium for legumes, Azotobacter free-living, Azospirillum for cereals, phosphate-solubilizing bacteria release P from insoluble forms.

Nitrogen is mobile in soil (leaching, volatilization, denitrification); phosphorus and potassium are relatively immobile and should be placed near the root zone.

Fertigation delivers soluble fertilizers through drip irrigation, improving nutrient-use efficiency and reducing leaching losses.

Vegetable crops are grouped by edible part: root (carrot, radish), tuber (potato), leafy (spinach), fruit (tomato, brinjal), flower (cauliflower).

Nursery raising: seed rate for tomato is about 300–400 g/ha; seedlings are transplanted at 4–5 true leaf stage.

Tomato fruit set is poor above 32 °C or below 15 °C; fruit cracking is linked to irregular water supply and calcium deficiency.

Brinjal (eggplant) belongs to Solanaceae; fruit and shoot borer (Leucinodes orbonalis) is the key pest, managed by pheromone traps and shoot clipping.

Cauliflower curd initiation requires low temperature; early varieties are more heat-tolerant; buttoning is premature curd formation due to cold stress.

Onion bulb formation depends on photoperiod and temperature; short-day varieties are grown in the plains and long-day varieties in the hills.

Potato seed rate is about 2.0–2.5 t/ha of tubers; earthing up protects tubers from greening and potato tuber moth.

Vegetable crop rotation with non-host crops reduces soil-borne pathogens and nematodes; avoid repeating Solanaceae in the same plot.

Fruit types: pome (apple, pear), drupe (mango, peach), berry (grape, banana), hesperidium (citrus), aggregate (strawberry).

Mango (Mangifera indica) is Anacardiaceae; flowering is induced by cool dry weather; the 'off-year' (alternate bearing) problem is managed by pruning and paclobutrazol.

Grape pruning: forward pruning in winter removes 60–90% of growth; back pruning in summer; gibberellic acid increases berry size.

Banana is a giant herb; suckers are the planting material; de-suckering and propping are essential management practices.

Citrus decline is associated with tristeza virus, Phytophthora root rot and micronutrient deficiency; use of tolerant rootstocks reduces losses.

Fruit drop is controlled by auxin sprays (NAA at low concentration) and by maintaining uniform soil moisture.

Hi-tech horticulture uses micropropagation, high-density planting, drip fertigation and protected cultivation to raise productivity.

Orchard layout systems: square, rectangular, quincunx, hexagonal and contour planting; plant population per hectare depends on spacing.

Rose, chrysanthemum, carnation, gladiolus and marigold are major cut-flower crops; loose flowers include marigold, jasmine and crossandra.

Pinching removes the growing tip to encourage branching; disbudding removes side buds to improve flower size; deblossoming removes flowers to strengthen the plant.

Chrysanthemum is a short-day plant; flowering is manipulated by blackout (short day) or night-break lighting (long day).

Gladiolus corms are planted at 10–15 cm depth; spacing is 20–30 cm; corm rot is caused by Fusarium.

Landscape design elements: focal point, balance, rhythm, scale, unity and proportion; principles guide placement of plants and hardscape.

Landscape styles: formal (symmetrical, geometric), informal (asymmetrical, naturalistic), and free style; Mughal gardens are formal with water channels.

Lawn establishment by seeding or turfing; mowing height for most lawn grasses is 3–5 cm; regular mowing encourages tillering.

Post-harvest of cut flowers: pulsing with sugar solution, cold storage at 2–4 °C, and use of floral preservatives extend vase life.

Sexual propagation uses seeds; vegetative (asexual) propagation uses cuttings, layering, budding, grafting, suckers, tubers and tissue culture.

Cutting types: softwood, semi-hardwood, hardwood and leaf cuttings; auxin (IBA/NAA) treatment improves rooting percentage.

Layering: air layering (gootee) is used for mango, litchi and guava; ground layering for guava and bougainvillea.

Budding methods: T-budding (shield budding) and patch budding; used in rose, citrus and ber.

Grafting success requires cambial contact, compatible scion and rootstock, and proper tying and sealing to prevent desiccation.

Tissue culture (micropropagation) stages: initiation, multiplication, rooting and hardening; banana and orchids are commercially micropropagated.

Nursery management: raised beds, sterilized potting mixture (soil:sand:FYM), shade nets, and regular weeding and pest scouting.

Seed certification: foundation seed, registered seed and certified seed classes; germination percentage and purity determine seed quality.

Insect mouthparts determine control: chewing insects are controlled by stomach poisons; sucking insects by contact and systemic insecticides.

Key pests: aphids (sucking), whitefly (vector of viruses), thrips, fruit borer, stem borer, leaf miner and mites; IPM combines cultural, biological and chemical methods.

Economic threshold level (ETL) is the pest density at which control measures should be applied to prevent economic loss.

Diseases: fungal (powdery mildew, downy mildew, rust, wilt), bacterial (blight, canker), viral (mosaic, leaf curl) and nematode (root knot).

Koch's postulates establish a causal organism for a disease; symptoms, signs and isolation are used in diagnosis.

Integrated disease management uses resistant varieties, crop rotation, sanitation, seed treatment and need-based fungicide application.

Pesticide formulation types: EC (emulsifiable concentrate), WP (wettable powder), SC (suspension concentrate), G (granule); follow label dose and pre-harvest interval.

Biological control agents: Trichoderma, Bacillus thuringiensis, NPV, and predators such as ladybird beetles and Chrysoperla.

Fruit ripening is climacteric (banana, mango, tomato) or non-climacteric (citrus, grape, pineapple); climacteric fruit respond to ethylene.

Respiration rate and ethylene production determine shelf life; cooling immediately after harvest reduces both.

Pre-cooling methods: forced-air, hydro-cooling, vacuum cooling and room cooling; each suits different commodities.

Controlled atmosphere storage lowers O2 (2–5%) and raises CO2 (2–5%) and reduces respiration; CA is used for apples and pears.

Value addition: jam, jelly, marmalade, squash, syrup, pickle, ketchup, dried and canned products; FPO specifications govern quality.

Jam sets at 65–68% total soluble solids with pectin and acid; jelly requires clear fruit extract; marmalade uses citrus peel.

Grading and packaging: size grading, CFB boxes, shrink wrap, and cold chain reduce post-harvest losses.

Food preservation principles: high temperature (canning, pasteurization), low temperature, drying, acidification, and addition of preservatives.

Protected structures: polyhouse, shade net house, insect-proof net house, greenhouse and low tunnel; choice depends on crop and climate.

Polyhouse glazing materials: polyethylene film, polycarbonate, acrylic; light transmission and UV stability determine service life.

Drip irrigation with fertigation is standard in polyhouse tomato, capsicum and cucumber; EC and pH of nutrient solution are monitored.

Relative humidity above 85% in polyhouses favours Botrytis and downy mildew; ventilation and heating reduce RH.

Insect-proof nets (40–50 mesh) exclude whitefly and thrips, reducing virus transmission in protected crops.

Soilless culture: cocopeat, perlite, rockwool and nutrient film technique (NFT) allow precise control of water and nutrients.

Temperature management: fan-and-pad cooling lowers temperature by 5–10 °C; thermal screens reduce night heat loss.

Crop selection for protected cultivation favours high-value, low-volume crops such as coloured capsicum, gerbera, rose and strawberry.

Irrigation water requirement = crop evapotranspiration (ETc) − effective rainfall; ETc = ET0 × crop coefficient (Kc).

Drip irrigation saves 40–60% water versus surface irrigation; emitters deliver 2–8 L/h and are rated by uniformity coefficient.

Sprinkler irrigation suits close-growing crops; uniformity depends on pressure, spacing and wind; avoid at high wind speed.

Irrigation scheduling by soil moisture tension, pan evaporation or tensiometers; critical stages of irrigation differ by crop.

Farm machinery: tractor, mouldboard plough, disc harrow, cultivator, seed drill, sprayer, thresher and harvester; power is rated in kW or hp.

Field capacity, infiltration rate and soil texture determine irrigation depth and interval; over-irrigation causes waterlogging and leaching.

Drip system components: pump, filter, fertilizer tank, main line, sub-main, lateral and emitter; filters prevent emitter clogging.

Farm power sources: human, animal, mechanical, electrical and solar; solar pumps are increasingly used in Maharashtra for drip systems.

Farm costing: fixed costs (land, machinery) do not vary with output; variable costs (seed, fertilizer, labour) vary with output.

Gross income = yield × price; net income = gross income − total cost; benefit-cost ratio = gross income / total cost.

Marketing channels: producer → consumer; producer → retailer → consumer; producer → wholesaler → retailer → consumer; shorter channels raise producer share.

Marketable surplus = production − family consumption − seed and other requirements.

Price elasticity of demand = % change in quantity demanded / % change in price; inelastic demand means price changes cause small quantity changes.

Agri-entrepreneurship: agri-clinics, custom hiring centres, nursery enterprises, food processing units and protected cultivation ventures.

NABARD, SFAC and state schemes provide credit and subsidies for horticulture, drip irrigation and protected cultivation.

Value chain and FPO (Farmer Producer Organization) models improve bargaining power, grading, branding and direct marketing.