Production Technology of Citrus

Soil Wide range of soil including Deep sandy loam, clay and

clay loam soil Very heavy, sandy, alkaline and waterlogged soils not

suitable Thrive best in sandy loam or loamy soils Tolerate pH range of 5.5-8.5 Soil type correlated to rootstock Punjab………………….Rough lemon KPK………………………..Sour orange

Propagation Asexual methods Sexual methods Rootstock propagated sexually by seed Seeds germination percentage

Rough lemon 70-80% Sour orange 60% Seeds sown on seedbed in September or Feb-Mar Ready for transplanting after 6-12 months 1-year after transplanting seedlings are ready to transplant

Grafting and Budding Budding and grafting done during active growth period

Spring or Autumn T-Budding T-Grafting

Scion Mature wood with white streaks

Cutting…………….Sweet limeLayering…….Kaghzi Lime

Planting system and planting time Planting time Spring and autumn

Spring March-April Autumn August-September

Commonly plated in square system (21 or 18 feet) High density citrus plantation (14 feet) However rectangle system and hexagonal system also

followed in some area No. of plant per acre

Irrigation time

Irrigation methods FloodBorderBasinModified basinFurrow Drip

Modified basin system

Drip irrigation

Diseases of citrus

1. Citrus scab2. Citrus wither-tip / Dieback3. Citrus greening4. Citrus canker

Citrus scab (Elsinoë fawcettii) Fungal disease Spores are dispersed to healthy tissues by water

splash Infects young shoots, leaves, and fruits of susceptible cultivars The yield and quality of juice can be reduced in highly susceptible cultivars (sour orange) Copper based fungicides

Citrus wither-tip/ dieback (Colletotrichum gloeosporiodes)

Fungal disease Aerial parts Wilting of branches from tip towards base Leaf fall and in severe cases tree is killedManagementCutting of affected portion Application of copper based fungicides

Citrus greening (Huanglongbing) Candidatus Liberibacter africanusCandidatusLiberibacter asiaticus Candidatus Liberibacter americanus

Bacterial disease Vector Asian citrus psyllid Leaves of newly infected trees develop a blotchy mottle appearance. Control of the disease is based on planting HLB-free citrus germplasm Eradication of infected citrus plants Control of the vector with systemic insecticides

Citrus canker (Xanthomonas compestris pv citri) Bacterial disease Symptoms appear on leaves, branches and fruit Small yellowish spots on leaf These spots were turned hard and brown Kaghzi lime, grapefruit and lemons are very susceptible Management Healthy nursery Control of insect vector Spray of Bordeaux mixture

Chemical control

Physiological problems Alternate bearing Fruit drop Granulation Unfruitfulness

Alternate bearing Habit of bearing heavy crop in one year and very little

or not at all in the second year On-year and Off-year Mandarin

Kinnow, Wilking Sweet orange

Valencia Late, Washington Navel Grapefruit

Marsh seedless

Management• Improving the C:N ratio• Heavy manuring during off-year• Thinning of fruit during on-year• Delayed and early harvest during off- and on-

year, respectively

Fruit drop1. Flower drop2. Pearl drop3. June or young fruit drop4. Pre-mature drop Management Spraying growth regulators

Gibrellic acid 2,4-D (2,4- Dichlorophenoxy acetic acid) 2,4,5-T (2,4,5-Trichlorophenoxy acetic acid NAA (Naphthalene acetic acid)

Granulation Characterized by enlarged, hardened and dry juice

vesicles Large fruit are more prune to granulation than smaller

fruit Delayed harvest also increases the intensity of

granulation Frequent irrigation also intensify this disorder Mosambi, Valencia Late, Washington Navel and

Fuetrell’s Early Management

Spot picking Spray of 2,4-D

Unfruitfulness Citrus do not produce a commercial crop for many

years Incompatibility Heterostyly Ovule abortion Hormonal or nutritional imbalance Management

Root pruning Ringing of main branches Exposure of tree to drought stress or withholding nutrition

• Climatic conditions also affect the tree physiology

FLOW CHART OF KINNOW

PRE-HARVEST FACTORSPhysiological disorders:

Potassium deficiency resulting in poor growth. Calcium deficiency reduces citrus fruit color.

High temperature stress: High temperature stress effect damage to cellular membranes, proteins,

and nucleic acids.Light intensity:

Excess solar energy initially results in degradation of the pigmentation in the affected area.

MATURITY ASSESMENT

Fruit colour:Golden orange

Flesh colourPale yellow or whitish

TSS/acid ratio8 or higher with yellow-orange color at least on 25% of the fruit surface

OR 10 or higher and green-yellow color on 25% or greater of the fruit surface.

Quality Indices Color intensity and uniformity Firmness, size, shape, smoothness freedom from defects including physical damage (abrasions and

bruising), skin blemishes and discoloration, decay, freezing damage, chilling injury, and insect damage

Flavor quality is related to soluble solids/acid ratio and absence of off-flavor-causing compounds including fermentative metabolites.

HARVESTING METHOD Fruits are harvested by clipping the

stem with the help of sharp clippers The stem is cut as short as possible

to avoid mechanical injury.

PACKING Jute bag Wooden boxes Cardboard boxes

Citrus Packinghouse Operations

Dumping Washing Surface Drying

Waxing and Fungicide Application

Surface Drying Surface Drying


Stamping Individual Fruits Volumetric Sizer

Machine Vision (Electronic) Sizer

Sorted Under UV Light to Eliminate Defects

Sorting Into Quality Grades Sorting By Quality


Fruit Destined For Juice Plant Hand PackingCitrus Fruits

Pattern Packer -1


Pattern Packer -2 Packing Into Consumer Bags


Packed Boxes May Be Slightly Vibrated to Settle Fruits With the Box

Palletized Boxes In Storage Room

POSTHARVEST HANDLINGStorage Temperature:

3-8 ° C up to 3 months depending on cultivar, ripeness of the harvest and production area.

Optimum relative humidity: 90-95%. Responses to Controlled Atmospheres (CA) 5-10% O2 and 0-5% CO2 can be useful for delaying senescence and for

firmness. Ethylene production rate: <0.1 mL / kg • hr at 20 ° C. The fruit can be stored in cold storage at a temperature of 4-5°C and a

relative humidity of 85-90%. Exposure to 1-10ppm ethylene for 1-3 days at 20-30°C (68-86°F) may

be used for degreening oranges

Physiological disorders

Chilling injury Stem-end rind breakdown Rind staining. Oil spotting (Oleocellosis)

Chilling injury Stem-end rind breakdown



Rind staining. Oil spotting (Oleocellosis)

Postharvest diseases Green mold Blue mold Phomopsis stem-end rot Stem end rot Brown rot Sour rot

Green mold Blue mold

Postharvest diseases

Brown rot Phomopsis stem-end rot


Sour rot Stem end rot


Control Strategies Minimizing physical damage during harvesting and handling. Treatment with postharvest fungicides and/or biological antagonists.

Also, heat treatments may be used. Prompt cooling and subsequent maintenance of optimum temperature

and relative humidity throughout marketing operations. Removal and/or exclusion of ethylene. Effective sanitation procedures throughout postharvest handling.

Education

Production Technology of Citrus