ORIGIN
The carrot is native to central Asia and the Mediterranean. It has been cultivated and consumed since ancient times by Greeks and Romans. During the first years of cultivation, the roots of carrots were purple in color. Changing these to their current orange is due to the selection occurs in mid-1700 in the Netherlands, which provided a large amount of carotene, the pigment that causes color and have been the basis of actual plant material.
MORPHOLOGY AND TAXOMOMIA.
Family: Umbelliferae.
Scientific name: Daucus carota L.
Floor: biennial. During the first year it forms a rosette of leaves and few roots. After a rest period is presented in a short stem flowers that form during the second growing season.
Root system: root napiforme, shape and color variables. It has stored functions, and also presents numerous secondary roots that serve as organs of absorption. When performing a cross-section there are two defined zones: an outer, consisting mainly of secondary phloem and outer xylem formed by the core. Carrots most accepted are those with high proportion of outer bark and the xylem is usually woody and tasteless.
Flowers: white, with long bracts at the base, grouped in inflorescences umbel composed.
Fruit: diaquenio soldier for its flat face.
PLANT MATERIAL
TYPES OF CARROTS:
Large carrots, intended primarily for processing, but also the raw product prepared and fresh produce.
Carrots fine, washed and in bundles, for industrial use, employing long-sized varieties, which allows each piece several pieces that maintain the original form, then proceed directly to the packaging pouches that are consumed as an appetizer . This product works very well-cut produce commercially.
Carrots bunch: as a result of summer for fresh consumption. It occurs throughout the year. should be tender and sweet, while washing the carrot has to be more resistant.
Cultivated varieties:
ANTARES: adapts to the summer-autumn crops, especially in March and May sowings. Its shape is cylindrical-conical, with resistance to breakage.
BAYON F1: Amsterdam-type variety of strong blade, early completion is not at first completely round.
BOLERO: Nantes type variety, elongated carrot cut into several pieces like and take it as an appetizer. Recommended for sowing from April to June in cold areas.
CARSON F1: Chantenay type variety, characterized by its conical root.
DIAVA F1: Recommended for the entire period of cold spots (from August to January) and October to November mainly in warmer areas.
GEMINI: resistant to moisture, uniformity, earliness and little Destri.
KAROL: early variety adapted to light soils.
Karot: Flakee type variety, good external and internal color, resistant to cracking and mechanical harvesting.
TEACHER: resistant to Alternaria and cavity spot. It has a balanced proportion of leaf and root.
MAJOR: cold-tolerant variety due to its late rebound.
NANDRIN: half-cycle variety, smooth, cylindrical root.
NELSON: Early Nantes type hybrid, heavy foliage, suitable for first deliveries in bunch and summer productions in the main crop.
NENE: medium-early hybrid. It features a strong blade, smooth and fine root and grown on land that is not too sandy.
NIPPON: Nantes hybrid type of strong and long root sheet.
PLUTO: to grow in late spring and summer, is adapted to light soils and has a rapidly growing season.
AWARDS: sown between February and March, and its collection to locate during the months of July and August.
RIGA F1: Nantes variety of mid-cycle type, recommended for fall plantings.
SPLENDID F1: dual-range ability, precocious and very round finish.
TEMPO: early-cycle variety, well adapted to sandy soils.
TINO F1: Nantes type variety, cylindrical, straight, smooth and long, wash carrots good aptitude for conservation, known for its hardiness and high yields. His planting corresponds August to December in temperate zones and from February to July in colder areas.
F1 1901: sheet strong, dark, upright, perfect for a bunch, early root very smooth and is especially indicated in loose, fertile soils.
BREEDING
Studies in carrot breeding are based on the development of new varieties of green collar absent, smooth skin, good performance against a rising wing flower, disease resistance and improved yields and quality of the final product. It also is testing the strength of the leaf and root to facilitate mechanical harvesting.
Edaphoclimatic REQUIREMENTS
Temperature
This plant is very rustic, but has a preference for warm climates. Being a biennial plant, during the first year is used by its roots and in the second year, induced by low temperatures, initiates flowering and fruiting stages. The minimum temperature for growth is around 9 º C and an optimum around 16-18 ° C. Supports light frosts, at rest the roots are not affected to -5 º C allowing its conservation on the ground. High temperatures (above 28 º C) cause an acceleration in aging processes of the root, loss of color, etc..
Ground
It prefers clay-limestone soils, airy and fresh, rich in well-decomposed organic matter and potassium, with pH between 5.8 and 7. The compact and heavy land originate fibrous roots, lower weight, size and length, also increasing the risk of decay. Stony soils originate misshapen or forked roots and soil with excessive organic waste lead to corky root.
The carrot is very demanding in soil, therefore not appropriate to repeat the crop at least 4-5 years. As usual preceding crops are cereals, potatoes and sunflower. although the grain may promote disease chopped; as undesirable precedent other umbelliferous crops such as celery. Recommended as previous crops tomato, leek and onion.
SPECIAL CROP
Preparing the ground
Land preparation is usually a deep tillage (subsoiling or moldboard), followed by a more superficial harrowing work or cultivator. The seed bed is prepared with a work of shaping rotocultivador and adapted depending on whether the crop is done in plain, grooves or plateau. Usually they used plateaus of 1.5 m. and four bands of planting.
Siembra
Is nearly year round. If planting is done at random, will be used by area about 80 g of seed, leaving the final distance between plants of 15 x 20 cm, which suggests that if you are at distances of less need to proceed to the thinning of plants. The seed should be at a depth of about 5 mm.
Usually performed sowing seed drill and seed bare or calibrated bands, at a dose ranging from 1.8-2.3 million seeds per hectare.
Irrigation
It is quite demanding crop irrigation in summer, especially when performed on dry soils.
Subscriber
As a guideline lists the following subscribers:
- Poor land, per hectare: manure (30 t), 33.5% ammonium nitrate (100 kg), superphosphate of lime at 18% (400 kg), potassium chloride 50% (100 kg).
- Rich land, per hectare, 33.5% ammonium nitrate (100 kg), superphosphate of lime at 18% (300 kg), potassium chloride 50% (150 kg).
Potassium chloride and superphosphate of lime into the soil before winter. Nitrate-dressing, once or twice after the thinning.
Collection
Harvesting is done before the root reaches its full development (up to 5 cm. In diameter depending for canning or fresh consumption). The period between planting and harvesting can vary depending on the variety, the end use of the product and the time of year, being in general an interval of 3-7 months.
Harvesting operations are started, the cleaning, cutting the foliage if necessary, and collection. There are three types of collection: hand-picking, is used only in very small plots, semi-mechanical harvesting, using tools fitted to the tractor (plow blades or machine boot-liner), and mechanical harvesting, a technology currently.
Mechanical harvesting is becoming more common due to their considerable advantages such as labor savings and therefore lower production cost. In the U.S., almost all production is harvested mechanically. There are two types of machines used by the presence or absence of foliage at the time of harvest, both moving with a tractor, although there autopropuldadas machines.
Push starters machines are used to start the carrots devoid of foliage, so they are suitable for varieties of lush foliage or roots little small. The removal of foliage or previously performed in the same collection operation, coupling the tool to the tractor.
QUALITY
There are many visual and organoleptic properties that differentiate the different varieties of carrots for fresh market and minimum process. In general, the carrots should be:
Firm (not limp).
Straight with a uniform taper.
Bright orange.
Absence of lateral rootlets waste.
Absence of “green heart” by exposure to sunlight during the growing phase.
Low bitterness and terpene compounds.
High moisture content and reducing sugars is desirable for fresh consumption.
Quality defects, including lack of firmness, uneven shape, roughness, poor color, cracks, green heart, burning sun and poor quality of the cut stem.
WASHING AND CONDITIONING
The washing and conditioning operations are made in store, usually with specific machinery to avoid the blows to the carrots. For the leafless root there are lines that most machining operations: washing, sorting, grading and packaging. Carrots with leaves are washed, sorted and packaged into bundles.
These operations must be as thorough as possible, since they depend on the outcome of the product.
The process consists of the following phases:
1. Receiving roots: it is done in bins filled with water, to prevent damage that may occur in the product.
2. Separation of stones: the stones are separators vats through which water flows, and through a turbine driving the roots to the periphery by centrifugal force, leaving the stones in the center.
3. Washing: Wash prior to itself, can be pre-washed by spray nozzles, and a dry pre-cleaning. The actual washing is done manually or using washing machines, which can be rotating cylinders, washing machines and washing machines by bubbling spray. The main disadvantage of washing machines is the danger of damaging the roots. To avoid this there are “soft washing”, equipped for semi-submerged rotating cylinders, particularly suitable for early varieties.
4. Selection: This phase remains separated by a conveyor belt foliage, and also the carrot pieces or items with a rotating drum with orifice allowing passage of small pieces.
Bagging
Carrots are one of the few horticultural products which best lends itself to packaging. In the market, the carrots are tailored in sachets or bags made of polyethylene or polypropylene formats half kilo and above, with holes for ventilation. The variety of carrot bagging must have the following characteristics: early, intense color, uniformity and good finish in the field, washable and Alternaria.
This type of packaging has the following advantages:
Presence attractive.
Easy packing and heavy by the manipulator.
Deal of product freshness.
Lets see clearly the goods.
Long shelf life.
Highly publicized, both graphically and by tag attached.
Overall bagging a train comprising:
Heavy product.
Filling bags.
Closed pouch.
Proper weight control, with diversion of unfit stock.
Packed in boxes of issue.
During the operation of the bag closed, you can go the placement of a hangtag or otherwise, which maintains its right signals, especially the batch encoding
CONSERVATION
The shelf life at 0 ° C is typically:
-Tied: 10-14 days immature roots: 4-6 weeks
Fresh-Cut: 3-4 weeks, mature roots: 7-9 months
Storage conditions rarely achieve long-term optimum temperature to prevent decay, sprouting, and dehydration. A storage temperature of 3-5 ° C, mature carrots can be stored with minimal development of decay for 3-5 months.
Carrots packed in “Cello-pack” are typically immature and can be stored successfully for 2-3 weeks at 3-5 º C. Carrots are very perishable tied due to the presence of stems. Generally able to maintain a good quality with only 8-12 days, still in contact with ice.
Minimally processed carrots (fresh-cut, sliced ??and peeled) can maintain a good quality for 2-3 weeks at 3-5 ° C.
The optimum relative humidity ranges from 98-100%, it is essential to high relative humidity to prevent dehydration and loss of crispness. The free moisture in the washing process or condensation not evaporated, common in plastic bags, promotes the development of decay.
PESTS AND DISEASES
Pests
CARROT-FLY (Psylla rosae)
The adult measures 4.5 mm and has brown head and black elongated abdomen. The larva is yellowish white, bright, and 7-8 mm. length and nicknames. Iverna on the floor in puparium. making their appearance in spring.
-Biology: ovopositan on the floor or other crops (celery, etc.).. At ten to twelve days, leaving the larvae penetrate into the root, dig down a gallery that reaches almost to the end of the root. After a month, into nymphs. Adults make their appearance in mid to late July and then pupate.
-Damage: The larvae enter the root, where they practice winding galleries, especially on the outside, which subsequently will decay origin, if conditions are favorable there is a loss of market value of the estate under attack.
-Control: soil fumigation and / or disinfection of seeds. It recommends the application of 0.5% tefluthrin presented as granules at doses of 10-15 kg / ha.
-APHIDS (Cavariella aegopodii, Aphis spp., Myzus persicae)
Besides causing direct damage, aphids are vectors of viral diseases, so they are doubly dangerous.
-Damage: Aphids feed the skin itching, so strong curl produced in the leaves take on a yellowish color.
-Biological control: There are many predators of aphids as Coccinella septempunctata, Chrysoperla and some hymenopterous parasites that develop their larvae inside the aphid.
-Chemical: Contact aphicides be used in the case of the aphids are not protected inside the curled leaves, using as active materials: Malathion, Diazinon, Fenitrothion, etc. In the case of aphids radicicol tefluthrin 0.5% will be used the same dose given for the carrot fly.
-Cutworm (Agrotis genus)
-Damage: The caterpillars eat the aerial parts of plants during the night, while they remain in soil or under leaves during the day.
-Chemical: Here are the active substances authorized and still effective:
-Wireworms (Agriotes obscurus, A. sputator, A. lineatus)
-Damage: attacking the roots of the carrot producing galleries that sometimes generate rot.
-Control: at planting time is recommended to deposit Diazinon 10%, presented as a pellet in the floor at a dose of 45 kg / ha.
-Nematode (Heterodera carotae, Meloidogyne spp.)
Heterodera carotae is a very important and widespread pest in temperate climates, the symptoms of attack are very small plants with foliage and reddish leaves. The roots are reduced and are forked, causing abnormal hair dark rootlets.
Meloidogine spp. spreads in warm climates, producing significant damage to the roots, turning them into strings of guts.
-Physical methods: one method is very effective, and used both in nurseries and in greenhouses, is to treat the soil with hot water, because the nematodes are killed at temperatures of 40-50 ° C.
-Cultural Methods: soil organic matter provides the basis, crop rotation (inserting non-sensitive plants), disinfect implements, machines, wheels, etc.. Who have been working in contaminated areas and cleaning of weeds, with many species of nematodes are polyphagous.
Diseases
-Downy mildew (Plasmopara nivea)
- Control: It is very convenient the use of fungicides as a preventive measure or to the beginning of the first symptoms of the disease. The frequency of treatments should be under normal conditions every 12-15 days. If during the interval from treatment to treatment rain, another spray should be applied immediately after the rains.
-Powdery mildew (Erysiphe umbelliferarum, Leveillula taurica)
-Damage: attacks produced by both fungi are similar, they are characterized by the formation on the surface of the leaves of a type of white rot and dirty up of conidiophores and conidia.
-Control: we recommend the following active ingredients:
-Chopped or CAVITY-SPOT (Pythium violao, P. sulcatum, P. intermedium, P. rostratum)
This is one of the most problematic diseases in growing carrots.
-Damage: root on small spots appear translucent elliptical contours defined. These spots rapidly evolving light brown depressions, causing a collapse and a darkening of the beds of surface cells.
-Preventive Measures are based on: design a good drainage system, avoid heavy soils, crop rotations and nitrogen fertilization reasoned.
-Chemical Control: Apply Metalaxyl 5%, presented as a pellet at a dose of 20-40 g / ha.
LEAF-BURN (Alternaria dauci)
The disease appears during the summer and autumn, hot and humid environments.
-Symptoms first appear as small brownish spots, halos of yellow and scattered along the edge of the leaves. By increasing the number spots intermediate tissues die, so that the leaflet is dried completely. The plant appears to be sunburned or ill-treatment made.
The fungus can cause very large plant emergence yore to be carried by the seeds and, later, cankers on the main root.
-Control: treated seed should fight the disease and any of the active substances recommended:
Physiological & Physical Disorders
-Bruises, drilling and split ends: these are signs of careless handling. Nantes carrots are particularly susceptible type.
-Emergence: carrots occurs when new shoots develop after harvest. This is one reason why it is essential to managing post-harvest low temperature. Commonly associated disorders include wilting, dehydration or the development of texture “rubbery” due to desiccation.
Root-white: A disorder is due to suboptimal production conditions resulting in patches or streaks of color on the roots of the carrot.
-Bitterness: Stress can be pre-harvest (often inadequate irrigation) or exposure to ethylene from ripening or mixtures with other products such as apples.
-Freezing injury: results at temperatures of -1.2 º C or lower. Frozen carrots generally exhibit an outer ring of infiltrated tissue, seen in a cross, which turns black in 2-3 days.
-Whitening, due to dehydration of the tissue cut or peeled by abrasion, has been a problem in fresh cut carrots. Using sharp knife blades and residual moisture on the surface of processed carrots may significantly delay the development of the disorder.
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