strawberry

strawberry

  The strawberry (Fragaria vulgaris L.) is a plant native to America and belonging to the botanical family Rosaceae. The strawberry plant is a perennial plant of high nutritional quality: Strawberry is rich in vitamins C, B1 and PP P. It is also rich in mineral salts, which is suitable for elderly people on a slimming diet and fabric softener. The main production regions are the Souss, Gharb and Loukkos.
Pedoclimatic preferences:
  The strawberry is a fruit that requires rosacea cold to flower initiation and for good production. The cooling requirements are low for hot or temperate zone cultivars, "southern varieties" when they are bred for cold areas cultivars such Gorella. If these needs are not met, floral initiation will be very small and poor fruiting. These low temperatures are to be suffered by strawberry plants to enable them flowering. Floral period they are unfavorable (sagging flowers). The average temperature for a good bloom is of the order of 10 to 15 ° C. Good fertilization requires a temperature of 20 ° C and a relative humidity below 60%. Normal fruit ripening requires a temperature above 15 ° C and the optimum growth temperature is around 25 ° C with a growth arrest at temperatures below 5 ° C. Cultivation of strawberry is also influenced by the brightness. Thus in long days the plant produces stolons. This plant undergoes two growth, the first held in warm weather and long days. It is characterized by a high production of sheets (up to a week) and an upright; second growth taking place in the early fall, gives the plants a stocky appearance. Flower initiation is triggered by the occurrence of short days, but when the short day are maintained during an extended time, they cause dormancy of plants. To overcome this dormancy, the plants should be exposed to a low temperature (2 ° C-10 ° C). The higher this temperature, the shorter the required duration of exposure to cold. The central flowers are those that provide the biggest strawberries, so it will protect them from frost. The fruit size is the number of fertilized achenes. Several growth regulators exist to improve this fertilization (auxins, gibberellins, cytokinins, growth inhibitors, growth retardants, ethylene and ethylene generating products). As regards the requirements of the culture soil, although the strawberry suits a wide range of soils, it prefers hot land light texture. He fears compacted soils or not draining and dread the chlorides even at low doses of the order of 0.5%. The optimum pH of the soil should be between 5.7 and 6.5 and the lime content should be less than 2%.
Varieties, tillage and seeding:
The main varieties used in Morocco are of 3 types: (1) remontant varieties (they go back a second time during the production of the year in the case of recollected, Marastil, American remontant, Brighton, Selva) (2) Non remontant varieties (large fruited strawberry giving one crop per season) and (3) Errors semi upbound (intermediate between the remontant varieties, not remontant). The varieties are known by their precocity (Chandler, Guariguette, Douglas, Osso Grande and La Selva is asexual multiplication of strawberry and it is through plants These are of two types:. (1) Fresh Plants (covering them. cold in need in high altitude nurseries. They are planted in late October early November) and (2) refrigerator plants (sorted and stored in cold rooms to 2 ° C. The cold storage lasts 6-7 months before their use . by fraiseriste) The ground work needed in general before planting are: means plowing (30 cm), two crossed harrowing and rolling to spray the soil surface The plastic mulch is generally used in strawberry.. As for planting, it can be flat, but most often it is done on ridges (raised beds or 10- 20 cm above the ground). Planting dates vary greatly depending on the type of plant used, the general climate of the region and selected varieties. In Morocco, optimum planting dates are located: (1) between November 10 and December 15 for fresh plants and (2) between 1 July and 15 August for plants "Fridge". The use of fresh plants is preferred; the period November-December seems appropriate for the Tadla region. The recommended planting density is 70,000 plants / ha (with 4 lines per sheet of 1 m wide and 0.5 m spacing between the boards).
Irrigation and tending:
  Strawberry thrives in areas that receive annually more than 500 mm of well distributed rain. Where rainfall is insufficient or poorly distributed (if Tadla), irrigation is necessary. Needs during the growing season is 420 mm on average. Two additional irrigation (100 mm) during the period of fruit formation increases the yield. The best irrigation system used in Morocco is the drip (not wet leaves and flowers). Fertigation is increasingly used also. Are tending cutting stolons, leaf removal, weeding and aerating Nantes tunnels.
  Fertilization:
The basal dressing consists of 40-60 t / ha manure + 50 kg / ha of N + 100 kg / ha of P2O5 + 100 kg / ha of K2O. On the cover, it brings 100 kg of ammonium nitrate (33 kg / ha of N) + 260 kg / ha of potassium nitrate (20 kg N + 104 kg K2O) + 240 kg of sulphate of potash (K2O 110 kg) + 200 kg of MAP (24 kg N + 110 kg P2O5) + 100 kg of Mg sulphate (either close to 80 kg / ha 110 kg N + P2O5 / ha K2O + 214 kg / ha). These quantities can be made by fertigation and divided into 20 inputs (1 times / week). The split may be lower if little soil leaching.
Main enemies of culture and Controls:
  The main strawberry disease are (1) the rhizome rot (Phytophthora cactorum). This parasite persists in the soil and requires two sprays at a dose of 5 kg / ha of Al phosephyl 80% emergence. (2) red heart disease of strawberry (fragaria photophtore) is treated at maneb. (3) powdery mildew (sphaerotheca macularis); is treated with sulfur. (4) purple spots disease (treated with fungicides like Maneb, mancozeb or captan). (5) gray mold (Botrytis-cineria); must be treated preventively and ventilate the tunnel. Pests are numerous (nematodes, mites, aphids). Viruses also attack culture at different stages (or marbling fleck caused by the VPS virus, yellow SWYE edge caused by the virus, of the winding caused by SVB; SCV virus ... etc). Prevention measures are classic (fight against weeds and virus vectors, aphids especially, crop rotation and choice of good plant material unharmed virus).
Harvesting and product handling:
  The harvest is staggered, the fruit is harvested by hand every 3-4 days at the optimum stage of maturity (strawberry farm can support the various processes of handling and transportation). Given the fragility of strawberries, it is recommended to use scissors by cutting the fruit stalk and avoid as much contact strawberry-hand could damage the cutter. Harvesting should be done in the morning after the disappearance of the morning dew to avoid softening of the fruit.
Terms of good conservation:
  The optimum storage temperature depends on the duration for the conservation: a few hours (at 12 to 15 ° C), 24 hours (5to 8 ° C)-1 to 2 days (at 2 to 3 ° C), 3 5 days (0 to 0.5 ° C). Conservation can be changed in atmosphere (low C02 concentration of 10-15% and low oxygen levels to 2 ° C); strawberries retain their firmness, appearance and color for 8 days. Conservation can be done by ionization (it involves subjecting the strawberries to ionizing radiation using gamma rays emitted by a radioactive source rays or accelerated electrons from a particle accelerator .This preservation method delays ripening of strawberries can be easily stored for 10 days, even at 13 or 15 ° C.

Agronomic and Veterinary Institute Hassan II