Seed Potato

Potato Seed Production Technology

The potato is tuberous crop contains a huge amount of starch its botanical name is Solanumtuberosum L. The word "potato" may refer either to the plant itself or the edible tuber. It is native to Andes region. Potatoes were introduced outside the Andes region approximately four centuries ago, and have since become an integral part of much of the world's food supply. It is the world's fourth-largest food crop, following maize, wheat, and rice.

Selection of high-quality seed is essential for the production of a profitable potato crop. Your best assurance of avoiding seed-related problems is to use only certified seed. This article describes the aspects of seed selection that you should consider before purchasing seed for commercial potato production.

Potato Seed Production is a difficult job because of fallowing reasons.

n  High rate and Cost

n  Quick degeneration

n  Seed flow

n  Multiplication in spring or quality seed available during spring

n  Lack of coordination

n  Private sector is in non technical hands

Causes of Degeneration of Seed Stock

a.       Vegetative propagation

b.      Tuber-borne and Soil-borne diseases

c.       Viruses (virus Y, PLRV, Mosaics and phytoplasma)

d.      Fungal (Powdery Scab, Rhizoctonia solani, Verticillium  and Fusarium wilt,)

e.      Bacterial (Common Scab)

f.        Cyst nematodes

g.       Physiological degeneration (young seed, Old seed, Long storage,

h.      Mechanical damages ( Transportation, Storage conditions, Methods of storages, Packing)

i.        Sowing conditions, Climatic changes etc

Basic Principles of Quality Seed Production

n  Selection of Suitable Sites

Topography/location.

1.       Slope greater than 10% is not good

2.       Concentration of cooler air in low areas.

3.       Affect irrigation practices

4.       Nutrients and pesticide leaching.

5.       Soil properties.

                   1. Good water holding capacity.                    2.    Good drainage.

                   3. Land leveling.                                            3.  Soil pH 6.5 optimum 6 to 7.5 suitable.

6.       Cropping history.

                      1. Continuous production of crops belonging to same family   is not recommended.

                      2. Crops grown prior to potatoes should not be host of fungal pathogens.

                      3. Insect such as wireworm, white grubs and Nematodes.

Water availability:  Potato needs a light but regular supply of irrigation

Soil:       Sandy loam soils are usually considered as the most suitable soils.

Seed bed Preparation.

To obtain a rapid growth the seed tuber must be planted in fairly moist, loose soil. The soil under the seed bed should not contain compacted layers.

Plains.

n  7 - 8  ploughing.

n  3 - 4  planking.

Mid hills.

n                  5 - 6  ploughing with 2-3 planking.

High hills.

1 - 2  ploughing before winter.

                2 - 3  ploughing with 1-2 planking at the time of planting

Seasons
For seed multiplication are Autumn and Summer
(20 aphids per 100 compound leaves or 3 for sticky traps and 2 aphids /day con. In yellow water                tray)  

n  Seed Tubers.    

1.            without mixture of other varieties.

2.            Free from diseases.

3.            be physiologically mature.

n  Seed Rate.

                                CROP                     SEED RATAE KG/HA

n                  Autumn                               2500 – 3000

n                  Spring                                  1500 – 2000

n                  Summer                               1500 – 2000

n  Seed Size.

                35 mm to 55 mm OR    40 – 50 grams weight.

n  Planting depth.

n                  7 – 15 cm.

n                  Cooler regions: 5 to 7 cm or below 10 cm.

n                  Warmer regions: 11 to 15 cm or above 10 cm.

n  Sallow Planting (When)                                               Deep Planting (When)

n  Soil is heavy.                                                     - Soil are light.

n  Seed tubers are not vigorous.                    - Seed tubers are vigorous

n  Soil temperature is low.                               - Soil temperature is high.

n  Irrigation water is frequently                     - Soil is dry at the time of  planting.

n  Planting Distance.

It depends on. varieties, growing conditions, desired tuber size, Plant to plant distance:  15 – 20 cm for ware potato and  10 – 15 cm for seed potato.

Optimum density:   20 – 25 stems per M2 for general crop. More than 30 stems per M2 for Seed crop.

Row to row distance.   65 – 75 cm row to row distance should be maintained

n  Weed Management.

n  Crop rotation.

n  Hot and cold weather cultivation.

n  Good seed bed preparation.

n  Proper planting.

n  Manures and fertilizers.

n  Physical methods/manual.

n  Mechanical method.

n  Chemical.

WATER MANAGEMENT.

n  Excess soil moisture-can delay emergence and promote bacterial seed piece decay.

n  Leaches nitrate nitrogen.

n  Flooding: 8-12 hours can cause root death.

n  The goal of water management is to maintain adequate soil moisture throughout the growth of the crop.

n  Fertilizer Use

NITROGEN

n  Nitrogen is required to promote the vegetative growth.

n  Quick mergence and vigorous growth.

n  Nitrogen affects the thickness of the stem.

n  Quick availability of nitrogen in the soil accelerates root growth.

n  Higher the dose, greater is the probability of delay in tuber development.

DEFICIENCY SYMPTOMS.

Entire plants may turn light green. Older leave turn yellow to light brown and young leaves remain green.

RESPONSE TO NITROGEN APPLICATION.

Potato crop removes about 120 kg N/ha in the hill soils.

Potato crop removes about 140 kg N/ha in alluvial soils of plains.

PEAK PERIOD OF NITROGEN UP TAKE.

40 -60 day is plains.                        60 – 80 days is hills.

Higher dose of Urea affects and delays the germination due to accumulation of ammonia and nitrites.

POTASSIUM.

n  This nutrients influence both yield and tuber quality.

n  It balances the effects of both nitrogen and phosphate.

n  It improves the taste of the produce.

PHOSPHOROUS.

n  This nutrient contributes to early development and tuberization.

n  Maximum availability of phosphates PH 6.7 and 7.00.

n  Banding method is much better than Broad cast.

Start with basic seed if basic seed is not available then select healthy plants.

1.            Single eyes from the rose-end of each tuber is scooped out and planted in a screen house.

2.            First year clones: Nucleus tubers are planted at 1 x 1 m spacing to avoid transmission of contagious                 viruses

3.            Second year clones: the produce of the first ear selection is grown (10 tuber selected per clone) at inter                 row spacing of 1m with 30 cm plant

4.            Third year clones: The clones of the second year selection are planted at spacing of 75x 30 cm,   separately about 100 tubers per clone

5.            Rouging

During the crop season, examine the seed plot thrice to remove off-type and diseased plants showing mosaics, crinkling, rolling of leaves marginal florescence and purple top roll symptoms. First rouging done 25-30 days after planting and immediately before earthling up. Second rouging should be done 45-50 days after planting. Third rouging, if needed, should be done 3-4 days before haulm killing. Care should be taken to ensure that all the tubers of the diseased and off type plants are also removed.

Haulm killing:

                Kill the haulms of the crop in the last week of December or when 3-5 aphids/100 compound leaves are observed in the field. Ensure that re-growths do not appear on after dehaulming, as tender and succulent leaves are even more attractive to the aphid

Harvesting and grading:

Harvesting should begin 10-15 days after haulm killing when the skin of the tubers has become firm. Harvesting should not be delayed under any circumstances. Keep the freshly harvested tubers in heaps in a cool place for about 10 days.

The size of the heap should be about 1.5 m high and 3.5 m broad.

Cover the heaps with paddy or wheat straws to protect them from direct sunlight. If it rains during the period the heaps should be covered with tarpaulin. Grade the tubers according to their size preferably in four grades, small (below 35 gm), medium (35-55gm), and extra large (above 75 gm). .

Seed storage: store the seed bags in a cold store latest by 5th March; otherwise, the rising temperature will deteriorate the quality.