Potato

Seed Production

Seed production techniques

Type of seed potato

• There are two types of seed potato, viz., those grown on hills of Northern India and those grown in the plains during rabi cropping season.
• Hill-grown potatoes are raised in the hills of 2500 meters altitude or in situations found technically suitable for seed production.
• Plains - grown potatoes are raised in only such plains where aphid infestation is low and which are technically suitable for seed production under the "seed plot Technique".

Seed Plot Technique of potato seed production The essentials of this technique for seed production in the plains are:

• Start with disease-free seed stock.
• Select suitable locations (aphid-free during crop growth)
• Adopt seed certification principles.
• Rogueing and inspection of crop.
  1. Good crop management
  2. Timely planting.
  3. Raising the crop on not too rich soils (judicious manuring)
  4. Use of pre-sprouted tubers and spacing them relatively close.
  5. Restricted irrigation after the crop tuberised well: withhold irrigation 10-15 days before hauls are cut.
  6. The hauls should wilt before aphids build up population by the end of January.
  7. If the crop is still green, kill the hauls with a 2 per cent solution of copper sulphate or cut green hauls.

Essential features of potato seed production under seed plot technique in the plains

Land requirements

• Production of seed potato should not be taken up in the areas where aphid infestation is high and where the previous season potato was infected by brown rot, wart or nematode.
• Preference should be given to a 2-3 year crop rotation.
• The soils of selected field should be well drained, porous, deep and having a pH range of 5.2-6.4.

Isolation requirements

• Provide an isolation distance of 30 meters between two plots of seed potato to prevent the spread of diseases.
• However, an isolation of five meters is enough for certification purpose.

Brief cultural practices

Land Preparation

• Prepare the seed field to a good tilt by deep ploughing twice to thrice followed by harrowing and leveling. Incorporate about 25 tonnes of FYM or compost.

Time of Sowing

• The sowing should be done from end of September upto middle of October. Delayed planting will result in poor yields.

Source of Seed

• Obtain molecules/foundation seed from the approved source.
• Seed rate
• Seed-rate depends upon tuber size. About 25-30 quintals of seed potato per ha will be sufficient if the usual sized tuber (4-6 cm in diameter) are used. If the tubers are cut, each piece should have 2-3 well developed eyes and should weigh 35-45 g.

Fertilizers

• Apply 62.5 kg N, 100 kg P₂O₅ and 125 kg K₂O fertilizers per ha as basal dose at the time of planting and the remaining 62.5 kg N as top-dress about four weeks after planting.

Methods of sowing

• Whole tubers should be used for planting.
• Tubers should be under sprouting (sprouts 0.5 to 1.0 cm long) for quick emergence.
• After October 15th when the temperature goes down, cut-tubers can also be used for planting as per prevailing local practices.
• Care must be taken that each piece to be used for planting has 2-3 emerging eyes and weighs atleast 40g.
• By this practice the seed rate is reduced considerably.
• After cutting every tuber, dip the knife in alcohol or spirit or 10 per cent formalin solution to check the spread of bacterial disease carried through tubers.
• Dip the seed tubers in a solution of Mancozeb (4 g) or mercuric chloride (2.5 g) or captafol (2.0 g/litr of water) for 5 minutes and dry in shade before sowing, to prevent decay of seed tubers.
• Plant the tubers in furrows spaced 50 cm apart at 15-20 cm between seed tubers, not deeper than 3-4 cm. Seed tubers should not come in contact with fertilizers, which should be placed 5 cm below and 5 cm away from the seed potato.

Irrigation and intercultural

• Potato requires light and frequent irrigations.
• Give subsequent irrigations once in 5-7 days depending upon soil moisture and weather conditions.
• Regulate the irrigation after the crop has tuberised.
• Withhold irrigation 10-15 days before hauls (Arial shoots) are cut.
• Keep the field free from weeds. Atleast one earthing-up is necessary.
• It should be done when plants attain the height of 15 cm, which occurs about 30 days after sowing.
• Exposed tubers should be covered with soil during earthingup, which is done after top-dressing with nitrogen fertilizer.

Plant protection

Insects

• Apids, leaf hopper, epilachna beetle, cut worm, tuber worm and root grub.

Diseases

• Early blight, late blight, bacterial brown rot, leaf roll, mosaics and root-knot nematode.

Control Measures

• Use seed tubers, which are free from bacterial brown rot.
• Dip the seed tubers in the solution of Mancozeb (4.0 g) or Mercuric chloride (2.5 g) or Captafol (2.0 g) in one litre of water, for 5 minutes before sowing.
• Apply 50 kg Heptachlor 6 per cent or 50 kg Aldrin 5 per cent of 50 kg Chlordane 5 per cent per ha to control termites.
• Spray the crop with 40 g carbaryl or 5 ml phosphamidon or 17 ml dimethoate or 10 ml methyl parathion and 28 g Zineb or Duter or Maneb in 10 liters of water, three weeks after planting. About 360 liters of spray mixture is required per ha.
• Repeat the same spray mentioned in item 4 above, 5 weeks, 7 weeks, 9 weeks and 11 weeks after sowing. Use 450-625 liters of spray mixture per ha.

Haul cutting

• The hauls must be cut by the end of December or atleast by the first week of January depending upon the date of planting.

Rogueing

• Very careful rogueing is required for producing a high quality, disease free seed potato. It should be done at three stages.

First Rogueing

• Should be done 25 days after planting to remove all virus affected plants, all plants apparently belonging to other varieties (off-types) which can be identified based on foliage characters.

Second Rogueing

• Should be done when the crop is fully grown. This would be about 50-60 days after sowing. At this time tubers are formed and, therefore, while rogueing, not only the upper portion of plant, but all the tubers belonging to that plant should be removed carefully. At this stage the virus affected plants as well as off-types, if any, should be removed.

Third Rogueing

• Third rogueing is the final rogueing. It should be done just before cutting the foliage (hauls). Foliage should not be cut unless this rogueing is completed. At this stage, all virus affected plants and off-type plants, if any, along with their tubers have to be very carefully removed, so that no such plants are left in the field.

Harvesting

• The potato seed crop is ready for harvest 10 to 15 days after haul cutting when the skin of tubers has hardened.
• Pre mature harvesting causes handling problems, as the soft skin gets easily peeled off and further, such tubers can not with stand long transportation and storage.
• The harvesting is done by digging the tubers carefully to avoid cuts and bruises.
• At the time of potato digging, the soil should have optimum level of moisture to obtain clean tubers.
• After harvesting, tubers should not be left exposed to hot sun for a prolonged period (not more than one hour).
• The harvested tubers should be immediately lifted and carried to a well ventilated shed and kept in single layer piles (1 m x 3 m) for 7-10 days so that the superficial moisture evaporates and further hardening of skin curing is achieved.

Sorting and grading

• Properly cured seed potatoes should be graded by hand, based on size. A single grade from 2.5 to 5.5 cm could also be made.
• While grading, the shape, colour and depth of eyes of tubers should be critically examined and off-types discarded.
• In addition to off-types, the tubers with cuts, bruises, cracks or damaged, or showing visible symptoms of late blight, dry rot, charcoal rot, wet rot, scab or black scurf should invariably be removed.
• The visible symptoms of different potato diseases are as follows:

Disease	Symptoms
Late blight	Sunken purple spots on the surface of tubers, and the flesh has brown necrosis.Brown patches on the surface of tubers, and these patches enlarges and become sunken.
Dry Rot	The skin becomes wrinkled in the form of irregular concentric rings.Black areas appear initially around eyes and lenticels of tubers, then the spots spread further and ultimately cover the whole tuber.
Charcoal rot	On cutting the tuber the internal tissues show black patches beneath the affected areas.Affected tubers have chocolate colour sclerotic on the tubers. Often known as dirt that will not wash off.
Black scurf	The sclerotic appears on the surface as hard bodies, and may be minute or as large as peas, and may cover greater part of tuber.

Packing and storage

• After sorting and grading, the seed potatoes should be put in clean strong jute bags (50 kg size)with proper labeling.
• Soon after packing, the seed potatoes should be moved to the end-use areas for cold storage.
• If the ambient temperatures are above 32°C, the seed potatoes should first be kept in precooking chambers, or in a cool place for preconditioning and then stored in cold storage at temperatures ranging from 2.2°C to 3.3 °C and at 75-80 per cent relative humidity.
• Periodic inspection of seed stocks in cold storage is necessary to ensure that the stocks are keeping good condition.
• Turning of bags during rainy season helps in improving aeration.

Seed yield

• An yield of about 12-15 tonnes of seed potatoes can be expected per hectare.

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Minimum seed certification standards

Field Inspection

• A minimum of four inspections should be made as follows
• The first inspection shall be made about 35 days after planting (in the plains) to verify isolation distance. Off-types and the extent of disease inspection with specific reference to mild and severe mosaic, leaf roll, yellows, brown rot and other relevant factors.
• The second inspection shall be made about 60-65 days after planting for early varieties and about 70-75 days after planting for late varieties or at appropriate growth stage depending on the crop duration to check isolation distance, off-tupes and extent of disease infection with specific reference to mild and sever mosaic, leaf roll, yellows, brown rot and other relevant factors.
• The third inspection shall be made immediately after the hauls are cut and destruction of the same in order to verify that hauls have been cut/destroyed by the prescribed date and in proper manner.
• The fourth inspection shall be made about 10 days after hauls cutting/destruction and before harvesting in order to verify that no regrowth of haul has taken place.

Field Standards

Isolation

• The fields of seed potato shall be isolated from the contaminants by providing five meters distance between two plots of potatoes.

Specific Requirements

Factor Stage	Maximum permissible limits (%)
	Foundation seed		Certified seeds
	Stage-I	Stage-II
Off-types (I & II inspection) Plants showing symptoms of	0.05	0.05	0.10
Mild mosaic (I & II inspection)	1.0	2.0	3.0
Severe mosaic leaf roll, yellows.	0.5	0.75	1.0
*Total virus (I & II inspection)	1.0	2.0	3.0
**Plants infected by brown rot (Sin. Bacterial wilt) (I & II inspection)	None	None	3 plants/ha
***Regrowth of plants (IV inspection) after removal of hauls.	0.50	0.50	0.50

• Of the two inspections, the higher virus percentage will be considered for the purpose of the specified limits of tolerance.
• The presence of brown rot infected plants within the specified limits of tolerance shall be permitted in the rows known to be infected with this disease.
• In case of plants suspected to be infected with brown rot, the neighboring plants, one on either side should also be rogued along with the tubers.
• Standards for re-growth after destruction of hauls shall be met at the fourth inspection to be conducted about 10 days after hauls cutting.

Note

• All off-type plants and diseases plants should be rogued-out along with the tubers and destroyed.
  1. Gaps in the seed plot should not be more than 10 per cent.
  2. Hauls must be destroyed as close to the ground as possible before the date specified by the certification agency. Failure to destroy hauls in time shall render the crop liable for rejection.

Seed standards

Specification for seed tuber size and weight for foundation (stages I & II) and certified class

Size	Mean length and two widths at the middle of tuber	Corresponding weight
a)	Hill seed (HS)Seed size 30 mm - 60 mmLarge size above 60 m	25-150 gabove 150 g
b)	Plain seed (PS)Seed size 340 mm - 55 mmLarge size above 55 mm	5-125 gabove 125 g

Note

• The size of tuber will be decided either on the basis of mean of two widths of a tuber at the middle and that of length or on the basis of corresponding weight of tuber.
• In a seed lot, tubers not conforming to specific size of seed shall not exceed more than 5.0 per cent (by number).
• A) The seed material shall be reasonably clean, healthy firm and shall confirm to the characteristics of the variety. The tubers not conforming to the varietal characteristics shall not exceed 0.05 per cent and 0.10 per cent (by number) for foundation and certified seed classes, respectively.
  B) Cut, bruised, unshaby, cracked tubers or those damaged by insects, slugs or worms shall not exceed 1.0 per cent (by weight).
  C) Greenish pigmentation on tubers would not be a disqualification for certification.

Maximum tolerance limit of tubers showing visible symptoms caused by the diseases

Factor Stage	Maximum permissible limits (%)
	Foundation seed		Certified seeds
	Stage-I	Stage-II
Late blight, Dry rot or Charcoal rotWet rot *Common scab ** Black scurf ***Total disease	1.0% (by number) None3.0% (by number ) 5.0% (by number) 5.0%	1.0% (by number) None 3.0% (by number) 5.0% (by number) 5.0%	1.0% (by number) None3.0% (by number) 5.0% (by number) 5.0%

• Even if a single tuber infected with common scab is detected in a seed lot, the entire seed lot shall be treated with approved fungicide before seed lot is declared fit for certification.
• Seed lots having infected tubers more than the prescribed limits will not be certified even after treatment.
• Seed lots having black scurf infection more than the prescribed limits could be certified after treatment with approved chemical/fungicide.
• For all diseases, the higher disease percentage will be considered for the purpose of the specified limits of tolerance.

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Factors affecting the quality of potato tubers

• There are numerous factors, which affect the potato quality, and some of them are discussed below:

Hereditary

• This is also known as varietal or genetic characteristic, which includes mealiness, consistency, colour, flavour, sugar content and tendency to blackening.

Edaphic factors

• Soil conditions. Sandy soils produce better quality tubers than heavy soils. Both flavour and consistency of boiled potato are found to be better in potatoes produced from light sandy or red soils than those from clayey, silty or any other heavy soil types.
• Topography. Potatoes produced on hills are of superior quality than those produced on the plains because of least attack of insect, pest and various types of diseases.

Climatic conditions

• Rainfall. The crop affected by rains is found to be inferior in quality than the tubers produced under absence of rains. This is because of the fact that wet season/weather favours the attack of some insects/pests and diseases and the quality is thus found to be impaired.
• Temperature. Air temperature governs the blackening of tubers. It has been found that little or no blackening developed in tubers when the average air temperature was between 70-80° F, it was medium when temperature was between 60-70° F and it was too much when temperature was between 50-6-° C.
• Light. The bright sunny days or more light intensity results in a high specific gravity, dry weight and mealiness of tubers.

Cultural practices

• Earthing operations. Earthing helps in covering the tubers, which are otherwise exposed and form Solanin, an alkaloid (non edible and bitter tubers in taste). These exposed tubers start sprouting and remain smaller in size. Thus the quality of tubers produced under proper earthing condition are better than those not earthed properly.
• Effect of Plant protection chemicals. Use of insecticides had no effect on quality but application of 2,4-D + M.H (Malleic Hydrozide) at full blame stage was found to increase the starch and nitrogen content of tubers and prevented sprouting loss in weight of tubers during storage conditions.
• Effect of manures and fertilizers. Organic manures are found to improve the quality. The potato plants prefer ammoniac form of nitrogen in their early growth. Similarly chloride ions interfere with starch formation and finally the yield is reduced.

Biotic factors

• Attack of insect, pest and diseases not only reduce the tuber yield, but also impair the quality of the produce.

Storage conditions

• Storage of tubers at 6° C temperature increases sugar content of the tubers while at 4° C temperature a considerable loss in ascorbic acid (vitamin C) takes place. The lower temperature in store inhibits the sprouting, results in a loss of water (at 0-5° C) and the tissues become soft.

Cooking process

• The cooking process also controls the quality of tubers such as steaming potatoes show more losses than boiling in water.
• Vitamin B and C are soluble in water, hence if the water used for boiling is thrown the quality is reduced.
• Apart from this, boiling potatoes in presence of salt, causes further reduction in quality.
• The losses can be reduced if the potatoes are kept first in cold water and then put for boiling instead of putting them directly in boiling water.

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True Potato Seed (TPS)

• Potato is clonally propagated through seed tubers, which results in vigorous plants, uniform tubers and high yield with early maturity.
• But seed tubers are imported at high cost and about 3 t/ha would account to 30 to 40 per cent of the total cost of production.
• This can otherwise be diverted as a marketable produce.
• Seed tubers are often a source of pests and disease besides adding to the high costs of storage, and transport.
• Seed tubers may arrive late in the season with delayed planting.
• Further, the important seed tubers may not suit the local conditions.
• But the botanical seeds are free from diseases, with reduced cost of production.
• Hence, true potato seed (TPS) has opened new vistas in the production technology.
• TPS is being commercially used in China and Sri Lanka.
• It is cheaper and 100 gram seeds would suffice for one ha.
• Disease transmission is relatively less in TPS and seedlings are resistant to late blight.
• But the crop raised from TPS is less uniform in size, colour, cooking quality and invariably less vigorous, low yielded than from seed tubers.
• The seedlings from TPS are vulnerable to insects and environmental stress.
• Proportion of small tubers is high in crop raised from TPS.
• The inherent defect of TPS is a slow growing in early stages and long duration.
• TPS takes 6 to 7 months in comparison to 4 to 5 months required by seed tuber crop.

The production methods for TPS include

a. Direct field sowing
b. Transplanting from nursery bed to field
c. Planting of tubers or tuberlets derived from TPS.

• The first method requires cold temperature and very fine seedbed. In an organic soil, 1 million seeds per ha are sown (500 to 600 g) with localised direct seeding in 40,000 hills/ha.
• Uniform distribution of seed is difficult under field conditions.
• Seed pelting may help in uniform distribution and establishment.
• However, this method is not practical.
• Seedlings are raised on a fine seedbed, which is well watered and manured.
• The optimum temperature for seed germination is 5° C to 20 °C but below 10 ° C and above 25 ° C may be detrimental which results in low germination.
• Seedlings in the nurseries can be carefully managed to produce vigorous seedlings.
• Best results are obtained from a seedbed with peat moss : sand : plant organic matter (2 : 1 : 1) and initially some shade is provided one week before pulling.
• Transplanting shock is given by withholding watering or full exposure to sunlight.
• Transplanting is done when seedlings are 25 to 40 days after sowing having 4 to 5 leaves and 8 to 12 cm high.
• The seedlings are transplanted before tuber initiation as they yield significantly higher than those bearing small tubers.
• In general, the TPS hybrids were superior to open pollinated ones.
• In the field 3 to 4 seedlings or plantlets are planted at a distance of 30 cm with 90 cm between rows.
• Thus on optimum density is 100,000 plants (main stem) which can be achieved by planting 0.15 to 0.2 million seedlings per ha.
• This is also cost effective.
• Another practical method is growing seed tubers (tuberlets) from TPS.
• In this method, seedlings are grown in nurseries at high densities (e.g. 100 seedlings per m2). The nursery is 1 m wide, 3 to 4 m long.
• It is filled with 1 : 1 ratio peat moss and sand to a depth of 25 cm.
• The seed distribution is in a square pattern (10 x 10 cm), well manured and watered.
• Hilling has increased tuber number per plant, but not yield.
• Increased tuber number was more due to large proportion of small size tubers (<10 g).
• It is seen that multiplication rate is high with smaller size tubers and the optimum seed tuber size is 25 to 30 mm.
• The crop is harvested 120 days after sowing and stored for 4 months.
• About 100 m2 nursery space is required to produce seed tubers for 1 ha for ware potatoes.
• In summary, TPS cultivars particularly hybrids are potential means of overcoming many diseases, storage and transport problems inherent in vegetative propagation.
• Karnataka state has been identified as a thrust area for introducing TPS technology in view of its large requirement of seed tubers to the tune of 60,000 to 70,000 tonnes per annum from North Indian States.
• Almost entire seed requirement of the state is being presently met through imports from other states.
• Hence, research on the use of 'True Potato Seed (TPS)' as an alternative to traditional 'seed tubers' as planting material is of late receiving major attention in the state.
• From the results obtained, it was inferred that under irrigated conditions during rabi season on sandy loam soils (Alfisols) of Bangalore region, potato crop grown from TPS seedlings gives higher and economical yield of ware potato (marketable tubers) when two seedlings of 30 days old are transplanted at a moderate spacing of 45 cm x 20 cm with an application of 25 per cent more fertilizers (156.25 - 125.00 - 156.25 N, P₂O₅ and K₂Okg/ha) than the recommended dose of seed tuber potato crop.
• However, in terms of incremental cost : benefit ratio (ICBR), moderate spacing of 45 cm x 20 cm (1 : 40.00) and application of the recommended dose of fertilizers (125-100-125 N, P₂O₅ and K₂Okg/ha) of seed tuber potato crop (1 : 3.28) was optimum for ware potato (marketable tubers) production from TPS seedling.
• Productivity of tubers from TPS seedlings can be increased, if due attention is paid to the nutrient management.
• Among the primary nutrients, potassium is the third limiting nutrient which is involved in activating number of enzymes.
• Deficiency of potassium causes reduced size of tubers in potato.
• In sandy clay loam soils (Alfisols) of Bangalore in Eastern dry zone of Karnataka, application of 180 kg K₂ Oper ha and in two splits (50% basal _ 50% TD at 30 DAT) gives higher yield of marketable tubers (ware potato).
• In order to realise the economical optimum yield of marketable tubers (ware potato), the present recommendation of 120 kg K₂ Oper ha in two splits instead of basal application of potato crop grown from seed tubers also holds good for crop grown from TPS seedlings during rabi season under irrigated conditions.
• Application of potassium at 125 kg/ha in combination with sulphur at 25 kg/ha is better for getting economic optimum yield of potato.
• Spacing of 30 cm x 15 cm and a fertilizer level of 150 : 100 : 150 kg NPK/ha could be followed for seedling tuber production in southern dry region of Karnataka.
• Raising of healthy and vigorous seedlings from True Potato Seed in nursery bed is of great importance for potato production by TPS transplants.
• The seedbed media, seedling management practices and environmental condition influence the quality of seedlings.
• The emergence and vigour of seedlings are problems when TPS is sown under different soils of poor physical and fertility conditions.
• Among the containers tested, the seedlings raised in seed pan recorded tuber yield of 271.65 q/ha compared to nursery bed (232.41 q/ha) amounting to an increased yield of 16.88 per cent compared to nursery bed.
• Among the growing media, a ratio of 1 : 4 : 1 sand, FYM and red earth respectively recorded tuber yield (255.63 q/ha) compared to 1 : 1 : 1 growing media which recorded an yield of 248.41 q/ha with an increased yield of 2.90 per cent.
• Spray of NAA (50 PPM) GA (500 PPM) BA (5 PPM) recorded an yield of 299.49 q/ha followed by spray of NAA (20 PPM) + GA (200 PPM) ba (2 PPM) with an yield of 269.00 q/ha whereas control recorded an yield of 187.58 q/ha with an increased yield of 59.78 per cent and 43.48 per cent over the control.
• By adopting the above said agrotechniques the yield of potato can be enhanced.
• On theoretical considerations and on the basis of studies conducted so far, it is expected that the TPS technique should succeed in regions where good quality seed tubers are hard to get and expensive to buy; and where the crop seasons are mild to allow growth of the seedlings after transplanting.
• On this analogy, TPS technology should play a vital role in transitional zone of Dharwar where incidentally, such situations prevail.
• It has been the fact that potatoes under Dharwar conditions put-on excessive vegetative growth at the cost of tuber initiation and development.
• In recent years, efforts have been made to exploit yields of crops by restricting the vegetative growth by use of chemicals.
• Study in this regard indicated a crop with good establishment can be sprayed with mapiuat chloride at a concentration of 600 PPM after 30 days of transplanting to check the vegetative growth and to improve the marketable yields.
• Further the study also indicated following findings.
• An open pollinated TPS JX/C-166 was found a par excellent genotype except that its tubers were comparatively less uniform than hybrid TPS, HPS 7/67 which was the next best for the total yield. Through use of these genotypes it is possible to produce ware potatoes as much as that of tuber planted crop.
• The seeds of these genotypes can be easily produced under conditions existing in south India an can be made available to the farmers at a lower cost unlike the seed tubers of the traditional varieties.
• They do not need elaborate storage too.
• Raising of seedlings of these genotypes in the nursery beds during the months of May-June can give out transplantable seedlings by 30 days and can be planted when there is enough soil moisture preferably during days of drizzling rains that are common in the potato belts of Dharwar and Belgaum districts.
• It is essential to nourish the land with a fertilizer dose of 50 : 75 : 50 kg NPK per ha before planting the seedlings at a distance of 50 x 10 cm.
• The trials conducted at Dharwar during last few years under the
• All India Coordinated Potato Improvement Project (ICRIP) and in the horticulture Division, University of Agricultural Sciences, Dharwar have shown that the performance of the TPS hybrid population HPS 7/67 as transplants for ware potato production was quite encouraging even under rainfed culture.
• But the information on the agrotechniques for maximising the seedling tuber production of this hybrid is lacking. The field experiments conducted at the Main Research Station (MRS), University of Agricultural sciences, Dharwar during kharif and Rabi seasons of 1996-97 have revealed that the seedling tuber yields in kharif (24.78 t/ha) and rabi (22.37 t/ha) were comparable indicating the suitability of raising TPS crops for seedling tubers during both the seasons.
• Further the studies have also indicated that the population density of 200 plants/m² (26.51 t ha-1) out yielded that of 100 plants/m² (20.55 t ha-1) followed by yield (24.93 t ha-1) in population density of 267 plants/m² during kharif 1996. Yield attributing characters such as weight of tuber at 60 DAT, tuber number both at 60and 75 DAT and growth parameters like leaf area at 30, 60 and 75 DAT, plant spread at 45 DAT were found significantly influenced by population densities.
• Hence, investigations undertaken at Agricultural research Station, Madenur (Hassan district) representing the
• Southern Dry Zone of Karnatka have revealed that direct sowing of HPS-I/13 and HPS-7/67 genotypes in beds with a media containing sand, red soil and FYM (1 : 1 : 2) and application of 175 : 140 : 175 kg NPK/ha were found to be the best for production of seedling tubers.
• Raising of ware potato through transplants was not successful under Madenur situation.
• Crop raised from seedling tubers of HPS-I/13 (11-208 and 21-40 g size) was found better in production of water potato.
• The highest cost benefit ratio was obtained crop raised from seedling tuber than transplants and seed tubers.

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