|Solanum tuberosum subsp. var.||Potato|
The potato is a starchy, tuberous crop from the perennial Solanum tuberosum of the Solanaceae family (also known as the nightshades). The word potato may refer to the plant itself as well as the edible tuber. In the region of the Andes, there are some other closely related cultivated potato species. Potatoes are the world's fourth largest food crop, following rice, wheat, and maize.
Potato plants are herbaceous perennials that grow about 60 cm (24 in) high, depending on variety, the culms dying back after flowering. They bear white, pink, red, blue, or purple flowers with yellow stamens. The tubers of varieties with white flowers generally have white skins, while those of varieties with colored flowers tend to have pinkish skins. Potatoes are cross-pollinated mostly by insects, including bumblebees, which carry pollen from other potato plants, but a substantial amount of self-fertilizing occurs as well. Tubers form in response to decreasing day length, although this tendency has been minimized in commercial varieties.
After potato plants flower, some varieties produce small green fruits that resemble green cherry tomatoes, each containing up to 300 true seeds. Potato fruit contains large amounts of the toxic alkaloid solanine and is therefore unsuitable for consumption. All new potato varieties are grown from seeds, also called "true seed" or "botanical seed" to distinguish it from seed tubers. By finely chopping the fruit and soaking it in water, the seeds separate from the flesh by sinking to the bottom after about a day (the remnants of the fruit float). Any potato variety can also be propagated vegetatively by planting tubers, pieces of tubers, cut to include at least one or two eyes, or also by cuttings, a practice used in greenhouses for the production of healthy seed tubers. Some commercial potato varieties do not produce seeds at all (they bear imperfect flowers) and are propagated only from tuber pieces. Confusingly, these tubers or tuber pieces are called "seed potatoes".
At harvest time, gardeners usually dig up potatoes with a long-handled, three-prong "grape" (or graip), i.e., a spading fork, or a potato hook.
Potatoes themselves are generally grown from the eyes of another potato and not from seed. Home gardeners often plant a piece of potato with two or three eyes in a hill of mounded soil.
Pests and diseases
There are about five-thousand potato varieties worldwide. Three thousand of them are found in the Andes alonewp. They belong to eight or nine species, depending on the taxonomic school. Apart from the five-thousand cultivated varieties, there are about 200 wild species and subspecies.wp
Standard Cyclopedia of Horticulture
|Standard Cyclopedia of Horticulture|
Solanum tuberosum, Linn. Potato. Low, weak-stemmed, much-branched perennial with tender, herbaceous tops, and perpetuating itself asexually by means of thickened or tuberous underground sts., glabrous or pubescent-hirsute: lvs. unequally pinnate, the 5-9 oblong-ovate lfts. interposed with much smaller ones: fls. variable in color, white passing through various tints and shades of purple, violet, and blue, in long-stemmed dichotomous clusters: fr. a globular berry 1/2- l in. or more in diam., usually through lack of viable pollen not produced in the highly developed modern varieties except in favored localities and in the case of certain varieties, but fruiting abundantly in S. Chile and in Peru. Temp. Andes of Peru and Bolivia.
|Standard Cyclopedia of Horticulture|
Potato. One of the most widely utilized and valuable of esculent tubers, produced underground as thickened stems. It is commonly known as the "Irish," "white," or "round" potato to distinguish it from the sweet potato; botanically it is Solanum tuberosum. See Solanum.
The potato is one of the most universally cultivated plants of the United States and Canada, and it is becoming increasingly important as an article of human food. It ranks sixth in agricultural importance in the United States. This country produces, however, only about one-fifth as much as Germany. This is due to the fact that the German consumption of potatoes per capita is about two and a half times as great as ours, and that more than 50 per cent of the German crop is used either for stock-food or for conversion into starch, alcohol, or other industrial by-products. Potatoes, at present, are used very little for these purposes in this country, less than 1 per cent being so used.
The potato is closely allied, botanically, to several powerful narcotics, such as tobacco, henbane, and belladonna, and also to tomato, eggplant, and capsicum. Potatoes contain a small amount of a somewhat poisonous substance. When exposed to the direct rays of the sun and "greened," the deleterious substance is so greatly increased that the water in which they are boiled is not infrequently used to destroy vermin on domestic animals. In any case, the water in which potatoes are cooked should not be used in the preparation of other foods.
The potato is a native of the elevated valleys of Chile, Peru, and Mexico, and a form of it is found in southern Colorado. It probably was carried to Spain from Peru early in the sixteenth century. It seems to have been introduced into Europe as early as 1565. Sir Walter Raleigh, in 1585, is said to have brought back the potato from the "new country." Recent investigations, however, seem to give the credit of introducing the potato into England to Sir Francis Drake, in 1586. As Batatas virginiana, it was figured and described by Gerarde in 1597. It is probable that these circumstances led erroneously to giving the credit of introducing the potato to Raleigh instead of to Sir John Hawkins. The wild varieties in their native habitat still bear a close resemblance to cultivated varieties except for the enlarged vine and abnormal development of the tubers in the latter. In the seventeenth century the potato was cultivated in gardens in several European countries. It was recommended by the Royal Society of London in 1663 for introduction into Ireland as a safeguard against famine. The cultivation of the potato as a field crop became somewhat common in Germany soon after 1772, at which time the grain-crops failed and potatoes were a welcome substitute for the bread-corn. It was near the middle of the eighteenth century before it acquired any real importance in Europe, outside of Ireland and a few restricted localities in other countries. As late as 1771 only a white and red variety were mentioned in one of the most important English works on gardening.
The plants were enormously productive, but the tubers were poor in quality, so poor in fact that their chief use was as a food for domestic animals; and only when the bread-corns failed were they used to any extent, and even then only as a substitute. By 1840 the potato had been largely substituted in Ireland for the cereals and other similar food-crops, as the yield of potatoes in weight exceeded by twenty to thirty times the yield of wheat, barley, or oats on an equal area of land. This large dependence on a single food-crop finally resulted in a wide-spread famine.
The roots of the potato are distinct from the tubers. Usually, two to four roots start from the stalk at the base of each underground stem which, when enlarged at the end, forms the potato. Roots may also start where underground stems are wanting. The potato is a perennial plant. The accumulated starch in the tubers furnishes an abundant supply of nourishment for the plants growing from the eyes or buds until they are well above the ground. So much food is stored that not infrequently small young tubers are formed on the outside of the potatoes left in the cellar during the summer. Potatoes grow from 2 to even 3 feet high, have smooth, herbaceous stems, irregularly pinnate leaves, and wheel-shaped flowers, varying in breadth from 1 to 1 1/2 inches and in color from bluish white to purple. They bear a globular purplish or yellowish fruit or seed-ball of the size of a gooseberry, containing many small seeds. As many as 297 seeds have been found in a single seed-ball.
The cultivated potato of today has undergone a remarkable change since its first introduction into Europe by the Spaniards. Some of this change has been brought about by better cultivation, but most of it is due to breeding. The tubers of the wild S. tuberosum were small and attracted little attention. Heriot, in his report on Virginia, describes the plant "with roots as large as a walnut and others much larger ; they grow in damp soil, many hanging together as if tied on ropes." The modern potato has been bred so that the hills contain four to six tubers of uniform size, weighing, perhaps, two pounds.
The main potato industry in the United States is confined to several potato-growing sections in widely separated parts of the United States. The most important of these are Aroostook County, Maine; the Norfolk and Eastern Shore trucking regions of Virginia and Maryland; the Red River Valley of Minnesota and North Dakota; the Kaw Valley of Kansas; the Greely and Carbondale districts of Colorado; the Twin Falls country of Idaho, and the San Joaquín and Sacramento valleys of California. In these regions, the climate and soil are perfect for the best potato- production.
There are many hundred varieties of potatoes. The older varieties run out in the course of time and are supplanted by new ones. The running out is largely due to the fact that growers, as a rule, do not practise seed-selection. The new varieties are ordinarily produced either from hybridized seed or from bud-sports. The latter are somewhat common. Red tubers are now and then found in white hills, and vice versa. Other differences are taken advantage of by breeders.
Of the many varieties listed in seedsmen's catalogues and found on the market, however, only a very few are of commercial importance. Fitch, of the Iowa State College, has made a thorough trial for a number of years of all varieties of commercial importance in the Unites States and Europe. He also made a canvass in person and by letter of the markets of the United States. The result was that only a few varieties were found to be of much market value. He lists the following varieties as being the most valuable in the United States in order of their importance: Rural New Yorker, Green Mountain, Early Ohio, Burbank, Irish Cobbler, Bliss Triumph, Peerless (Pearl). Many other varieties, of course, have local importance and perhaps outyield the standard varieties named above.
New varieties are being produced constantly, a very few of which may prove to be better than the standard sorts, but most of them are worthless.
William Stuart, of the United States Department of Agriculture, has recently made a very comprehensive and admirably arranged classification of potatoes, as follows :
Group 1. Cobber.
Tubers: Roundish; skin creamy white. Sprouts: Base, leaf- scales, and tips slightly or distinctly tinged with reddish violet or magenta. In many cases the color is absent. Flowers: Light rose- purple; under intense heat may be almost white.
Group 2. Triumph.
Tubers: Roundish; skin creamy white, with more or less numerous splashes of red, or carmine, or solid red; maturing very early. Sprouts: Base, leaf-scales, and tips more or less deeply suffused with reddish violet. Flowers: Very light rose-purple.
Group 3. Early Michigan,.
Tubers: Oblong or elongate-flattened; skin white or creamy white, occasionally suffused with pink around bud-eye cluster in Early Albino Sprouts: Base light rose-purple; tips creamy or light rose-purple. Flowers: White.
Group 4. Rose.
Tubers: Roundish oblong to elongate-flattened or spindle- shape flattened; skin flesh-colored or pink, or (in the case of the White Rose) white. Sprouts: Base and internodes creamy white to deep rose-lilac; leaf-scales and tips cream to rose-lilac. Flowers: White in sections 1 and 2; rose-lilac in section 3.
Group 5. Early Ohio.
Tubers: Round, oblong, or ovoid; skin flesh-oolored or light pink, with numerous small, raised, russet dots. Sprouts: Base, leaf-scales, and tips more or less deeply suffused with carmine-lilac to violet-lilac or magenta. Flowers: White.
Group 6. Hebron.
Tubers: Elongated, somewhat flattened, sometimes spindle- shaped; skin creamy white, more or less clouded with flesh-color or light pink. Sprouts: Base creamy white to lilac; leaf-scales and tips pure mauve to magenta, but color sometimes absent. Flowers: White,
Group 7. Burbank.
Tubers: Long, cylindrical to somewhat flattened, inclined to be slightly spindle-shaped; skin white to light creamy white, smooth, and glistening, or deep russet in the case of section 2. Sprouts: Base creamy white or faintly tinged with magenta; leaf-scales and tips usually lightly tinged with magenta. Flowers: White.
Group 8. Green Mountain.
Tubers: Moderately to distinctly oblong, usually broad, flattened; skin a dull creamy or light russet color, frequently having russet-brown splashes toward the seed end. Sprouts: Section 1 base, leaf-scales, and tips creamy white: section 2 base usually white, occasionally tinged with magenta: leaf-scales and tips tinged with lilac to magenta. Flowers: White,
Group 9. Rural.
Tubers: Broadly round-flattened to shortroblong, or distinctly oblong-flattened; skin creamy white, or deep russet in the case of section 20. Sprouts: Base dull white; leaf-scales and tips violet- purple to pansy-violet. Flowers: Central portion of corolla deep violet, with the purple growing lighter toward the outer portion; five points of corolla white, or nearly so.
Group 10. Pearl
Tubers: Round-flattened to heart-shape-flattened, usually heavily shouldered; skin dull white, dull russet, or brownish white in section 1 or a deep bluish purple in section 2. Sprouts: Section 1 base, leaf-scales, and tips usually faintly tinged with lilac; section 2 base, leaf-seal , and tips vinous mauve. Flowers: White.
Group 11. Peachblow.
Tubers: Round to round-flattened or round-oblong; skin creamy white, splashed with crimson or solid pink: eyes usually bright carmine. Includes some early-maturing varieties. Sprouts: Base, leaf-scales, and tips more or less suffused with reddish violet. Flowers: Purple.
Cultivation of potatoes.
The best soil for potatoes is a sandy loam, well drained but provided with an abundant supply of water. If the soil is deficient in moisture, the water from rainfall must be conserved by shallow cultivation. The ground should be plowed deeply and worked thoroughly so as to bring about perfect aeration. Whether the plowing should be done in the fall or the spring will depend largely upon the distribution of time and labor which the grower has at his disposal, except that hilly fields which are likely to wash during winter should not be plowed in the fall.
In cutting potatoes for planting, each eye should be supplied with an abundance of food to start the young plants vigorously. The pieces should be as large as possible and not bear more than piece two or three eyes. (See Fig. 3154.)
The potato is sensitive to frost, and therefore must complete its growth in most localities in three to six months. The period of development may be shortened by exposing the seed potatoes to the more or less direct rays of the sun in a temperature of about 60° for one or two weeks before planting. Some of the starch is transformed into sugar, which causes the eyes or buds to develop into miniature short tough plants or "rosettes" which results, when the potatoes are planted, in hastening growth and shortening the period between planting and harvesting. Some varieties, when thus treated in warm rich sandy soil, produce merchantable tubers in six weeks.
The kind and amount of fertilizer which should be applied to potatoes will, of course, vary with conditions, such as method of rotation, natural fertility of the land, methods of growing the crop and so forth. The best method of rotation is one in which a crop of clover immediately precedes the potato-crop, particularly in the North. This furnishes nitrogen and leaves the ground in good mechanical condition. Ordinarily, potatoes require a fertilizer analyzing about 4 per cent of potash, 7 per cent of phosphoric acid and 10 per cent of potash. If lime is applied to the land during the rotation, it should follow the potatoes and not precede them, as it furnishes the best conditions for the development of scab, which is a serious disease. The same is true of wood-ashes which, ordinarily, contain 30 per cent of lime.
Potatoes are planted either by hand or with a machine. Good-sized tubers should be cut into about four pieces and a single piece placed in each hill. The seed-pieces should be planted soon after cutting so as to prevent "bleeding or loss of water from the cut surfaces. The depth of planting will depend upon circumstances, but ordinarily 4 to 6 inches maybe considered an average depth. The planting-machines are usually drawn by two horses and perform several operations at once. They open the furrow, distribute the fertilizer, cover it slightly so that it will not come into direct contact with the seed, drop the seed-pieces and cover them. Sometimes a heavy wheel, to act as a roller, is attached to the rear of the machine to pack the soil over the hills. By means of these machines, large acreages may be planted in a short time.
Potato fields should be given frequent and thorough tillage to keep down the weeds and conserve soil moisture. These cultivations should be shallow to prevent injury to the roots. The soil is cultivated until the plants are large enough nearly to fill the rows and have begun to "set" tubers. Further tillage is likely to injure the plants and reduce the yield.
After the plants are mature, the tubers are dug either by hand or with an elevator digger drawn by two or more horses.
The most common enemy to the potato plant, the Colorado potato-bug, is easily destroyed by applications in a powder or in a liquid of paris green or arsenate of lead to the vines when the bugs first appear. The fungus, Phytophthora infestans, causes the true blight (Fig. 3155), which results in potato-rot. The true blight may be kept in check by frequent and thorough sprayings with bordeaux mixture. It is always well to incorporate arsenicale with the mixture, that any remaining bugs may be destroyed. The bordeaux mixture is also useful in protecting in part the plants from the flea-beetle. Two or three applications are usually made during the summer. The early blight is more common than the true or late blight. It causes the shriveling and death of the foliage. It is usually the combined result of several causes, chief amongst which are fungi, flea-beetle, drought. Thorough good care and spraying with bordeaux mixture are the best treatments. Potatoes as a market-garden or truck crop.
The chief difference between potatoes as a field crop and a market-garden or truck-farm crop is that in the former case they are grown in rotation with other long- season plants and consequently may occupy the ground for the entire growing season, while in the latter they occupy the ground only a few weeks and are usually preceded and followed by some early or late garden crop the same year. In the North the crop is usually grown in the spring and early summer, but in the South it may be grown either in the early spring or late fall. The spring crop is grown to supply the demand for new potatoes in the early markets while prices are high, but the fall
crop is mostly consumed locally either for table purposes or for seed for the next spring crop. In the trucking region of the upper South, the spring crop is planted in January, February, or March and harvested in May and June, and the fall crop in July or August and harvested in October or November.
The favorite Virginia rotation starts with potatoes planted in February and harvested in June. Cowpeas are sown immediately for a summer cover-crop; these are plowed under in August as a means of improving the soil, and spinach is planted in September. This crop is harvested in January or February and garden peas are planted in rows 5 or 6 feet apart. The peas are inter- planted in late March with cucumbers. The peas are harvested in April and May, and the cucumbers in June and July. The ground is planted to kale in August, which is harvested in midwinter and potatoes planted again in February or March. A second two year rotation starts with potatoes planted in February followed by cowpeas or an annual grass for forage. Winter cabbage is transplanted to the field in November or January. Corn is planted after the cabbage is harvested in May or June. Cowpeas are planted between the rows of corn at the last working. The cornstalks remain standing in the field until late fall when the grain is harvested and they and the pea-vines are worked into the ground to supply organic matter.
Since earliness, productiveness, and reasonable resistance to disease are the main requisites for truck- farm potatoes, the varieties that meet the requirements are limited. In the South Atlantic and Gulf states, Bliss Triumph is the leading variety, while in the Carolinas and Virginia, Irish Cobbler is the favorite; but in the upper Mississippi Valley, Early Ohio undoubtedly is in the lead.
Seed grown in Maine, Michigan, Wisconsin, or other northern states will produce potatoes of marketable size five to ten days earlier than locally grown seed. Consequently truck-farmers who wish to cater to the early market depend upon the northern tier of states for their seed-supply; but those who wish to sell on the midseason market are now largely using locally grown seed. Plants from northern-grown seed suffer more severely from certain diseases than do those from local seed, hence the extreme earliness of the crop from the northern seed is, to a marked degree, compensated for by the healthier vines and larger yield from local seed.
The seed-stock to be used in producing the home or locally grown seed is obtained from the North in the winter or early spring, and held in cold storage until July or August, when it is planted. The tubers are harvested after the vines are killed by frost in October or November, and are placed in farm storage until needed for planting.
The land should be broken with a turn-plow a month or six weeks in advance of planting the potatoes, if the preceding crop in the rotation will admit. It is best to apply the stable-manure to some preceding crop in order that it may be well decayed before the tubers are planted. After the ground is thoroughly harrowed, the rows should be marked out about 3 feet apart. If drainage is not good it is well to open the furrow with a small turning-plow in order to expose a large surface to the action of the sun, air, and frost. A few days before planting, the furrows should be reopened, the fertilizer required distributed in them. It should be thoroughly mixed with the soil to prevent its coming into direct contact with the seed-tubers when they are planted.
In forcing potatoes, especially in the cooler season of the year, it is customary to use from 1,500 pounds to 2,000 pounds of fertilizer analyzing 5 to 6 per cent nitrogen, 6 to 7 per cent phosphoric acid, and 5 per cent potash, to the acre. The potatoes will not use all of this, but that remaining after they are harvested is available for subsequent crops. About one-third of the nitrogen in the fertilizer should be obtained from nitrate of soda and sulfate of ammonia and the other two- thirds from high-grade tankage, blood, and fish-scrap. By using nitrogen from the sources mentioned, the plants are enabled to obtain a constant supply throughout their growing-season. The phosphoric acid is obtained from acidulated South Carolina rock, and the potash, preferably, from sulfate of potash. Some growers apply about 1,000 pounds of the fertilizer in the rows before the tubers are planted and the balance as a side or top dressing when the plants are well started.
Whether the potatoes are to be planted by hand or a power planter, it is better to apply the fertilizer before planting, as much better distribution may thus be obtained. The larger number of truck-farmers follow the practice of hand planting, but the larger growers are now using horse-power machines. From three to five barrels of northern-grown seed and from two to three barrels of home-grown seed are usually required to plant an acre. The seed-pieces are placed 14 to 16 inches apart in the rows and are usually placed from 2 to 4 inches below the surface-level of the ground. The hand-planted tubers are covered by turning two furrows over them with a small turn-plow, thus forming a ridge 8 or 9 inches high above the tubers. If the discs of the power planter do not form such ridges, it is customary to add additional soil with the plow. These high ridges protect the seed-tubers against unfavorable weather conditions and enables them to develop strong roots before the sprouts appear above the ground, thus insuring rapid development when the season opens.
As soon as the tubers have formed sprouts an inch or two long, a light harrow is dragged diagonally across the ridges to kill any weeds that may be starting, and to provide a mulch over the row. A second dragging is given a week or ten days later, or just before the sprouts appear above the surface. The first working with the cultivator is given as soon as the plants have the row well outlined; subsequent cultivations are given at intervals of a week or ten days, a small quantity of soil being worked against the plants, thus forming low ridges at the later cultivations. If proper attention is given to the early cultivation, little or no hoe work need be expected.
The season for harvesting depends more upon market conditions than upon the maturity of the crop. If prices are high, digging may be started when the yield will not be over thirty or forty barrels to the acre, but if prices are moderate with indications for a steady demand, harvesting may be delayed for two or three weeks. In the meantime the yield will have increased from 25 to 50 per cent.
The crop is usually turned out of the ground with a plow while the vines are still green. The vines are then pulled out of the ground with most of the tubers attached. These are carefully pulled from the roots, the others picked out of the loose soil and placed into piles on the ground. They are then graded by hand and packed in barrels for shipment. Great care is used in handling the new potatoes to prevent unnecessary bruising.
Mechanical diggers have not given satisfaction in the trucking region of the South, primarily because they bruise and break the skin, thus causing the tubers to present discolorations when placed on the market.
Potato, air: Dioscorea bulbifera. P. Onion: Onion. P., Sweet: Sweet Potato, and Ipomaea Batatas.
- ↑ http://www.hort.purdue.edu/rhodcv/hort410/potat/po00001.htm
- ↑ Growing Food: A Guide to Food Production ISBN 1402066244
- ↑ Regulation of potato tuberization by daylength and gibberellins
- ↑ "Papas Nativas de Chiloé – Descripción de tuberculos". Papasnativas.cl. Retrieved on 6 December 2009.