Continuing with the publications related to Utilitarian Botany, in the present delivery the main botanical characteristics, the phenological behavior, the agroeconomic and nutritional potential of the species Solanum tuberosum (Solanaceae) are described.
According to the reports of the statistics division of the Food and Agriculture Organization of the United Nations (FAO), the main agricultural activity that represents South American countries is the cultivation of roots and tubers, whose productive and commercial positioning over time has been related to the genetic diversity of tropical specimens that undergo stolonization and tuberization during their vegetative development .
Of the vegetables, which suffer stolonization and tuberization during their vegetative development, the species Solanum tuberosum commonly known as potato, is the crop of the area of roots and tubers of greater agronomic and economic interest in the South American countries, surpassing crops like the one; yucca (Manihot esculenta), celery (Arracacia xanthorrhiza), sweet potato (Ipomoea batatas) ocumo blanco (Xanthosoma sagittifolium), carrot (Daucus carota), radish (Raphanus sativus), beetroot (Beta vulgaris), white yam (Dioscorea rotundata), turmeric (Curcuma longa) and ginger (Zingiber officinale).
For this reason, the objective of this post is to socialize the botanical elements related to the phenological, agronomic, economic and nutritional behavior exhibited by the potato Solanum tuberosum (Solanaceae).
The Solanaceae family, belongs to the division: Magnoliophyta, class: Magnoliopsida, and is currently artificially constituted by 102 genera and 2.460 species, representing the genus Solanum the most important food taxon, being the species Solanum tuberosum (potato), Solanum lycopersicum (tomato) and Solanum melongena (eggplant), the agronomic and commercial reference materials, as far as botanical characteristics are concerned, specimens of annual duration, herbaceous biotype, berries type fruits, foliar laminae with alternate phyllotaxy, hermaphrodite, actinomorphic or zygomorphic flowers, seeds covered by mucilaginous substances, in relation to the main axis, these species present aerial stems of circular or angular morphology, soft consistency, and in the case of S. tuberosum additionally presents underground thickened stems type tuber .
Fig. 2 Extension of cultivated area of potato Solanum tuberosum. Public domain image Author: Kallerna, 2009 / CC BY-SA 3.0
Morphology of Potato
The potato Solanum tuberosum, is a species of deciduous biotype, with roots of fibrous and adventitious morphology, herbaceous stems of vertical orientation and tuberous underground stems, lanceolate leaf blades composed of an odd-looking leaflet (one leaflet at the end of the rachis), alternate phyllotaxy, inflorescences in the form of a terminal peak or umbels, berry-like fruits with an ovoid morphology, small white/yellow seeds attached to parietal placentas .
Fig. 3 Potato seedling Solanum tuberosum. Public domain image. Author: Rasbak, 2007 / CC BY-SA 3.0
Domestication of Potato
The potato, comes from the diploid wild material S. leptophyes, that after long adaptive processes, has generated to its descendant currently cultivated Solanum tuberosum, genetic material that from the agricultural point of view is placed as the fourth most important crop at world scale, only surpassed by rice (Oryza sativa), wheat (Triticum aestivum), and corn (Zea mays), however, in terms of nutritional value it is important to indicate, that the tuberous structures of S. tuberosum are characterized by a high content of sucrose, glucose, fructose and starch.
According to , the first material selected and domesticated was S. stenotomum, however, after interspecific and intervarietal hybrids the commercial material Solanum tuberosum, whose specific genetic adaptability allows its growth, development and reproduction in tropical soil and climate conditions, with minimum altitude of 2.000 and maximum of 3.2000 meters above sea level, rainfall between 400 and 800 mm during the crop cycle and 2.600 mm per year, temperatures ranging from 15 to 25°C, preferably sandy, loamy soils.
Under agronomic conditions, the potato Solanum tuberosum reproduces in a vegetative way (asexual), for that reason, in field the sprouts or tuberous buds are used, since these vegetative structures when developing produce roots and foliar tissue, nevertheless, an aspect to consider to select the material to be used (tubers) like seed, is that these have a weight average 45 grams and are free of pathogens. In relation to the phenological stages, the first phase is called emergence of sprouts, and according to  begins from day 15, and triggers the second phase or development of aerial stems and leaves for 30 additional days, which gives way to the consecutive appearance of the third phase or filling of the tubers that lasts for 45 days more, closing the phenological cycle with the physiological maturity of the tubers at approximately 120 days.
Fig. 4 Potato sprouts or tuberous buds Solanum tuberosum. Public domain image: CC BY-SA 2.0
Planting of tubers in the field
After the selection of tubers with an average weight of 45 grams and free of pathogens, we proceed to their transfer and planting in the field, at a depth of 20 centimeters, and at an estimated distance of 30 centimeters between tubers and 1 meter between rows.
Perimeter area of each seedling
Bearing in mind that the tubers of Solanum tuberosum are the organographic structures of commercial production, it must be guaranteed that these, are not attacked by plagues and diseases, nor affected by the erosion that produces the practices of irrigation on sandy, frank and silty grounds, reason why, it is recommended like agricultural practice to pile up or to add ground on the perimetral area of each seedling to a height of about 30 centimeters, action that allows the optimal development of the culture.
Control of arvens species
The herbaceous condition of the potato Solanum tuberosum, is a negative aspect for the crop, this because, in the first phases of growth and vegetative development, competition with arvenous materials is generated, consequently and considering that the first 45 days are of vital importance for the emergence and development of underground stems of potato specimens, it is advisable to start the control program of arvenous species from 15 days after planting the tubers, incorporating hoes as tools for the superficial removal of plant materials that are competing with the crop, however, in those cases where it is necessary to use chemical herbicides, you can use pre-emergent products that stop the growth of arvenous species.
The two main microorganisms, which affect the potato crop Solanum tuberosum are Phytophthora infestans fungus responsible of causing important damages at foliar level, the name that receives the disease that produces this pathogen, is called Late Blight, and it is characterized by producing reddish and black spots in all the limb, the control method used and of better results to fight it, consists on leaving greater distance between seedlings and rows, as soon as, To the pathogen that affects the tubers, the one that generates the greater ravages on the production is the microorganism Rhizoctonia solani, fungus that acts on the sprouts and underground stems, causing delays of growth, development and maturation in the tubers, reason why, in plantations attacked by this microorganism the recommendable thing is to apply fungicides based on the active ingredient carboxin .
Fertilization and productivity
As any other crop, to program a fertilization plan in the potato Solanum tuberosum, crop, it is recommended to carry out a nutritional diagnosis at edaphic level by means of soil analysis, in the search of adding only the required quantities and that generate nutritional balances, now, according to  1 ton of S tubers. tuberosum extracts about 6, 0.8 and 9 kg/t of nitrogen, phosphorus and potassium, with an estimated yield of 25 t/ha, on the other hand, in investigations developed by , the doses projected for the crop are located approximately in 270, 130, 385 kg/ha of nitrogen, phosphorus and potassium.
Fig. 5 Harvested potato tubers Solanum tuberosum. Public domain image: CC BY-SA 3.0
According to the data, reported by the Statistics Division of the Food and Agriculture Organization of the United Nations - FAO-STAT, the yields per hectare of potato Solanum tuberosum are above 165 million tons of tuber/hectare/year.
Table. 1 Main producing countries of Solanum tuberosum, according to :
Table. 2 Main South American countries producing of Solanum tuberosum, according to :
The culture of potato Solanum tuberosum, is characterized essentially by the high content of carbohydrates that possess his tubers, in addition near 60 % of the dry matter of these eatable structures is starch, in relation to the values of protein the varieties of potato present ranges similar to the cereals.
Table. 3 Nutritional composition of potato tubers Solanum tuberosum according to :
|Total fat (g)|
|Vitamin C (mg)|
SCIENTIFIC CONTRIBUTIONS OF THIS PUBLICATION
- The main botanical characteristics of the family Solanaceae were highlighted, particularly the morphological attributes of the species Solanum tuberosum, highlighting the presence of tuberous underground stems, and also pointing out the interspecific and intervarietal hybrids of S. stenotomum, that gave rise to the formation of the commercial material S. tuberosum. As for the agronomic content, the information shared provides technical elements related to the requirements of the tubers for planting in the field, taken from the perimeter area of each seedling, recommendations for the elimination of arvenous species under two control methods, phytosanitary control of the two main pathogenic microorganisms for the crop, and indications for programming fertilization plans.
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