Ipomoea batatasSweet potato

World Production

Taxonomy

Kingdom: Plantae (Plants)Subkingdom: Tracheobionta (Vascular plants)

Superdivision: Spermatophyta (Seed plants) Division: Magnoliophyta (Flowering plants)

Class: Magnoliopsida (Dicotyledons) Subclass: Asteridae

Order: Solanales Family: Convolvulaceae (Morning-glory family)

Genus: Ipomoea L. (morning-glory) Species: Ipomoea batatas (L.) Lam.

sweetpotato

BotanyIt is the only hexaploid (6x = 90) in this section

its origin is unknown

Section Batatas contains approximately 12 other species

most are diploid (2n = 30)a few tetraploids (4x = 60).

Tetraploid sweet potatoes have been collected in the wild although rarelyIpomoea trifida, a diploid, is purported to be one of the likely progenitors of sweet potato.

BotanySpecies in section Batatas have been shown to contain unreduced gametes

the derivation of the hexaploid sweetpotatoremains a mystery

The major center of diversity for I. batatas:northwestern South America (northern Peru, southern Ecuador)sub-Saharan AfricaPapua New GuineaIndonesia

Morphology

leaves ovate-cordateborne on long petiolespalmately veinedangular or lobed

depending on varietygreenpurplish.

Morphology

flowers rare, especially in US like common morning glory

white or pale violetaxillaryfunnel-shapedborne singly or in cymes on short peduncles; pods round; seeds 1–4 per pod, flattened, hard-coated, angular.

GermplasmsReported from

the Indonesia-IndochinaMiddle and South American Centers of Diversity

more than forty cvs that have been grown in the US, about 10 are of commercial valuetwo categories:

food types feed types.

further divided into dry or firm types and moist or soft types.

Sweetpotato

Potato

Peanut

VarietiesThe present outstanding soft-fleshed cvs

'Porto Rico', 'Nancy Hall', 'Triumph', and'Australian Canner';

firm-fleshed types'Big-stem Jersey','Yellow Jersey', 'Maryland Golden', and 'Orlis' (Jersey orange).

EcologySweetpotato is cultivated

in tropicalsubtropical lowland agroecologies

The crop will grow with between 15°C and 35°CStorage roots are sensitive to changes in soil temperature depending on stage of root developmenta drought-tolerant crop

deep rooteddeveloping storage roots under very dry conditions

grow best in a sandy loam, well-drained soilhave been produced at altitudes >2000m and as far north as Canada.

MorphologyTuberous-rooted perennial,

usually grown as an annualtop herbaceousdrying back to ground each year

stems forming a running vine up to 4 m longusually prostrate and slender with milky juicelateral stem-branches arising from the short stemusually not branched.

Ecology

tolerate annual precipitation of 3.1 to 42.9 dm (mean of 153 cases = 15.0), pH of 4.3 to 8.7 (mean of 88 cases = 6.4)Well-adapted to tropical and subtropical climatesDays and nights must be fairly warm.

Ecologyfairly drought-tolerantSoils must be well-drained. Subsoils of clay are satisfactory unless they are tight and stickySome friable, well-drained loams and silt loams are highly productiveExcellent soils have surface layers more than 30 cm in depth, those from 15–30 cm are considered goodSlopes should be gentle, with little tendency to become eroded.

CultivationIn tropical areas, sweetpotatoes flower and cross-pollinate easilyseeds are rarely used for propagation purposespropagation is by vegetative means, from transplants produced by bedding mother roots, or from rooted cuttings. grown over a wide range on farms of various types:

truck farms, dairy farms, cotton farms, tobacco farms, corn-and-hog farms,and others..

HarvestingSweetpotatoes develop a substantial amount of the total yield in the last 4–5 weeks before frost. For large yields 130 to 150 days growth is required. Early harvested crops are lower in carotene content and in total solids. Probably the best time to harvest for storage is after the leaves show slight yellowing. A 16- to 18-inch tractor-drawn turning plow with a vine-cutting colter in front of it is probably the best tool for harvesting.

Yields and Economics Average yields vary from 17.5 to 27.5 MT/ha, depending on the cv and growing conditions . Sweetpotatoes have long been considered the second most important vegetable crop in the US, second only to white or Irish potatoes. Spain is major producer in Europe; India grows sweetpotato in all states and it ranks third in importance among tuber crops, exceeded only by potato and cassava. In China, where it was introduced in 1594, sweetpotato is often used more than rice and has been used to relieve famines.

Biotic Factors Sweetpotato is subject to injury from a number of diseases that may attack the young plants in the hot bed or the growing crop in the field or may cause decay in storage. The worst of these are stem-rot, black-rot, foot-rot, soft-rot or ring-rot,and in the Southwest, root-rot. These are described and illustrated, and control measures are given in Farmers' Bulletin No. 1059, Sweet Potato Diseases. The sweetpotato is not seriously injured by many insects but the sweetpotato root weevil has been very injurious in sections of the South, especially in the Gulf States.

Pests and Diseases

Cutworms frequently destroy the young plants by cutting them off soon after they are set in the field . Agriculture Handbook No. 165 (1960) lists the following as affecting this species:

Albugo ipomoeae-panduratae (white rust), Alternaria sp. (secondary leaf spot), Aspergillus spp. (secondary storage rot),

Pests and DiseasesBotrytis cinerea (gray-mold rot), Cercospora sp. (leaf spot), Choanephora cucurbitarum (leaf mold), Coleosporium ipomoeae (rust), Diaporthe batatas (dry rot of roots, stem rot), Elsinoe batatas (spot anthracnose), Endoconidiophora fimbriata (black rot of roots and stems), Epicoccum sp. (storage rot), Erwinia carotovora (bacterial soft rot), Fuligo violacea, Fusarium oxysporum (surface rot of roots in storage), F. oxysporum.f. batatas (stem rot), Helicobasidium purpureum (root rot), Hypomyces ipomoeae, Macrophomina phaseoli (charcoal rot of stored roots, stem rot),

Pests and DiseasesMeliola clavulata and M. malacotricha (black mildew), Monilochaetes infuscans, Mucor racemosus (storage rot), Penicillium sp. (bluemold rot), Pestalotia batatae (on roots), Phyllosticta batatas (leaf blight), Phymatotrichum omnivorum (root rot), Physarum cinereum, P. plumbeum, Phytophthora sp. (root rot), Plenodomus destruens (foot rot of stems and roots), Pyrenophora terrestris (pink rot), Pythium spp. (rootlet rot, mottle necrosis of mature roots, leak and ring rot in transit and storage), Rhizoctonia solani (sprout rot, rootlet rot, stem canker), Rhizopus spp. (soft rot, ring rot of stored roots), Schizophyllum commune (dry rot of roots),

Pests and DiseasesSclerotinia sp. (storage rot following chilling), S. minor (sprout rot in seedbeds), Sclerotium rolfsii (southern blight, cottony rot),Septoria bataticola (leaf spot), Streptomyces ipomoea (soil rot), Trichoderma spp. (punky rot of stored roots), Verticillum albo-altrum (wilt) (Ag. Handbook 165, 1960). Several viruses are known to infect sweetpotatoes:

A virus, B virus, Feathery mottle (sweetpotato internal cork virus), Mottle and Mosaic,Tobacco mosaic, Vein-clearing, andMizugusare disease.

Internal brown spot is due to boron deficiency.

Pests and Diseasesmany nematodes have been reported on the crop:

Aphelenchoides besseyii,Aphelenchus avenaeBelonolaimus gracilisB. LongicaudatusCriconemella onoensisDitylenchus destructorD. dipsaciHelicotylenchus multicinctusH. CavenessiH. ConcavusH. MicrocephalusH. PseudorobustusHemicriconemoides cocophillusMeloidogyne haplaM. IncognitaM. incognita acritaM. Javanica

Nothotylenchus affinisPratylenchus brachyurusP. CoffeaeP. PratensisP. PenetransP. ScribneriP. ThorneiP. ZeaeQuinisulicius capitatusRadopholus similisRotylenchulus reniformisScutellonema brachyurumS. ClathricaudatumTylenchorhynchus annulatusT. claytoni, and Xiphinema americanum

Insects attacking sweetpotato plants:Long-horn beetles (Cerambicid), Sweetpotato flea beetle (Chaetosnema confinis), Wireworms (Conoderus amplicollis, C. falli, C. vespertinus), Sweetpotato weevil (Cylas formicarius elegantulus), Cucumber beetles (Diabrotica balteata and D. undecim-punctata), American plum borer (Euzophera semifuneralis), Wireworm (Melanotus communis), Tortoise beetles (Metriona sp.), Flower beelte (Notoxus calcaratus), Variegated-cutworm beetles (Systena blanda, S. elongata, S. frontalis), Sweetpotato leaf-beetle (Typophorus nigritus viridicyaneus). Methods for control should be obtained from local agricultural agents

Pests and Diseases

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