ADVANCES IN PRODUCTION TECHNOLOGY OF SWEET POTATO

1. PRODUCTION TECHNOLOGY AND CROP
IMPROVEMENT IN SWEET POTATO
B. PAVAN KUMAR NAIK
1st PH.D HORTICULTURE
ANNAMALAI UNIVERSITY

2. SWEET POTATO
Scientific Name: Ipomoea batatus
Family: Convolvulaceae
Chromosome No: 2n=90
Native: Tropical America

3. Since roots contain 16%
starch and 4% sugar, it is
used for production of
industrial starch, syrup
and alcohol.
It is mainly used for
human food after
boiling or steaming,
baking or frying and
also as animal feed.
Sweet potato
is cultivated
for its sweet
root tubers

4. How The Sweet Potato Crossed The Pacific Way

6. Distribution
It is an important tuber crop
in tropical and sub-tropical
countries like Africa, China
and India.
In India, it is grown mainly in
Andhra Pradesh, Assam, Bihar,
Tamil Nadu and Orissa

7. HEALTH
Rich in β-carotene
Good source of Vitamin C
Good source of Vitamin B6
Good source of fiber
Excellence source of phenolic
compounds
Excellent source of
Anthocyanins
Good source of Minerals (Fe,
K, Ca, Mg, Zn)
BENEFITS
Antioxidant
Anti-diabetic
Anti-inflammatory
Anti-cancer
Cardioprotective
Anti-obesity
Combat Vitamin A
malnutrition
Mohammad Khairul Alam, 2021

8. Health benefits, in vitro and in vivo, of sweet potato roots and leaves were
presented.
Orange-fleshed sweet potato varieties are superior source of β-carotene (pro-
vitamin A).
Purple-fleshed sweet potato varieties have the excellent levels of anthocyanins.
Sweet potatoes could be utilized as potential material for novel products
formulation.
Compared to other commonly consumed leafy vegetables such as spinach, the
sweet potato leaves as well as roots contain significant higher amount of protein.
The sweet potato is reported to be superior sources of polyphenols, terpenoids,
saponins, glycosides, alkaloids, steroids, and other functional bioactive
component.
Alam et al., 2016

9. SPECIES OF SWEET POTATO
Species Ch. No
I. lacunosa 30
I. triloba complex 30
I. trichocarpa 30
I. gracilis 30
I. tiliacea 60
I. trifida 90
Franklin et al., 1972

10. The genebank from the International Potato Center (CIP)
maintains 1,092 wild sweetpotato accessions
corresponding to 67 species from 19 countries.
The wild collections are conserved as
populations as seed in -20°C cold chambers.

11. The
genus Ipomoea includes
approximately 500–600
species, and sweet
potato is the only
species cultivated in the
genus Ipomoea series B
atatas (Austin 1988).
Thirteen wild species
are considered to be
closely related to
sweet potato.
Of these, I. trifida (H.B.K.)
Don. has been considered
the most likely progenitor
(Nishiyama 1971; Shiotani
and Kawase 1989).

12. Nishiyama considered that sweet potato was derived from the
hexaploid I. trifida, which was generated from the hybridization of
the diploid I. leucantha Jacq. And tetraploid I. littoralis.
Shiotani and Kawase (1989) also hypothesized that the origin of
sweet potato was hexaploid I. trifida, based on the development
of an artificial hybridization of the diploid and tetraploid I.
trifida accessions.
Later, the hypothesis was strongly supported by Munoz-Rodrıguez
et al. (2018) based on gene sequences comparison in
genus Ipomoea

13. BOTANY
Sweet potato is a hexaploid species with 90 somatic chromosomes.
It is a perennial herb with trailing vines and with a cluster of a few medium sized
tubers.
For cultivation purpose, it is treated as an annual with duration of 90 to 120 days.
Though plants produce viable seeds, highly heterozygous nature of the crop results in
a heterogeneous population. Hence stem cuttings are used for propagation purpose.

14. Leaves are simple, alternate and stipulate.
They vary in size and shape, occasionally in
same plant.
Shape varies from ovate to cordate, hastate
or deeply lobed and may change on ageing.

15. Flowers are axillary and borne solitary or in simple cymes.
Flowers are bisexual.
Corolla is attractive and funnel shaped formed by fusion
of five petals.
Anthesis starts before dawn and closes by 9-11 a.m.
Pollination is entomophilies.
Fruit is a capsule with false septa.
Seed coat is hard and impervious to water. Hence,
scarification is required for promoting germination.

16. VARIETIES - TNAU
Co 1, Co 2, Co3, Co CIP 1, Sree
Nandini, Sree Vardhini, Kiran, Sree
Bhadra, Sree Rethna, Gouri and
Sankar are the popular varieties.
Certain local cultivars like SP local,
SP 4, SP 13, SP 18 and Musiri
Thandel are also suited for
cultivation in Tamil Nadu.

17. CO CIP-1

18. CTCRI (Central Tuber Crops Research Institute) Varieties
Varsha A semi-spreading hybrid with reddish purple skin, light yellow flesh and excellent
cooking quality; yield 18-22 t/ha in 120-125 days.
Sree Nandini A spreading variety with light cream skin, white flesh and good cooking quality; yield
20-25 t/ha in 100-105 days
Sree Vardhini A semi-spreading variety with purple skin, light orange flesh and high carotene
content (1200 I.U.); yield 20-25 t/ha in 100-105 days. Tolerant to Feathery mottle
virus.
Sree Ratna A spreading variety with purple skin, orange flesh and excellent cooking quality; yield
20-26 t/ha in 90-105 days
Sree Bhadra A semi-spreading variety with light pink skin and cream flesh; resistant to root knot
nematode; yield 20-27 t/ha on 90-95 days
Sree Arun A spreading variety with pink skin, cream flesh and good cooking quality; yield 20- 28
t/ha in 90-100 days
Sree Varun A spreading variety with cream skin, cream flesh and good cooking quality; yield 20-
28 t/ha in 90-100 days.

19. High β-carotene (14.0 mg/100 g) content as compared to 2.0-3.0 mg/100 g β- carotene in popular
varieties
Tuber yield: 19.8 t/ha
Dry matter: 27.0-29.0%
Starch: 20.0%
Total sugar: 2.0-2.4%
Adaptation: Odisha
Developed by ICAR-Central Tuber Crops Research Institute, Thiruvananthapuram, Kerala
Swee
t

20. High anthocyanin (90.0 mg/100g) content in comparison to popular varieties which have negligible anthocyanin content
Tuber yield: 18.0 t/ha
Dry matter: 24.0-25.5%
Starch: 19.5%
Total sugar: 1.9-2.2%
Salinity stress tolerant
Adaptation: Odisha
Developed by ICAR-Central Tuber Crops Research Institute, Thiruvananthapuram, Kerala

21. Krishna (Purple colour) and Sona (Orange colour)

22. VARIETIES - KAU
The Kerala Agricultural University developed
an improved variety, Kanjangad, yielding
12.39 t/ha.
Purple coloured and spindle shaped tubers
have yellow soft flesh. It is tolerant to shade
and weevil incidence

23. VARIETIES - PUSA
Pusa Safed A white skinned variety with
white flesh
Pusa Sunheri A brown skinned variety with
yellow flesh rich in carotene;
boiled flesh is attractively orange
yellow

24. VARIETIES - ANGRAU
Cross-4 Yield 20-30 t/ha in 90-105 days; highly
susceptible to weevil infestation.
Rajendra Shakarkand-5 Yield 30 t/ha in 105-120 days; resistant
to Fusarium wilt and Cercospora leaf
spot disease.
Kalmegh A short duration variety (90 days)
yielding 26 t/ha.

25. ADVANCES

26. RESEARCH STUDY

27. F1- 100 % RD of NPK (100:60:100 kg/ha),
F2- 50 % RD of NPK + VC (5 t/ha),
F3- 100 % RD of NPK + VC (2.5 t/ha),
F4- 50 % RD of NPK + FYM (15 t/ha) and
F5- 100 % RD of NPK + FYM (7.5 t/ha).

28. • When FYM and vermicompost applied it increased plant growth attributes
due to organic manures not only provided plant nutrients but also improved
the physical condition of soil in respect of granulation friability, porosity and
developed a balanced nutritional environmental to both soil rhizosphere and
plant system.
• The yield of sweet potato is significantly depressed if potassium is missing.
Furthermore, the key factors for increased sweet potato yield are the careful
regulation of N levels and liberal supply of K to increase sink capacity and
photosynthesis
• On the basis of result obtained in the present investigation, it may be
concluded that application of NPK and vermicompost enhanced the growth,
yield and quality of sweet potato. Among these treatments 100% RDF of NPK
+ 2.5 t VC/ha registered higher values of growth, yield and quality of sweet
potato.

29. RESEARCH STUDY

30. • The treatment with 5 kg ha-1 ZnSO4 had significantly higher foliage yield (t ha-1) and
total storage root yield (t ha-1) than the control treatment (0 kg ha-1 ZnSO4 ) over
the two years.
• There were foliage and storage root yield reductions from 10 kg ha-1 application of
ZnSO4.

31. • Application of ZnSO4 fertilizer at 5 kg ha-1 increased the qualities (moisture,
protein, fat, carbohydrate and ash) compared with the control.
• The optimum values of carbohydrate, ash, protein and fat were obtained at 5 kg
ha-1 ZnSO4 fertilizer after which there was a decrease.
• Application of ZnSO4 fertilizer increased moisture content of sweet potato storage
root yields from 0 – 20 kg ha-1.
• There were no significant differences between 5, 10, 15 and 20 kg ha-1 ZnSO4 for
protein.

32. • Application of ZnSO4 fertilizer increased soil
chemical properties (except P), foliage and
storage root yields parameters and proximate
qualities of sweet potato compared with the
control.

33. RESEARCH STUDY

34. Induction of healthy root system from the regenerated shoots is an essential
part for successful development of plantlets.

37. • This study developed an efficient and reproducible regeneration protocol
from the nodal segment explants of I. batatas.
• The explants can be easily obtained from established shoot cultures and
do not require disinfection treatment.
• This protocol will therefore serve as an alternative method for
conventional propagation and further investigations of I. batatas.

38. RESEARCH STUDY

40. • The increase in length & breadth of tuber might be due to increase in
meristematic activity of the apical tissue on GA3 application. Also GA3 was
involved in increasing photosynthetic activity, efficient translocation and
utilization of photosynthates causing rapid cell division, cell elongation and
cell differentiation at growing region of the plant leaves leading to
stimulation of growth.
• The possible reason for Increased in the Girth of tuber is due to crucial role of
GA3 in cell enlargement and cell division, increase in the intercellular space in
peripheral cells of the tuber and higher translocation of photo-assimilates &
mineral nutrients from vegetative parts towards the developing tube that are
extremely active metabolic sink.

41. • Concluded that foliar spray of bio-regulators increase the
Yield and Yield attributes.
• The present investigation revealed that the effective
concentration of undertaken bio-regulators can be used to
improve the yield of sweet potato especially treatment
with GA3 @ 100 ppm & GA3 @ 50 ppm.
• Considering these parameters, it is inferred that GA3 at 100
ppm can be administered with a view for getting maximum
net returns in cultivation of sweet potato

42. RESEARCH STUDY

43. cropping season of
1st (20 July to 20 Nov.) date of
planting,
2nd date of planting (30 July
to 30 Nov.) and
3rd date of planting (9 Aug. to
9 Dec.)
4 varieties were:
V1-Kishan
V2- ST-13
V3- ST-14
V4- Local Check

44. • The interaction revealed that variety Kishan planted on 20 July
produced the highest yield per plant (855.53g) and the highest yield
per hectare (570.36qha-1 ) with a benefit-cost ratio of 4.1 which
was significantly higher than rest other treatments.
• Planting period during the early season registered higher yields
with good quality marketable tubers than the late rainy season
which might be due to the reduction of sunlight hours accompanied
by reduced photosynthetic activities during the late rainy season

45. RESEARCH STUDY

48. • This study evaluated a series of low-cost
postharvest techniques and treatments
which can be employed to reduce sweet
potato storage losses.
• Root tip coppicing in particular can
reduce tip rot incidence; a major cause of
decay losses in sweet potato storage.
• Although a little labour-intensive, this
method when integrated with
dehaulming can significantly prolong
shelf-life.
• In addition, sanitizing roots in
appropriate postharvest chemicals such
as Agrosafe (ai: Azadirachtin, neem seed
oil for organic use) and honey coating
exhibited significant potential for use by
smallholders; with less than 25% decay
losses during 12 weeks of storage.

49. RESEARCH STUDY

51. • Findings suggested that sweet potato could be grown during both kharif and
rabi in acid laterite soils of Orissa.
• Under rabi conditions sweet potato yielded more than kharif with
supplemental irrigation.
• The results also indicated that “Samrat” is highly suitable for both kharif and
rabi seasons, whereas “Sree Nandini” and “Sree Bhadra” only for kharif
season.

52. CULTIVATION PRACTICES

53. SOIL
• The best soil is sandy loam and clay subsoil.
• It can be grown in loamy to clay loam soil.
• Soil should be well drained and soil pH varies
from 5.2 to 6.7
• Heavy clay soil and highly sandy soil are
undesirable.

54. CLIMATE
• It requires moderately warm weather
• Temperature ranges between 21.1 – 26.7℃.
• Temperature < 20℃ was found critical for tuberisation.
• Requires plenty of sunshine and moderate rainfall about 75 to 150 cm.
• High rainfall and long photoperiod promote vine growth and reduces tuber yield.

55. Field Preparation
Plough the
field to fine
tilth.
The soil
depth
should be
atleast 30
cm.
Form ridges
and furrows
at 60 cm
apart.
Sweet
potato can
also be
grown in
beds.

56. Propagation
• Sweet potato are propagated from sprouts or
from slips (vine cuttings), sprouts are peferred.
Sprouts are grown from plant stock selected for
its appearance, freedom from disease and off-
types.
• Approximately 75-100 kg of planting stock sweet
potatoes are needed to produce enough sprouts
to plant 1 hectare.
• Selected tubers are planted at a spacing of 45 x
30 cm and 5-6 cm deep.
• The sprouts are cut after 40-45 days and planted
in secondary nursery. The cuttings 20-30 cm in
length are planted in this nursery at a distance of
60 x 30 cm.
• For 1 ha. Primary nursery 100 m2 and a
secondary nursery of 500 m2 are required.

57. 45 days old sweet potato veins

58. Clip off cuttings in 20-30 cm length after 45 days
from middle

59. SEASON
• June – July for rainfed crop.
• October – November in upland and
• January – February in low lands
under irrigated conditions for
summer crop.

60. Application of fertilizers
Apply 25 t/ha FYM and 90:60:90 kg NPK/ha.
Half of dose nitrogenous fertilizer is applied
as basal dose and half dose 40 days after
planting.

61. Irrigation
Irrigation is done before planting, again on 3rd day
and there after once in a week.
The critical stage of moisture is 40 DAP and earthing
up (35 DAP) may be followed by irrigation.
Stop irrigation one week before harvest.

62. Interculture and weed control
• In early stages of crop growth i.e, up to
2 months after planting, weeds are a
problem to sweet potato.
• 2 manual weedings at 20 and 45 DAP
are sufficient to keep the weeds under
control.
• Earthing up is done at second weeding
to prevent exposure of roots
(particularly during rainly season)
• Fluchloralin @ 1.0 kh/ha in the soil as
pre-planting to control the weeds is
effective.
• Also, application of chloramben @ 3.0
kg.ha at post planting stage control the
weeds.

63. Effect of PGR
• Foliar application of CCC at 250, 500 and 1000 ppm increased the yield.
• Application of ethephon at 250 ppm results in larger number of tubers and
higher yield.
• Foliar application of kinetin at 50 and 100 ppm caused higher tuber yield
of (number, fresh and dry weight).

64. DISEASES

65. Stem rot or wilt
(Fusarium
oxysporum f.
batatus)
Use clean, healthy planting material.
Crop rotation
Resistant varieties
Black rot
(Certocystis
fimbriata)
Use clean healthy planting material.
Dip cutting in 0.2% solution of Aretan or
Agallol before planting.
Cercospora leaf
spot
(Cercospora
bataticola)
3 spraying of 0.25% Dithane M-45 at
fortnight interval is effective
Soil rot
(Streptomyces
ipomea)
Maintain soil pH (5.2)

66. Scurf (Monilochaetes
infuscans)
Good drainage,
Application of sulphur @
300-4—lb/acre to
neutral soils.
Soft rot (Rhizopus
nigricans)
Proper temperature and
RH of 85-90% should be
maintained

67. Sweetpotato Feathery Mottle Virus
(SPFMV)
Aphid-transmitted potyvirus
Sweetpotato Sunken Vein Virus (SPSVV) Whitefly-transmitted closterovirus
Sweetpotato Mild Mottle Virus (SPMMV) Whitefly-transmitted potyvirus
Root-knot nematodes (Meloidogyne spp.) Root-knot nematodes (Meloidogyne spp.)
Root-knot nematodes (Meloidogyne spp.) Root-knot nematodes (Meloidogyne spp.)

68. PESTS

69. Sweet potato
weevil (Cylas
formicarius)
Crop rotation, treatment of
planting material with 0.05%
Monocrotophos, spraying at tri-
weekly interval from one month
after planting.
Sweet potato leaf
eating caterpillar
(Agrius convolvuli)
Collection and destruction of
caterpillar
Ploughing the field after harvest
to expose the pupa
Dusting with 10% carbaryl

70. Stem borers and Feeders
(Synanthedon spp.)
Frequent earthing-up around the
plant base reduces the incidence
of this pes
Sweet potato Bug
(Physomerus grossipes)
Large numbers of bugs are usually
found feeding together, making
handpicking of the bugs or
removal of the infested plants a
feasible means of control.

71. Harvest & Yield
Harvesting is done by digging out tuber with pick-axe when leaves
turn yellow in colour. Tubers are cleaned and packed in gunny bags
for marketing.
Maturity can be ascertained by cutting tuber and the latex from
mature tuber dries up without turning black.
About 20-25 t/ha of tubers in 110 – 120 days can be obtained.

72. Storage
Red skinned varieties store better than white
skinned varieties.
Tubers are stored better at 15oC and 85% RH.
Tubers can also be stored for 2-3 months in a pit
covered with straw.

73. REFERENCE
• Alam, M. K. (2021). A comprehensive review of sweet potato
(Ipomoea batatas [L.] Lam): Revisiting the associated health
benefits. Trends in Food Science & Technology, 115, 512–
529. doi:10.1016/j.tifs.2021.07.001.
• Alam, M. K., Rana, Z. H., & Islam, S. N. (2016). Comparison of the
proximate composition, total carotenoids and total polyphenol
content of nine orange-fleshed sweet potato varieties grown in
Bangladesh. Foods, 5(4), 64. https://doi.org/
10.3390/foods5030064.
• Franklin W. Martin and Alfred Jones (1972). The Species of Ipomoea
Closely Related to the Sweet Potato. Economic Botany, Vol. 26, No.
3: pp. 201-215.

74. • Austin DF (1988) The taxonomy, evolution and genetic diversity of
sweetpotato and related wild species. In: Exploration, maintenance
and utilization of sweet potato genetic resources international
potato center (CIP). Lima, pp 27–60.
• Nishiyama I. Evolution and domestication of the sweet potato. Bot
Maj Tokyo. 1971;84:377–387. doi: 10.15281/jplantres1887.84.377.
• Shiotani I, Kawase T. Genomic structure of the sweet potato and
hexaploids in Ipomoea trifida (H.B.K.) DON. Jpn J
Breed. 1989;39:57–66. doi: 10.1270/jsbbs1951.39.57.
• Munoz-Rodriguez P, Carruthers T, Wood JRI, Williams BRM,
Weitemier K, Kronmiller B, Ellis D, Anglin NL, Longway L, Harris SA,
Rausher MD, Kelly S, Liston A, Scotland RW. Reconciling conflicting
phylogenies in the origin of sweet potato and dispersal to
polynesia. Curr Biol. 2018;28:1246.e1212–1256.e1212.

75. THANK YOU