3. Introduction
* Dioscorea, yams, is a genus of over 500 species
of usually herbaceous (but sometimes woody)
herbaceous perennial vines that produce starchy,
edible tuberous roots that are an important
source of food in tropical regions worldwide,
including Africa, Asia, Oceania, and Latin America.
The genus belongs to the Dioscoreaceae, the
family that contains true yams.
4. • Dioscorea species are climbing; roots
tuberous; tubers large; stem leafy
• The stem is a smooth green twiner, about the
size of a goose-quill, twining from the right to
the left, over fences, bushes, etc.
• The leaves are symmetrical and heart-shaped,
gradually tapering to a sharp, acuminate point,
(taper )and are borne on leaf stalks from 2 to 4
inches long.
5.
6. Geographical distribution
• D. deltoidea is found growing in north
western Himalayas from Kashmir and
Punjab to Nepal and china upto an altitude
of 1000 to 3000m. It is cultivated in
Jammu and Kashmir and in part of
Himachal Pradesh. D. Deltoidea is also
found in USA and Mexico.
7.
8. Uses
• Its tuber roots are used in Ayurvedic medicine,
roots are used for the preparation of nutritive
tonic used in general sexual weakness.
• The juice of the root tuber is taken in the
evening in the treatment of roundworm.
• Weak bones.
• Gallbladder problems.
• Infertility.
• Menstrual disorder.
• PMS(Premenstrual syndrome).
9. • Anti-spasmodic, anti-inflammatory, anti-
rheumatic, diaphoretic (Inducing perspiration),
diuretic, GI tonic, expectorant.
• Paste of rhizomes is also applied in hair to kill lice
and allergic states.
• The powder from the rhizomes of the plant is
taken orally to cures dysentery, abdominal pains
and piles.
10. Chemical constituents
• Steroidal saponin glycosides: dioscin and its
aglycone is diosgenin. Small quantity of
hecogenin.
• Resin-botagenin.
• Alkaloids:dioscorine.
• Sterol: cholesterol, stigmasterol, P-sitosterol.
• Enzyme: sapogenase.
11. Climate and soil
• A sub tropical or sub temperate and humid
climate with distinct two to three month of cold
winter is ideal for the growth of the plant.
• Sandy loam soil is most suitable for its cultivation
and better yield of corm.
• The species prefers a more or less neutral soil
pH(6.8-7.2) for optimum growth of the tubers.
13. Propagation material
• The species can be easily propagated by
underground corms or aerial bulbs. Vegetatively
propagated plants have relatively faster growth
than seedlings.
• Larger bulbs that are more than 4cm in diameter.
• November and December are the ideal months
for collection of bulbs for propagation.
• Bulb are buried in soil for protection and used as
propagules for next season.
14.
15. Nursery technique
Raising propagules : -
• Direct planting of the corms or bulb in the field is more
effective than transplanting nursery-raised seedlings,
hence it is the preferred method.
• The suitable time for planting corms or bulb April–May in
mid-hills.
• For raising seedlings, seeds are separated from mature
fruits collected in November and are sown in spring or
early summer.
• Germination takes about 15–30 days and is less than 40%
even under laboratory conditions.
16. • Propagule rate and pretreatment :
• About 80–100 kg well-developed bulb or corms are
required for plantation on 1 hectare of land at a spacing
of 50 cm × 50 cm.
• No pretreatment is required before sowing the bulbils
17. Planting in the fields
Land preparation and fertilizer application :
• The planting beds should be tilled properly and made
weed-free, and the soil should be well pulverized.
• Apply FYM @ 25 t/ha at the time of last ploughing.
Follow fertilizer schedule of 40:60:120 kg NPK/ha.
Planting and optimum spacing :
• Plant-to-plant spacing of 50 cm × 50 cm is considered
optimum for good growth and yield.
• This spacing gives an optimum crop stand of 25q plant
material per hectare.
18. • Plant spacing of 100 cm × 100 cm yields higher number
of bulbils per plant; however, the average weight of
bulbils as well as their number per unit area are much
higher at the spacing of 50 cm × 50 cm.
Intercropping system :
• The plant is preferred as a solo crop, but needs staking
support or host of shrubs and trees.
Interculture and maintenance practices :
• Applying organic manure @ 15–20 tonnes/ hectare at
the time of planting enhances average weight and yield
of bulbils.
• Where sufficient FYM/organic manure is not available,
suitable doses of inorganic fertilizers can be given to
compensate for FYM for higher yield.
19. • The twiner needs staking support to expose maximum
foliage area to the sunlight.
• The plants may be supported by a system of bamboo
pillars and string or wooden stakes or trellis.
Irrigation practices :
• Only light irrigation to maintain humidity during dry
season is recommended through sprinklers.
• Flood irrigation may result in waterlogging and should be
avoided.
Weed control :
• Manual weeding at monthly intervals during the peak
period of weed growth (July–September) controls weeds
to a great extent.
Disease and pest control :
• No serious disease or infestation has been reported in
this crop.
20. Harvest management
Crop maturity and harvesting :
• Bulbils become ready for harvest within 180–200 days
from sprouting.
• The mother corm may be harvested after two to three
years. The crop undergoes dormancy during winter.
• Hence, October–November are the ideal months to
harvest bulbils/ underground corms.
• In subtropical and tropical areas, mid-September to mid-
October is the most suitable time.
• The bulbils should be plucked as and when they become
fully grown, otherwise they are shed before the foliage
develops.
21. Post-harvest management :
• The corms and bulbils can be stored in gunny or paper
bags without causing any adverse effect on the rate of
sprouting.
• There might be delay in sprouting of the bulbils by about
two days.
Yield :
• The crop yields an average of 12 tonnes of fresh corms
per hectare in the second year.
22. Economic of cultivation
• Planting material 25q/ha 100/Kg. 2,50,000
• FYM 25 tonnes 500Rs/tons 12,500
• Land preparation
And ploughing 3,750
• Bed preparation 5,000
• Fertilizer, spray & other nutrients 5,000
• Green manure & mulching 12,500
• Weeding & hoeing Twice 7,500
• Irrigation 10,000
• Sowing 5000
5,000
• Uprooting and Washing 12,500
• Miscellaneous 10,000
• TOTAL EXPENSES 6,17,250
• Total yield 120q 20,000rs/q 24,00,000
PARTICULARS QTY. RATE(Rs.) TOTAL(Rs.)