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Dioscorea
Botanical Name -Dioscorea alata L.
Family - Dioscoreaceae

Peruvalli (D.alata) , CO 1, Sree Roopa, Sree Keerthi, Sree Shilpa.
Siruvalli (D.esculenta) : Sree Latha, Sree Kala.

Soil –

It requires warm and humid conditions with a mean temperature of 300C and a well
distributed annual rainfall of 1200-2000 mm. Sandy loam soil with a pH of 6.0 to 6.5 is preferred with good drainage and cool weather.

Climate – 

It can be grown in tropical and sub-tropical climatic conditions upto 1500m above mean sea level. 

March – June

Use mature tubers or pieces of 250-300 g tubers taken from the previous crop as seed material at the rate of 1875 – 2500 kg/ha. Mini setts of 25 g are recommended for planting directly in the field or raising a nursery and planting plants after 60 days.
Medium sized tuber of 100-150 g is sufficient. Planting is done in beds or in ridges or in mounds or in rows 75 cm apart either way.
Plough the field to a fine tilth and form ridges and furrows at 75 cm spacing for raising lesser yam. Ridges and furrows at 75 cm spacing or pits of 45 x 45 x 45 cm for planting greater yam at 90 x 90 cm. Fill the pits with top soil and FYM.

To plant greater yam, 3,000-3,700 kg

and for lesser yam 1800-2700kg of seed material is required.

Copious watering once in a week is necessary.

Apply FYM @ 25 t/ha at the time of last ploughing. Follow fertilizer schedule of
40:60:120 kg NPK/ha as basal and 4 kg/ha of Azospirillum (mixed with 40 kg of soil) 30 days after planting.

Apply 50 kg N and 120 kg K/ha 90 days after planting. Go for weeding before
top dressing, followed by earthing up.

The vines should be trained on bamboo poles. Weeding has to be done as and when necessary. It can be intercropped profitably in coconut, arecanut, rubber, banana and robusta coffee plantations at a spacing of 90 x 90 cm. In Robusta banana + Dioscorea system, banana should be manured at the full recommended dosage and for yams, manuring at the 2/3rd recommended level is sufficient.

Trailing is necessary to expose the leaves to sunlight. It is done within 15 days after sprouting by coir rope attached to artificial supports in the open area or to the trees where it is raised as an intercrop.

Yam scale is found to occur on the tubers both under field and storage conditions.
Use scale free seed tuber for planting.

Greater yam and white yam become ready for harvest by 9-10 months after planting.
Lesser yam takes 8-9 months for attaining maturity. Carefully dig out the tubers without causing injury.

20 – 25 t/ha in 240 days.