Under-utilized crop (Amaranthus): Uses, origin, cultivars, cultivation,harvesting & seed production

Introduction:

Amaranthus is leafy vegetable grown commonly in Terai region of Nepal. High yield per unit of area & high nutritional value are beautiful characteristics of this crop. Amaranthus blitum & Amaranthus tricolor are most common species commonly grown in Nepal & world.

This crop is very popular due to high vitamin A content along with vitamin C, protein & minerals too. Young & tender leaves are eaten as cooked vegetables.

Origin:

Amaranthus is originated from India. (Thompson & Kelly, 1957)

Varieties:

The commonly available & recommended varieties are:

1. Coimbotire-1 (Co-1) – Amaranthus dubium: This variety was released from Tmil Nadu University, India. It is usually grown for its green leaves as well as mature stem. Seeds are small and black, tolerates pests & diseases.
2. Coimbotire-2 (Co-2) – Amaranthus tricolor (Badi chauli): Stem is thick green, large leaves, green colored and suitable for summer crops. It responds well to cuttings.
3. Coimbotire-3 (Co-3)
4. Coimbotire-5 (Co-5)
5. Pusa kiran
6. Pusa Kirti
7. Pusa lal
8. Chaulai

Climate:

Amaranthus are influenced much by day length & responds differently to the change in photo & thermo-periodism. It is warm season crop and can be cultivated from Terai to Mid-Hills with adjustment of planting time. It is susceptible to frost and requires hot & humid climate.

Soil & field preparation:

It can be grown in wide range of soils but sandy loam soil with slightly acidic pH is better for growth & development. Well drained, fertile & rich in organic matter sort of soil is best suited for this crop. The soil pH should be 5.5-7.5 for better crop & for this 3-4 ploughing followed by planking is necessary for good tilth.

Manuring & fertilizer:

Incorporate 20 tons of well decomposed FYM or compost during field preparation. Inorganic fertilizers of 50: 30: 20 kg NPK/ha is recommended where P & K are applied as basal dose where N is applied in 3 split doses. Initially at 20 days after sowing, 2^nd & 3^rd after second & third cuttings.

Sowing:

Amaranthus can be grown in different season according to geographical locations.

Sowing methods:

1. Direct sowing of seed in the field in the rows or broadcasting.
2. Raising of seedlings and then transplanting in the main field.
3. Since seeds are very small, these should be sown very carefully.

Seed rate:

2-2.5 kg/ha is sufficient for direct sowing method & 1-1.5 kg/ha for transplanting.

Spacing:

Recommended spacing is 20 cm * 15 cm (row to row * plant to plant) is maintained in the field for easy intercultural operations. Sowing should be 1 cm deep with adequate moisture.

Irrigation & Inter-cultural operations:

Light irrigation followed by sowing of seed for germination of seed. It requires adequate water for growth & higher yield during summer irrigation is given at 3-5 days interval. 2-3 weeding are essential.  

Harvesting & yield:

Clipping starts from 25-30 days of seed sowing & continues until 60 days at an interval of 7-10 days.

Yield depends upon the type of cultivar, management practices, followed and growing seasons. Yield vary from 20-30 tons/ha.

Storage:

Since it is leafy vegetables, its storage is a problem and it cannot be stored for long time under ordinary condition. But they can be stored for 10-14 days at 0 degree Celsius with 90-95% RH. Well dried leaves of Amaranthus can be stored for 1 year. Pre-harvest spray of Benzoic acid at 5-10 ppm helps Amaranthus to retain fresh green color for an additional 3-5 days.

Seed production:

Amaranthus is cross-pollinated crop, which requires isolation distance of about 400 m between two cultivars. It is quick growing crops & forms seed in about 10-12 weeks. After taking a number of leaf cuttings, only a few last cuttings can be omitted to produce seeds. After harvesting, initial drying of spikes can be done in sun and drying the seeds to a 15% moisture content are usually practiced so that the seeds can be threshed with pliable bamboo sticks. Seed yield is about 200 kg/ha.

Crop protection:

Diseases:

Mosaic of broad leaf mustard:

1. Use disease free seeds for planting.
2. Use insecticide for controlling aphids.

Alternaria leaf spot of broad leaf mustard & spinach:

1. Long crop rotation
2. Spraying of crop with fungicides (Dithane Z-78 0.25% or Blitox-50 @ 0.3%) is recommended.

Leaf spot disease:

1. Spray Blitox @ 0.2% or Bordeaux mixture @ 1% at 15 days interval.

Downy mildew:

1. Follow crop rotation.
2. Remove crop debris of previous crops.

White rust:

1. Adopt proper crop rotation.
2. Spraying of crop with fungicides (Dithane Z-78 0.25% or Blitox-50 @ 0.3%) is recommended for asparagus.

Insects pests:

1. Aphids
2. Leaf eating caterpillar : they are the major insect pest affecting asparagus plant.

Source Book: Vegetable production technology