Great STEEMIANS!!! This is to say good morning to you all. I am here again to discuss about onion with you. This time around, I shall be writing about the agriculture of Onion. This includes;

• Introduction
• cultivation of Onion
• propagation method of Onion
• Major diseases affecting Onion.

INTRODUCTION

The onion is one of the most important commercial vegetable crops grown in India: The demand for onion is worldwide. It is used both in raw and mature bulb stage as vegetable and spices. The pungency in onion is due to a volatile oil known as ally-proopyldisulphide. The bulb of onion consists of swollen bases of green foliage leaves and fleshy scales. Maharashtra, Tamil Nadu, A.P., Bihar and Punjab are the important onion producing states.

CULTIVATION OF ONION

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Planting chosen a sheltered,sunny site and avoid ground on which onions have been grown in the last three years. Fertile ground which has been manured,but not freshly for example manured in the autumn/early winter before a spring planting- is ideal. Lime if your soil is acidic. Autumn planting onion set can be put in at any time between September and November, as long as weather and soil conditions are suitable, buy for largest bulbs and in cold areas, it is best to plant as soon as soil can be made ready. Do not grow any of these bulbs on land that may become waterlogged in winter. Spring planting Onion sets can go in at any time between early March and mid April, when the ground is not frozen or too wet, but heat-treated sets should not be planted until early April.
Onions in rows 25cm (10inches) apart. For medium sized onions, space the sets 10cm (4inches) apart in the row; a wider spacing of 15cm(6inches) will give larger bulbs. On a "bed system" ,space onions 15cm (6inches) apart each way.

PROPAGATION METHODS OF ONOIN

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Onions can be established one or two ways;

• direct seedings
• sets, and transplants.

direct seedings

Direct seedings give excellent results where the season is sufficiently long enough to provide the early prebulbing growth needed before bolting and is the preferred system for most acreages in the US.
Direct seeding planting rates are at depths of 1/4 to 3/4 of an inch with space from 1" to 3" depending on the product being produced. There are approximately 9500 seeds per ounce, and with good germination, 3 to 4 pounds of seed per acre are required for a good stand. Rows should be 18" to 26" apart.

set and transplant

These are used in areas where the season is not long enough for proper bulb development. The use of this method ensures large bulb sizes and uniform maturity dates. Sets arebsmall dry bulbs that are produces in the previous season by overseeding and growing under conditions that promote rapid bulbing. Transplanting are grown in the south and have three to five leafs at the time of transplanting. The leafs are pruned prior to field planting to facilitate the handling and to harden off the plants.

MAJOR DISEASES AFFECTING ONIONS

Fungal diseases affecting root and underground plant parts in which Allium species especially Onion includes;

• Pink Root
  Pink root caused by the fungus phomaterrestris,is the most common and damaging root diseases of onion in Georgia symptom yellowing root.

• Fasarium Basar Root

Fasarium basar root is caused by the fungus fasarium oxysporum- symptom yellowing leaf tips that later become necrotic.

• Botrytis Neck Root

The fungus causing neck root, botrytis allii can survive in the soil or on rotting bulbs assclerobia, symptom leaf distortion.

• Botrytis Leaf Bright

It is caused by Botrytis squamosa. Thus fungus infects onion foliage

• Purple Blotch
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  Purple

It is by alternaria porri

• Stem Phylum Leaf Bright

Caused by the fungus by stem phylum vasacarium

• Downy Mildew

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Caused by the fungus peronospora destructor.

On this note, I shall proceed to second part next time. Thank you all for reading.
Once again, don't forget to follow,upvote and comment on this post. I shall greatly appreciate this.
Great STEEMIANS !!!!
God bless you all. Amen