The aubergine is a vegetable that belongs to the solanaceous or potato family, and which is known scientifically as Solanum melongena.
It is an herbaceous plant although the stems, with their lignified woody tissue tend to make it resemble a small tree or bush. It is cultivated as an annual.
The aubergine plant possesses a very strong deep root system.
The stems are strong, hairy and thorny with a determined growth rate when referring to creeping shoots or an indefinite growth rate when talking about straight, erect stems.
The main stem includes short internodes which fork out into secondary stems, which then divide at the leaf axils.
The leaves are positioned alternately along the stem. They have a long stalk and are large, complete and oval in shape with thorny nerves.
The underneath part of the leaves are covered with a greyish down.
The flowers tend to droop and can appear either by themselves or in clusters of 3 to 5 flowers.
They possess between 5 and 7 green sepals and the same number of elongated violet petals.
The stamens have highly developed anthers which are yellow in colour and are situated under the stigma, which makes direct fertilization difficult.
The fruit is an egg-shaped or bulbous berry which is black, purple, white or white-tinged purple or green with small yellow seeds.
The aubergine requires a warm dry climate which is why it is considered to be one of the most demanding crops with regard to heat.
It is a plant that thrives in high temperatures as long as the relative humidity is at the right level. It will tolerate temperatures as high as 40-45ºC, although the average temperature must be set between 23-25 ºC.
With regard to optimum relative humidity, this will vary between 50% and 65%. A very high relative humidity will encourage the development of air born diseases, and this in turn, will make fertilization difficult.
The aubergine is a plant that needs a lot of sunlight and it will require between 10 and 12 hours daily.
With respect to soil requirements, the aubergine is not particularly demanding, nevertheless, the best soil for growing this crop is deep loamy soil.
Choked roots may be the result if aubergines are cultivated in siliceous soils.
Optimum pH levels for soil vary between pH6 and pH7 although in sandy soils this crop may be grown with pH levels set between pH7 and pH8.5.
The use of acidic soil will cause problems with regard to both the growth and production of this crop.
When considering soil salinity and the water used to irrigate, it must be said that the aubergine is less resistant than the tomato and more resistant than the pepper.