virtual academy for the semi arid tropics lesson 2: growth of groundnut plant course on insect pests...

Virtual Academy for the Semi Arid Tropics

Lesson 2: Growth of Groundnut Plant

Course on Insect Pests of Groundnut

Module I: About Groundnut

After successful completion of this Lesson, you have learned to:

• List the cultivated types of groundnuts.

• Explain the features of the cultivated types of groundnuts.

• Describe growth and development stages of groundnut plants.

• Explain formation of pegs and pods in groundnut.









There are 4 types of groundnut plants based on the growth habit:

• Spanish (bunch),

• Virginia (bunch),

• Virginia (runner) and

• Valencia (bunch) .





In the Spanish (bunch) group, the plants

• grow erect, • possess light-green leaves,• have round, plump non-dormant seeds,

with light-rose testa, • small pods, rarely have more than 2

seeds/pod, • produce pods in clusters at the base of

the plant, and • popularly cultivated type.





In Virginia bunch and runner types,

• the branches crawl either partially or completely on the surface of the soil,

• produce large pods all along them,• possess dark-green foliage,• have oblong, dormant brownish seeds,

and• late maturing but yield higher than

bunch types.





In Valencia bunch types,

• very sparse branching habit, • dark green foliage, • seeds long or short, • seed coats purple, red, russet, or

tan,• many pods may have 3-4 seeds, • are relatively unimportant.





Spanish Bunch type Virginia spreading type

Observe branches and pod setting in the two types





After sowing, seedlings emerge in 5-10 days, depending on sowing depth and soil moisture.





Bunch types do not possess seed dormancy.

But seed of spreading types have a dormant period of 1-6 months, after harvest, depending on temperature and storage conditions.

However, the dormancy can be broken by heat treatment or ethylene treatment.





The plants usually grow slowly until about 40 days after planting.

Peanut plants start flowering about 25 to 40 days after planting (Fig).

Growth is more rapid between 40 to 100 days. During this period a four- to five-fold increase in peanut foliage occurs. Flowering stage





Groundnuts can flower

(orange yellow) over a long period (20-60 days), depending on moisture availability, and temperature.

The flowering period is considerably shorter in bunch type of cultivars than in spreading types.





The flowers are born mostly near the base of plant. It is a self pollinated crop i.e its own pollen fertilizes the ovules.

After fertilization, stalk of ovary elongates and forms a peg which contains fertilized ovules at the tip.

The pegs penetrate the soil up to a depth of 7 cm and then grows horizontally when the ovary starts developing as a pod containing seeds.

Groundnut Pegs





1. Growing ovary.2. Aerial peg, 5 to 7 days.3. Peg soil penetration, 8 to 12 days.4. Beginning of pod enlargement, 14 to 21 days.5. Early stage in pod development.6. Immature pod.

Stages of pod development

(after Smith, 1950)





Normally 60-80 days are required for pod development from flowering to maturation in spreading types and slightly less than that (50-60 days) in bunch types.

Vegetative development declines

During pod filling.

With this, the Lesson 2 on Growth of Groundnut Plant, and also this Module I - About Groundnut concludes.

Next, Module is about economically important insect pests in groundnut crop.

Select Module II from Course contents




virtual academy for the semi arid tropics lesson 2: growth of groundnut plant course on insect pests...

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