Groundnut, ‘the unpredictable legume’ is also known as earthnut, peanut, monkey nut and manilla nut. It is the 13th most important food crop and 4th most important oilseed crop of the world. The botanical name Arachis hypogaea L. has been derived from the Greek words, Arachis meaning a legume and hypogaea meaning below ground referring to geocarpic nature of pod formation.
Groundnut kernels have about 25% protein which is 1.3 times higher than meat, 2.5 times higher than eggs and 8 times higher than fruit. The oil content in kernels ranges from 40-50% and is extensively used for cooking (culinary oil) and for preparing vegetable oil (vanaspati). Its oil is also used for the preparation of soaps, cosmetics, cold cream and for various industrial uses.
Its oil is now used in pharmaceutical as a substitute to oleic oil. The groundnut is dug, extracted, processed, and consumed as a snack food, peanut butter, and a candy. Groundnut kernels are consumed directly as raw, roasted, boiled or fried. Groundnut haulms is a very good palatable (8-11% protein) fodder for cattle, when fed in green state. The groundnut cake have immense value as feeding material for livestock and organic manure. It contains 8% N, 1.4% P2O5 and 1.2% K2O.
The groundnut cake powder is used as laundry starch and in the manufacture of paper, gummed tapes and plastics. Groundnut shell is used as fuel and for manufacture of coarse boards, cork substitute and activated carbon. Groundnut shell is rich in potassium (1.5%) and calcium (3%), hence can be used as organic manure.
These multiple uses of groundnut plants makes it an excellent cash crop for domestic markets as well as for foreign trade in several developing and developed countries. Globally, 50% of the groundnut produced is used for oil extraction, 37% for confectionery use and 12% for seed purpose.
Groundnut being a leguminous crop, it has following advantages over other crops:
1. Being leguminous, groundnut has the ability to fix atmospheric nitrogen biologically into the soil which enriches the soil and this benefits the succeeding crop in rotation.
2. It is one crop which does not require much irrigation and can be cultivated on the residual soil moisture conditions.
3. It can provide gainful employment during the lean season.
4. Unlike the vegetables and fruits, which are highly perishable items, groundnuts can be stored for a long period of time and sold when prices are high.
5. It provides a very nutritive green fodder (haulms) and feed (oil cake) which can be fed to cattle and also used as organic manures.
6. Groundnut crop is considered not only as an oilseed crop but also as a food crop because its kernels are rich in protein contents and vitamins.
2. Origin and History of Groundnut:
Cultivated groundnut originates from South America. The Arachis genus was distributed in Argentina, Bolivia, Brazil, Paraguay and Uruguay with largest number of species reported from Brazil followed by Bolivia. Arachis hypogaea is believed to have originated in North Argentina and Southern Bolivia, where the diploid wild (progenitors of groundnut) species (A. batizocoi Krapov & W.C. Gregory Morten nudum and A. duranensis Krapov & W.C. Gregory nov. sp.) that are closely related to tetraploid A. hypogaea and A. monticola Krapov & Rigoni are distributed in this region.
This suggests that this region is the primary center of diversity. The secondary center of diversity includes Guarani region of Paraguay-Parana, Goias and Mina Gerais region of Tocatins, San Fransisco, Rondonia North-West Mato Grosso of Brazil, eastern foothills of the Andes and Bolivia and Peru’s upper Amazon and West Coast.
North East Brazil is considered as tertiary center of Diversity. The credit for the introduction of the groundnut into India belongs to the Jesuit Fathers who followed Vasco De Gama shortly after his first landing in India.
The flora of Western India includes a large number of specimens of South and Central American origin, introduced by missionaries. The so-called ‘indigenous’ variety in modern India was likely of Brazilian origin. Since South America was discovered in early 1500 A.D., it is probable that the plant was introduced into India at the earliest by the first half of the sixteenth century.
3. Botanical Description of Groundnut:
The groundnut is a low growing annual plant. The groundnut plant has prostrated to upright stems that sometimes reach a height of 46 cm. The plant usually grows slowly until about 40 days after planting. Plants start flowering about 25-40 days after planting. Growth is more rapid between 40-100 days. During this period 4-5 fold increase in peanut foliage occurs.
After sowing seedling emerge in 5-10 days, depending on sowing depth and soil moisture. Bunch type does 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.
Root:
The groundnut has a tap root with its laterals covering a depth of 35-40 cm and spread of 30-35 cm of radius.
Stem:
The groundnut stem is cylindrical, hairy and becomes more or less angular with age. The central stem is usually taller and has a few laterals which form main basis for classification of different varieties and forms.
Leaves:
The groundnut has a pinnately compound leaf with two pairs of leaflets. There is a pair of stipules about 4 cm long with long alternate points which are fused with the petiole for about 1 half of their length. The leaves occur alternatively 1 at each node. The shape of leaflets varies from elliptic, ovate to oblong with the entire or ciliate margins, subcardate base and obtuse or shortly mucronate tip.
Flowers:
Groundnut can flower (orange yellow in colour) over a long period depending on moisture availability, and temperature. Usually flowering takes place between 24-30 days after sowing and is little earlier in bunch than in spreading types. The flowering period normally
lasts for 3-8 weeks in case of bunch type and 6-10 weeks in case of spreading type. Three to five flowers are produced in the axils of leaves (near the base of the plant) on reproductive branches.
Groundnut is a completely self-pollinated crop i.e. its own pollen fertilizes the ovule. It is a unique plant because after pollination, the ovary elongates to produce a peg (gynophore, which contains fertilized ovules at the tip) that buries the ovary into the soil.
The peg is positively geotropic i.e., it grows towards the soil and penetrates into the soil. The peg penetrates the soil up to a depth of 7-8 cm. The ovary starts developing into a fruit (pod) after taking a horizontal position in the soil.
The pods are formed within 5-7 cm depth of surface soil and this is known as fruiting zone or pod zone. The pegs that are formed 15 cm above the soil surface usually fail to contact the soil and these will wither and hence their fertilized ovaries abort.
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. Bunch type takes 85-100 days to mature and spreading cultivars mature in 110-130 days under warm conditions.
The mature fruit may normally contain upto 4 seeds depending on variety. Single seeded pods may be produced when all ovules but the proximal abort. Seedless fruits called ‘pops’ may be produced when calcium is limiting.
Groundnut, ‘the unpredictable legume’ is also known as earthnut, peanut, monkey nut and manilla nut. It is the 13th most important food crop and 4th most important oilseed crop of the world. The botanical name Arachis hypogaea L. has been derived from the Greek words, Arachis meaning a legume and hypogaea meaning below ground referring to geocarpic nature of pod formation.
Groundnut kernels have about 25% protein which is 1.3 times higher than meat, 2.5 times higher than eggs and 8 times higher than fruit. The oil content in kernels ranges from 40-50% and is extensively used for cooking (culinary oil) and for preparing vegetable oil (vanaspati). Its oil is also used for the preparation of soaps, cosmetics, cold cream and for various industrial uses.
Its oil is now used in pharmaceutical as a substitute to oleic oil. The groundnut is dug, extracted, processed, and consumed as a snack food, peanut butter, and a candy. Groundnut kernels are consumed directly as raw, roasted, boiled or fried. Groundnut haulms is a very good palatable (8-11% protein) fodder for cattle, when fed in green state. The groundnut cake have immense value as feeding material for livestock and organic manure. It contains 8% N, 1.4% P2O5 and 1.2% K2O.
The groundnut cake powder is used as laundry starch and in the manufacture of paper, gummed tapes and plastics. Groundnut shell is used as fuel and for manufacture of coarse boards, cork substitute and activated carbon. Groundnut shell is rich in potassium (1.5%) and calcium (3%), hence can be used as organic manure.
These multiple uses of groundnut plants makes it an excellent cash crop for domestic markets as well as for foreign trade in several developing and developed countries. Globally, 50% of the groundnut produced is used for oil extraction, 37% for confectionery use and 12% for seed purpose.
Groundnut being a leguminous crop, it has following advantages over other crops:
1. Being leguminous, groundnut has the ability to fix atmospheric nitrogen biologically into the soil which enriches the soil and this benefits the succeeding crop in rotation.
2. It is one crop which does not require much irrigation and can be cultivated on the residual soil moisture conditions.
3. It can provide gainful employment during the lean season.
4. Unlike the vegetables and fruits, which are highly perishable items, groundnuts can be stored for a long period of time and sold when prices are high.
5. It provides a very nutritive green fodder (haulms) and feed (oil cake) which can be fed to cattle and also used as organic manures.
6. Groundnut crop is considered not only as an oilseed crop but also as a food crop because its kernels are rich in protein contents and vitamins.
2. Origin and History of Groundnut:
Cultivated groundnut originates from South America. The Arachis genus was distributed in Argentina, Bolivia, Brazil, Paraguay and Uruguay with largest number of species reported from Brazil followed by Bolivia. Arachis hypogaea is believed to have originated in North Argentina and Southern Bolivia, where the diploid wild (progenitors of groundnut) species (A. batizocoi Krapov & W.C. Gregory Morten nudum and A. duranensis Krapov & W.C. Gregory nov. sp.) that are closely related to tetraploid A. hypogaea and A. monticola Krapov & Rigoni are distributed in this region.
This suggests that this region is the primary center of diversity. The secondary center of diversity includes Guarani region of Paraguay-Parana, Goias and Mina Gerais region of Tocatins, San Fransisco, Rondonia North-West Mato Grosso of Brazil, eastern foothills of the Andes and Bolivia and Peru’s upper Amazon and West Coast.
North East Brazil is considered as tertiary center of Diversity. The credit for the introduction of the groundnut into India belongs to the Jesuit Fathers who followed Vasco De Gama shortly after his first landing in India.
The flora of Western India includes a large number of specimens of South and Central American origin, introduced by missionaries. The so-called ‘indigenous’ variety in modern India was likely of Brazilian origin. Since South America was discovered in early 1500 A.D., it is probable that the plant was introduced into India at the earliest by the first half of the sixteenth century.
3. Botanical Description of Groundnut:
The groundnut is a low growing annual plant. The groundnut plant has prostrated to upright stems that sometimes reach a height of 46 cm. The plant usually grows slowly until about 40 days after planting. Plants start flowering about 25-40 days after planting. Growth is more rapid between 40-100 days. During this period 4-5 fold increase in peanut foliage occurs.
After sowing seedling emerge in 5-10 days, depending on sowing depth and soil moisture. Bunch type does 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.
Root:
The groundnut has a tap root with its laterals covering a depth of 35-40 cm and spread of 30-35 cm of radius.
Stem:
The groundnut stem is cylindrical, hairy and becomes more or less angular with age. The central stem is usually taller and has a few laterals which form main basis for classification of different varieties and forms.
Leaves:
The groundnut has a pinnately compound leaf with two pairs of leaflets. There is a pair of stipules about 4 cm long with long alternate points which are fused with the petiole for about 1 half of their length. The leaves occur alternatively 1 at each node. The shape of leaflets varies from elliptic, ovate to oblong with the entire or ciliate margins, subcardate base and obtuse or shortly mucronate tip.
Flowers:
Groundnut can flower (orange yellow in colour) over a long period depending on moisture availability, and temperature. Usually flowering takes place between 24-30 days after sowing and is little earlier in bunch than in spreading types. The flowering period normally
lasts for 3-8 weeks in case of bunch type and 6-10 weeks in case of spreading type. Three to five flowers are produced in the axils of leaves (near the base of the plant) on reproductive branches.
Groundnut is a completely self-pollinated crop i.e. its own pollen fertilizes the ovule. It is a unique plant because after pollination, the ovary elongates to produce a peg (gynophore, which contains fertilized ovules at the tip) that buries the ovary into the soil.
The peg is positively geotropic i.e., it grows towards the soil and penetrates into the soil. The peg penetrates the soil up to a depth of 7-8 cm. The ovary starts developing into a fruit (pod) after taking a horizontal position in the soil.
The pods are formed within 5-7 cm depth of surface soil and this is known as fruiting zone or pod zone. The pegs that are formed 15 cm above the soil surface usually fail to contact the soil and these will wither and hence their fertilized ovaries abort.
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. Bunch type takes 85-100 days to mature and spreading cultivars mature in 110-130 days under warm conditions.
The mature fruit may normally contain upto 4 seeds depending on variety. Single seeded pods may be produced when all ovules but the proximal abort. Seedless fruits called ‘pops’ may be produced when calcium is limiting.
Groundnut, ‘the unpredictable legume’ is also known as earthnut, peanut, monkey nut and manilla nut. It is the 13th most important food crop and 4th most important oilseed crop of the world. The botanical name Arachis hypogaea L. has been derived from the Greek words, Arachis meaning a legume and hypogaea meaning below ground referring to geocarpic nature of pod formation.
Groundnut kernels have about 25% protein which is 1.3 times higher than meat, 2.5 times higher than eggs and 8 times higher than fruit. The oil content in kernels ranges from 40-50% and is extensively used for cooking (culinary oil) and for preparing vegetable oil (vanaspati). Its oil is also used for the preparation of soaps, cosmetics, cold cream and for various industrial uses.
Its oil is now used in pharmaceutical as a substitute to oleic oil. The groundnut is dug, extracted, processed, and consumed as a snack food, peanut butter, and a candy. Groundnut kernels are consumed directly as raw, roasted, boiled or fried. Groundnut haulms is a very good palatable (8-11% protein) fodder for cattle, when fed in green state. The groundnut cake have immense value as feeding material for livestock and organic manure. It contains 8% N, 1.4% P2O5 and 1.2% K2O.
The groundnut cake powder is used as laundry starch and in the manufacture of paper, gummed tapes and plastics. Groundnut shell is used as fuel and for manufacture of coarse boards, cork substitute and activated carbon. Groundnut shell is rich in potassium (1.5%) and calcium (3%), hence can be used as organic manure.
These multiple uses of groundnut plants makes it an excellent cash crop for domestic markets as well as for foreign trade in several developing and developed countries. Globally, 50% of the groundnut produced is used for oil extraction, 37% for confectionery use and 12% for seed purpose.
Groundnut being a leguminous crop, it has following advantages over other crops:
1. Being leguminous, groundnut has the ability to fix atmospheric nitrogen biologically into the soil which enriches the soil and this benefits the succeeding crop in rotation.
2. It is one crop which does not require much irrigation and can be cultivated on the residual soil moisture conditions.
3. It can provide gainful employment during the lean season.
4. Unlike the vegetables and fruits, which are highly perishable items, groundnuts can be stored for a long period of time and sold when prices are high.
5. It provides a very nutritive green fodder (haulms) and feed (oil cake) which can be fed to cattle and also used as organic manures.
6. Groundnut crop is considered not only as an oilseed crop but also as a food crop because its kernels are rich in protein contents and vitamins.
2. Origin and History of Groundnut:
Cultivated groundnut originates from South America. The Arachis genus was distributed in Argentina, Bolivia, Brazil, Paraguay and Uruguay with largest number of species reported from Brazil followed by Bolivia. Arachis hypogaea is believed to have originated in North Argentina and Southern Bolivia, where the diploid wild (progenitors of groundnut) species (A. batizocoi Krapov & W.C. Gregory Morten nudum and A. duranensis Krapov & W.C. Gregory nov. sp.) that are closely related to tetraploid A. hypogaea and A. monticola Krapov & Rigoni are distributed in this region.
This suggests that this region is the primary center of diversity. The secondary center of diversity includes Guarani region of Paraguay-Parana, Goias and Mina Gerais region of Tocatins, San Fransisco, Rondonia North-West Mato Grosso of Brazil, eastern foothills of the Andes and Bolivia and Peru’s upper Amazon and West Coast.
North East Brazil is considered as tertiary center of Diversity. The credit for the introduction of the groundnut into India belongs to the Jesuit Fathers who followed Vasco De Gama shortly after his first landing in India.
The flora of Western India includes a large number of specimens of South and Central American origin, introduced by missionaries. The so-called ‘indigenous’ variety in modern India was likely of Brazilian origin. Since South America was discovered in early 1500 A.D., it is probable that the plant was introduced into India at the earliest by the first half of the sixteenth century.
3. Botanical Description of Groundnut:
The groundnut is a low growing annual plant. The groundnut plant has prostrated to upright stems that sometimes reach a height of 46 cm. The plant usually grows slowly until about 40 days after planting. Plants start flowering about 25-40 days after planting. Growth is more rapid between 40-100 days. During this period 4-5 fold increase in peanut foliage occurs.
After sowing seedling emerge in 5-10 days, depending on sowing depth and soil moisture. Bunch type does 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.
Root:
The groundnut has a tap root with its laterals covering a depth of 35-40 cm and spread of 30-35 cm of radius.
Stem:
The groundnut stem is cylindrical, hairy and becomes more or less angular with age. The central stem is usually taller and has a few laterals which form main basis for classification of different varieties and forms.
Leaves:
The groundnut has a pinnately compound leaf with two pairs of leaflets. There is a pair of stipules about 4 cm long with long alternate points which are fused with the petiole for about 1 half of their length. The leaves occur alternatively 1 at each node. The shape of leaflets varies from elliptic, ovate to oblong with the entire or ciliate margins, subcardate base and obtuse or shortly mucronate tip.
Flowers:
Groundnut can flower (orange yellow in colour) over a long period depending on moisture availability, and temperature. Usually flowering takes place between 24-30 days after sowing and is little earlier in bunch than in spreading types. The flowering period normally
lasts for 3-8 weeks in case of bunch type and 6-10 weeks in case of spreading type. Three to five flowers are produced in the axils of leaves (near the base of the plant) on reproductive branches.
Groundnut is a completely self-pollinated crop i.e. its own pollen fertilizes the ovule. It is a unique plant because after pollination, the ovary elongates to produce a peg (gynophore, which contains fertilized ovules at the tip) that buries the ovary into the soil.
The peg is positively geotropic i.e., it grows towards the soil and penetrates into the soil. The peg penetrates the soil up to a depth of 7-8 cm. The ovary starts developing into a fruit (pod) after taking a horizontal position in the soil.
The pods are formed within 5-7 cm depth of surface soil and this is known as fruiting zone or pod zone. The pegs that are formed 15 cm above the soil surface usually fail to contact the soil and these will wither and hence their fertilized ovaries abort.
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. Bunch type takes 85-100 days to mature and spreading cultivars mature in 110-130 days under warm conditions.
The mature fruit may normally contain upto 4 seeds depending on variety. Single seeded pods may be produced when all ovules but the proximal abort. Seedless fruits called ‘pops’ may be produced when calcium is limiting.
Groundnut, ‘the unpredictable legume’ is also known as earthnut, peanut, monkey nut and manilla nut. It is the 13th most important food crop and 4th most important oilseed crop of the world. The botanical name Arachis hypogaea L. has been derived from the Greek words, Arachis meaning a legume and hypogaea meaning below ground referring to geocarpic nature of pod formation.
Groundnut kernels have about 25% protein which is 1.3 times higher than meat, 2.5 times higher than eggs and 8 times higher than fruit. The oil content in kernels ranges from 40-50% and is extensively used for cooking (culinary oil) and for preparing vegetable oil (vanaspati). Its oil is also used for the preparation of soaps, cosmetics, cold cream and for various industrial uses.
Its oil is now used in pharmaceutical as a substitute to oleic oil. The groundnut is dug, extracted, processed, and consumed as a snack food, peanut butter, and a candy. Groundnut kernels are consumed directly as raw, roasted, boiled or fried. Groundnut haulms is a very good palatable (8-11% protein) fodder for cattle, when fed in green state. The groundnut cake have immense value as feeding material for livestock and organic manure. It contains 8% N, 1.4% P2O5 and 1.2% K2O.
The groundnut cake powder is used as laundry starch and in the manufacture of paper, gummed tapes and plastics. Groundnut shell is used as fuel and for manufacture of coarse boards, cork substitute and activated carbon. Groundnut shell is rich in potassium (1.5%) and calcium (3%), hence can be used as organic manure.
These multiple uses of groundnut plants makes it an excellent cash crop for domestic markets as well as for foreign trade in several developing and developed countries. Globally, 50% of the groundnut produced is used for oil extraction, 37% for confectionery use and 12% for seed purpose.
Groundnut being a leguminous crop, it has following advantages over other crops:
1. Being leguminous, groundnut has the ability to fix atmospheric nitrogen biologically into the soil which enriches the soil and this benefits the succeeding crop in rotation.
2. It is one crop which does not require much irrigation and can be cultivated on the residual soil moisture conditions.
3. It can provide gainful employment during the lean season.
4. Unlike the vegetables and fruits, which are highly perishable items, groundnuts can be stored for a long period of time and sold when prices are high.
5. It provides a very nutritive green fodder (haulms) and feed (oil cake) which can be fed to cattle and also used as organic manures.
6. Groundnut crop is considered not only as an oilseed crop but also as a food crop because its kernels are rich in protein contents and vitamins.
2. Origin and History of Groundnut:
Cultivated groundnut originates from South America. The Arachis genus was distributed in Argentina, Bolivia, Brazil, Paraguay and Uruguay with largest number of species reported from Brazil followed by Bolivia. Arachis hypogaea is believed to have originated in North Argentina and Southern Bolivia, where the diploid wild (progenitors of groundnut) species (A. batizocoi Krapov & W.C. Gregory Morten nudum and A. duranensis Krapov & W.C. Gregory nov. sp.) that are closely related to tetraploid A. hypogaea and A. monticola Krapov & Rigoni are distributed in this region.
This suggests that this region is the primary center of diversity. The secondary center of diversity includes Guarani region of Paraguay-Parana, Goias and Mina Gerais region of Tocatins, San Fransisco, Rondonia North-West Mato Grosso of Brazil, eastern foothills of the Andes and Bolivia and Peru’s upper Amazon and West Coast.
North East Brazil is considered as tertiary center of Diversity. The credit for the introduction of the groundnut into India belongs to the Jesuit Fathers who followed Vasco De Gama shortly after his first landing in India.
The flora of Western India includes a large number of specimens of South and Central American origin, introduced by missionaries. The so-called ‘indigenous’ variety in modern India was likely of Brazilian origin. Since South America was discovered in early 1500 A.D., it is probable that the plant was introduced into India at the earliest by the first half of the sixteenth century.
3. Botanical Description of Groundnut:
The groundnut is a low growing annual plant. The groundnut plant has prostrated to upright stems that sometimes reach a height of 46 cm. The plant usually grows slowly until about 40 days after planting. Plants start flowering about 25-40 days after planting. Growth is more rapid between 40-100 days. During this period 4-5 fold increase in peanut foliage occurs.
After sowing seedling emerge in 5-10 days, depending on sowing depth and soil moisture. Bunch type does 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.
Root:
The groundnut has a tap root with its laterals covering a depth of 35-40 cm and spread of 30-35 cm of radius.
Stem:
The groundnut stem is cylindrical, hairy and becomes more or less angular with age. The central stem is usually taller and has a few laterals which form main basis for classification of different varieties and forms.
Leaves:
The groundnut has a pinnately compound leaf with two pairs of leaflets. There is a pair of stipules about 4 cm long with long alternate points which are fused with the petiole for about 1 half of their length. The leaves occur alternatively 1 at each node. The shape of leaflets varies from elliptic, ovate to oblong with the entire or ciliate margins, subcardate base and obtuse or shortly mucronate tip.
Flowers:
Groundnut can flower (orange yellow in colour) over a long period depending on moisture availability, and temperature. Usually flowering takes place between 24-30 days after sowing and is little earlier in bunch than in spreading types. The flowering period normally
lasts for 3-8 weeks in case of bunch type and 6-10 weeks in case of spreading type. Three to five flowers are produced in the axils of leaves (near the base of the plant) on reproductive branches.
Groundnut is a completely self-pollinated crop i.e. its own pollen fertilizes the ovule. It is a unique plant because after pollination, the ovary elongates to produce a peg (gynophore, which contains fertilized ovules at the tip) that buries the ovary into the soil.
The peg is positively geotropic i.e., it grows towards the soil and penetrates into the soil. The peg penetrates the soil up to a depth of 7-8 cm. The ovary starts developing into a fruit (pod) after taking a horizontal position in the soil.
The pods are formed within 5-7 cm depth of surface soil and this is known as fruiting zone or pod zone. The pegs that are formed 15 cm above the soil surface usually fail to contact the soil and these will wither and hence their fertilized ovaries abort.
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. Bunch type takes 85-100 days to mature and spreading cultivars mature in 110-130 days under warm conditions.
The mature fruit may normally contain upto 4 seeds depending on variety. Single seeded pods may be produced when all ovules but the proximal abort. Seedless fruits called ‘pops’ may be produced when calcium is limiting.
Groundnut, ‘the unpredictable legume’ is also known as earthnut, peanut, monkey nut and manilla nut. It is the 13th most important food crop and 4th most important oilseed crop of the world. The botanical name Arachis hypogaea L. has been derived from the Greek words, Arachis meaning a legume and hypogaea meaning below ground referring to geocarpic nature of pod formation.
Groundnut kernels have about 25% protein which is 1.3 times higher than meat, 2.5 times higher than eggs and 8 times higher than fruit. The oil content in kernels ranges from 40-50% and is extensively used for cooking (culinary oil) and for preparing vegetable oil (vanaspati). Its oil is also used for the preparation of soaps, cosmetics, cold cream and for various industrial uses.
Its oil is now used in pharmaceutical as a substitute to oleic oil. The groundnut is dug, extracted, processed, and consumed as a snack food, peanut butter, and a candy. Groundnut kernels are consumed directly as raw, roasted, boiled or fried. Groundnut haulms is a very good palatable (8-11% protein) fodder for cattle, when fed in green state. The groundnut cake have immense value as feeding material for livestock and organic manure. It contains 8% N, 1.4% P2O5 and 1.2% K2O.
The groundnut cake powder is used as laundry starch and in the manufacture of paper, gummed tapes and plastics. Groundnut shell is used as fuel and for manufacture of coarse boards, cork substitute and activated carbon. Groundnut shell is rich in potassium (1.5%) and calcium (3%), hence can be used as organic manure.
These multiple uses of groundnut plants makes it an excellent cash crop for domestic markets as well as for foreign trade in several developing and developed countries. Globally, 50% of the groundnut produced is used for oil extraction, 37% for confectionery use and 12% for seed purpose.
Groundnut being a leguminous crop, it has following advantages over other crops:
1. Being leguminous, groundnut has the ability to fix atmospheric nitrogen biologically into the soil which enriches the soil and this benefits the succeeding crop in rotation.
2. It is one crop which does not require much irrigation and can be cultivated on the residual soil moisture conditions.
3. It can provide gainful employment during the lean season.
4. Unlike the vegetables and fruits, which are highly perishable items, groundnuts can be stored for a long period of time and sold when prices are high.
5. It provides a very nutritive green fodder (haulms) and feed (oil cake) which can be fed to cattle and also used as organic manures.
6. Groundnut crop is considered not only as an oilseed crop but also as a food crop because its kernels are rich in protein contents and vitamins.
2. Origin and History of Groundnut:
Cultivated groundnut originates from South America. The Arachis genus was distributed in Argentina, Bolivia, Brazil, Paraguay and Uruguay with largest number of species reported from Brazil followed by Bolivia. Arachis hypogaea is believed to have originated in North Argentina and Southern Bolivia, where the diploid wild (progenitors of groundnut) species (A. batizocoi Krapov & W.C. Gregory Morten nudum and A. duranensis Krapov & W.C. Gregory nov. sp.) that are closely related to tetraploid A. hypogaea and A. monticola Krapov & Rigoni are distributed in this region.
This suggests that this region is the primary center of diversity. The secondary center of diversity includes Guarani region of Paraguay-Parana, Goias and Mina Gerais region of Tocatins, San Fransisco, Rondonia North-West Mato Grosso of Brazil, eastern foothills of the Andes and Bolivia and Peru’s upper Amazon and West Coast.
North East Brazil is considered as tertiary center of Diversity. The credit for the introduction of the groundnut into India belongs to the Jesuit Fathers who followed Vasco De Gama shortly after his first landing in India.
The flora of Western India includes a large number of specimens of South and Central American origin, introduced by missionaries. The so-called ‘indigenous’ variety in modern India was likely of Brazilian origin. Since South America was discovered in early 1500 A.D., it is probable that the plant was introduced into India at the earliest by the first half of the sixteenth century.
3. Botanical Description of Groundnut:
The groundnut is a low growing annual plant. The groundnut plant has prostrated to upright stems that sometimes reach a height of 46 cm. The plant usually grows slowly until about 40 days after planting. Plants start flowering about 25-40 days after planting. Growth is more rapid between 40-100 days. During this period 4-5 fold increase in peanut foliage occurs.
After sowing seedling emerge in 5-10 days, depending on sowing depth and soil moisture. Bunch type does 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.
Root:
The groundnut has a tap root with its laterals covering a depth of 35-40 cm and spread of 30-35 cm of radius.
Stem:
The groundnut stem is cylindrical, hairy and becomes more or less angular with age. The central stem is usually taller and has a few laterals which form main basis for classification of different varieties and forms.
Leaves:
The groundnut has a pinnately compound leaf with two pairs of leaflets. There is a pair of stipules about 4 cm long with long alternate points which are fused with the petiole for about 1 half of their length. The leaves occur alternatively 1 at each node. The shape of leaflets varies from elliptic, ovate to oblong with the entire or ciliate margins, subcardate base and obtuse or shortly mucronate tip.
Flowers:
Groundnut can flower (orange yellow in colour) over a long period depending on moisture availability, and temperature. Usually flowering takes place between 24-30 days after sowing and is little earlier in bunch than in spreading types. The flowering period normally
lasts for 3-8 weeks in case of bunch type and 6-10 weeks in case of spreading type. Three to five flowers are produced in the axils of leaves (near the base of the plant) on reproductive branches.
Groundnut is a completely self-pollinated crop i.e. its own pollen fertilizes the ovule. It is a unique plant because after pollination, the ovary elongates to produce a peg (gynophore, which contains fertilized ovules at the tip) that buries the ovary into the soil.
The peg is positively geotropic i.e., it grows towards the soil and penetrates into the soil. The peg penetrates the soil up to a depth of 7-8 cm. The ovary starts developing into a fruit (pod) after taking a horizontal position in the soil.
The pods are formed within 5-7 cm depth of surface soil and this is known as fruiting zone or pod zone. The pegs that are formed 15 cm above the soil surface usually fail to contact the soil and these will wither and hence their fertilized ovaries abort.
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. Bunch type takes 85-100 days to mature and spreading cultivars mature in 110-130 days under warm conditions.
The mature fruit may normally contain upto 4 seeds depending on variety. Single seeded pods may be produced when all ovules but the proximal abort. Seedless fruits called ‘pops’ may be produced when calcium is limiting.
