Evolution of Trombay Groundnut (TG)

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Sustained research using mutation and recombination breeding at BARC resulted in the release of 12 TG varieties for commercial cultivation in the country. TG 1 was the first induced large seed mutant variety developed by X-ray irradiation of ‘Spanish Improved’ variety and released in India. Another direct mutant, ‘TG 3’ was released for Kerala state and became popular in Orissa state. Subsequently, TG 37A, TG 38, TPG 41 and TLG 45 were recently released.



The cultivated groundnut (Arachis hypogaea L.) in India is an important oilseed, food and feed crop grown in an area of 6.45 million hectares with a total production of 6.57 million tons. This contributes to 26.6% of world’s groundnut area and 18.5% of world’s groundnut production.

Trombay groundnut varieties are very popular among the farming community and are cultivated throughout the nation in view of their higher yields, early maturity and better water use efficiency. Some of them have an additional useful trait of fresh seed dormancy of 20-30 days thus preventing in situ seed germination due to end season rains when the crop is ready for harvest. This trait is very useful under current changing climatic conditions wherein unpredictable rains are often experienced.



TG development procedure

In most of the groundnut mutation experiments, the objectives were to develop high yielding varieties with early maturity, high harvest index, large seed, high oil content, high shelling percentage, moderate seed dormancy, tolerance to biotic and abiotic stresses and improved seed quality traits. The radiation source used for groundnut breeding in the early years was X-rays. Later, gamma rays took a leading role in mutation breeding. The effective dose of 200-350 Gy gamma rays was close to lethal dose (LD) 50 depending on the factors influencing radio-sensitivity at the time of mutagen treatment.



Yield potential of different TG varieties

Among the released TG varieties, TAG-24, TG-26, TG 37A, TG 38, TG 51 in normal seed class and TKG 19A, Somnath, TPG 41, TLG 45 in large seed class are popular among the farmers of major groundnut growing states such as Gujarat, Andhra Pradesh, Maharashtra, Karnataka, Orissa and Rajasthan and are also becoming popular in West Bengal, Punjab and Tamil Nadu, Madhya Pradesh, Uttar Pradesh and Goa. TAG-24 is the most popular TG variety grown throughout the country & farmers have been realizing the high yielding ability of groundnut varieties by harvesting record groundnut yields in many parts of the country. Hundreds of farmers were harvesting significant improved productivity even up to 7 tonnes/ha when recently released groundnut varieties were introduced in these states.

One of the notable contribution of BARC has been in the development of early maturing confectionery grade large seed groundnut varieties (100-seed weight >60g) suitable for export and Table purpose. Existing large seed varieties were with long duration, longer seed dormancy and low productivity. However the recently released large seed mutant varieties like TBG (TDG) 39, TPG 41 and TLG 45 benefited many farmers by virtue of their earliness, moderate seed dormancy and superior productivity.  

Other economic benefits of TG varieties in agriculture & research

Trombay varieties also facilitated farmers to develop newer cropping systems like intercropping groundnut with sweet corn, sugarcane; onion and use of polythene mulch technology for intensive groundnut cultivation. Mutation breeding programme is also complemented with biotechnological approaches. Molecular markers are useful in crop improvement programmes for varietal identification, marker assisted selection, estimating genetic distances, linkage studies, phylogenetic analysis and tagging and cloning of desirable genes.     

Specification and features of TG varieties released

S. NoVarietyYear of releasePedigreeReleased forSpecial feature
1TG 11973

X-ray mutant of   


High yield, large seed

2TG 31985

X-ray mutant of   


High yield

3TG 171985

Dark green leaf   
mutant X TG 1


Less number of   


TG 18A X M 13


Large seed,   
Semi-runner type and most suitable for snacks and butter manufacturing

5TKG 19 A1993

TG 17´TG 1


Large seed size,   
Fresh seed dormancy

6TG 221992

Robut 33-1 X   
TG 17


Medium seed size,   
Fresh seed dormancy

7TAG 241992


Maharashtra, Orissa,   
West Bengal

Semi-dwarf, earliness,   
High yield, high   
partitioning %

8TG 261996


Gujarat, North   
Madhya Pradesh

High partitioning%,   
Fresh seed dormancy,   
smooth pods

9TG 37A2004

TG 25 X TG 26

Haryana, Rajasthan,   
Punjab, Uttar   
Pradesh, Gujarat,   
Orissa, West   
Bengal, Assam,   
North Eastern states

High yield, wider   
adaptability, collar rot   

10TG 382006

Gamma ray   
mutant from the   
cross Girnar-1 X   
TG 26

Orissa, West   
Bengal, Assam,   
North Eastern states

High shelling %, stem   
rot tolerance, more   
3-seeded pods,

11TPG 412004

TG 28A X TG   

All India

Large seed, Medium   
maturity, High oleic   

12TLG 452007

TG 19 X TAG   


Large seed, Medium   



In TG breeding, a relatively major portion (67.7%) of the TG base was shared by ‘Spanish Improved variety’ and rest by very few cultivars, which made the TG base so narrow. However, induced mutants themselves or their use in recombination breeding with other mutants and/or cultivars has led to the evolution of several distinct TG lines with improved agronomic traits (Kale et al. 2000). This was made possible by the successful isolation of mutants and by bringing mutant genes into ideal genetic backgrounds. Thus, the judicious use of mutation and recombination breeding has great potential for genetic enhancement in groundnut.


Key Words

Trombay Groundnuts (TG), TAG, Somnath, Mutation breeding, BARC


A. M. Badigannavar, D. M. Kale, G. S. S. Murty, Genetic base and diversity in groundnut genotypes, Jan 24 2002   
Suvendu Mondal, Mutation experiments and recent accomplishments in Trombay groundnuts, Jan 2007


Key Takeaways

• TAG-24 is the most popular TG variety grown throughout the country for high yield   
• Somnath variety was identified the best among TG groundnuts in sensory attributes   
• Trombay varieties also facilitated farmers to develop newer cropping systems

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