Hybrid Tetraploid True Potato Seed (TPS) production in Tripura, India

Dr. Sampriti Baruah, Regional Research Specialist, International Potato Center
Dr. Rajib Ghosh, Deputy Director, Department of Agriculture and Farmer’s Welfare, Government of Tripura.

Background

Potatoes play a significant role in Tripura’s agriculture, particularly during the winter season. Around half of the total cultivation cost is allocated to procuring seed tubers. However, obtaining high-quality, disease-free seed tubers poses a challenge as they need to be sourced from distant states like Punjab and Haryana, which are approximately 2800 kilometres away. The opportunity to grow disease free potatoes from TPS was considered a viable alternative and developed successfully in Tripura.

Public and Private Partners

Department of Horticulture & Soil Conservation, Government of Tripura: initiated this work with CIP in the early 1990s. By the mid 1990s, about 1500 ha were cultivated with these hybrid TPS and the tuber off spring being multiplied several times. The department has boldly continued this work to meet the needs of the Tripura farmers as well as supplying TPS to requests from other states.

International Potato Center (CIP): Under the leadership of Mahesh Upadhya, excellent tetraploid parental lines were developed for both the female and male parents. By 1993, the ideal parents had been selected and had proven in field trials across 4 states that the progenies gave excellent yields of uniform tubers for shape and skin color. The parents, having some late blight resistance, were also fertile as either a female or male parent (CIP Annual Reports 1991, 1994 and 1995-6). The female parents chosen were: MF-1, MF-2 and TPS-7. The 2 best male parents were: TPS-13 and TPS-67. These were shared with Central Potato Research Institute in 1993.

Potato farmers of Tripura immediately saw the benefits of clean planting material with TPS. They have driven the demand that continues in an extraordinary way.

State partners throughout India request TPS from the Tripura authorities and utilize the seed in various ways in their own states with farmers or government agencies.

The strategy

True Potato Seed (TPS) production in a large crossing block was established at the Horticulture Research Complex in Nagicherra, under the Department of Horticulture & Soil Conservation, Government of Tripura.

TPS production consisting of two parts:

1. Multiplication unit includes pre-basic (Generation 1) potato tubers are produced inside the aphid proof net houses using tissue culture plantlets of different male and female parental lines (picture 1). Further multiplication of basic (Generation 2) tubers are produced in open field using the pre-basic tubers of the 5 parental lines.
2. Crossing block is established in the field. Here TPS are produced using basic potato tubers of different male and female parental lines. Two male parental line namely TPS-67, TPS-13 and three female parental lines namely MF-I, MF-II, TPS-7 are grown separately, and hand pollination is done after flowering for fruit formation (Pictures 2 and 3). Artificial illumination is given to extend photoperiod by 5-6 hours to encourage abundant flowering. Male flowers are plucked, pollen grains are collected, and hand pollination is done to female flowers between MF I x TPS-13, MF II x TPS 67, TPS 7 x TPS 67. After pollination, berries on the female plants are plucked after maturity and hybrid true potato seeds are extracted with varietal names HPS II/67, HPS 7/67, HPS I/13. The whole activity is done within the period from October to April, every year.

This complete cycle i.e. from tissue culture plantlet production to pre-basic seed tuber to basic seed tuber to fruiting, seed production takes almost 3 years. The crossing block covers up to 1.0 Ha area.

Hybrid TPS thus produced are distributed among selected registered potato growers through departmental initiatives for production of certified TPS tuberlets for distribution among the potato cultivators in the next season for production of table potatoes. Some TPS are directly purchased by farmers for production of TPS tuberlet or for production of table potato in the same year by planting potato seedlings (Table 1).

 

Table 1. Hybrid TPS production at HRC, Nagicherra during the past 3 seasons

Sl. No.	Year	Name of Variety	Area (in Ha)	Qnty. of Seed produced (in Kg)
1	2021-22	HPS II/67	0.895	97.7
		HPS 7/67	0.09	8.8
		HPS I/13	0.015	1.4
2	2022-23	HPS II/67	0.935	64.4
		HPS 7/67	0.05	4.7
		HPS I/13	0.015	1.4
3	2023-24	HPS II/67	0.4	35.4
		HPS 7/67	0.05	1.1
		HPS I/13	0.01	1.8

Certain batches of TPS are dispatched to various government and private institutions, organizations, and companies upon request, both domestically and internationally, subject to prior approval from the department (Table 2). Presently, TPS seeds are exclusively produced within the state of Tripura, making it a unique endeavour in India.

 

Table 2. Hybrid TPS dispatched outside of Tripura State

Sl. No.	Year	Consignee and State of India	Qnty. of seed dispatched (in Kg)
1	2021-22	Mitul Kr, Saikia, Sr., AICRP on Potato Assam Agriculture University, Jorhat, Assam	0.25
2		Luhit Chetia, Lakhimpur, Assam	0.02
3		Bibekananda sanyal, Santoshpur, West Bengal	0.2
4		Qadir Sen laskar, Silchar, Assam	0.02
5		Dy. General manager, Bongaigoan Refinery, Assam	0.1
6		R.V Maurya, Avas Vikas Basti, City, Uttar Pradesh	0.207
7		Tapas Saha, Cooch Bihar, West Bengal	0.04
		Total	0.837
1	2022-23	R.V Maurya, Avas Vikas Basti, City, Uttar Pradesh	0.2
2		Mitul Kr, Saikia, Sr., AICRP on Potato Assam Agriculture University, Jorhat Assam	0.2
3		Tapas saha, Cooch Bihar, West Bengal	0.1
4		Luhit Chetia, Lakhimpur, Assam	0.03
5		Nikshep Ramesh Daoxan Pvt. Ltd., Karnataka	1.5
		Total	2.03
1	2023-24	Green Glove Seeds, 16, APMC Market Jalna, 2023	0.3
2		R.D. Yadav, Jila Udyan Adhikary, U.P.	0.15
3		M. P. Rao, YSR Horti. University, A.P.	0.15
4		NandKisor Parab, Pune	0.1
5		Bipul Roy, Purba Kathal Bari, Alipurduar, W.B.	0.01
		Total	0.71

In the state of Tripura, there is a significant demand for TPS due to its ready availability, disease-free nature, ease of transport, and high productivity resulting from its hybrid vigor. Only 100 gm is sufficient to cover one hectare. The cost of TPS stands at Rs. 30,000 (US$360)/kg. According to information shared by the department of Agriculture and Farmers’ Welfare, the cost of production of potato using TPS, is approximately 55% less compared to using seed tuber.

Lessons learned

The careful selection of excellent female and male parents allows for abundant fruit set of hybrid tetraploid TPS. The cost to produce a kilogram is only US$360, which could potentially be sufficient for 10 hectares! The uniformity of the hybrid TPS is so good that after nearly 3 decades the potatoes from the 3 preferred crosses remain popular and are not replaced by vegetatively produced varieties. The high level of late blight resistance is a key attribute for the popularity of these 3 hybrids. HPS II/67 is the most popular hybrid primarily due to its highly attractive tuber appearance and superior tuber yield.
The unique success in Tripura is a testament to the long term dedicated leadership by all the key agencies involved. This contrasts to many other TPS programs initiated in the 1990s that did not continue beyond the projects’ donor funding.