Food security: Climate change is affecting the seeds that India depends on

An increase in number of days with extreme temperatures or rain has caused a decline in quality and size of seeds across India

By Shagun, Vivek Mishra
Published: Wednesday 05 April 2023
Most wheat varieties require a day temperature of under 25°C in February-March, but 2022 saw a severe heatwave, when temperature crossed 30°C on several days in March (Photograph: Vikas Choudhary)

When a group of 20 farmers in Andhra Pradesh’s Alluri Sitharama Raju district ventured into production of seeds of finger millet (ragi) and little millet (samai) in 2019, it had no idea what the future had in store.

For the next two years, unusual weather events ensured that the crops did not have grains good enough for use as seeds.

“The years 2020 and 2021 saw excess rain in July and August. This did not allow the plants to take nutrition from the soil. The resultant grains were weak and the endosperm—part of a seed that stores food for the development of a plant and is crucial for germination—was absent when the seeds were crushed open for inspection,” says M L Sanyasi Rao, programme manager of Watershed Support Services and Activities Network, a non-profit working with tribal farmers in the area.

The farmers had estimated 20 tonnes of produce, but the harvest in November 2021 resulted in only 15 tonnes, with the grains unusable as seeds. The harvest was then sold as crop for Rs 25 per kg, while its sale as seed would have fetched R35 per kg.

There is no difference in the cultivation mechanism for producing seeds or for growing crops. Vast majority of farmers in India set aside a part of their field for growing seeds that can be used the next season.

But climate change has posed a threat to seeds, which are essential for food security of the country. Grains of wheat and rice, the two staples distributed under the government’s public distribution system and crucial to food security, have also seen a shrinkage in recent years, say farmers.

“Usually, the share of light or weak grains is 5-7 per cent. But last year, over 20 per cent of my wheat grains were of poor quality. These cannot be used as seeds,” says Vikas Choudhary, a farmer from Karnal district in Haryana.

Choudhary works as a participatory farmer with the Indian Agricultural Research Institute (IARI) under Indian Council of Agricultural Research’s (ICAR’s) seed production programme.

Wheat, paddy hit

Most wheat varieties require a temperature of under 25°C during the day in February-March, when the plant is at the grain filling stage. A 1°C temperature rise above 25°C shortens the reproductive phase by 6 per cent and the grain-filling duration by 5 per cent, reducing the yield, says Climate Change and Global Crop Productivity, a book published in 2000.

Data with India Meteorological Department shows that the 25°C limit often gets breached. March 2022 had several days with temperature crossing 30°C, reducing wheat yields in the north and central Indian states.

The country produced 106.84 million tonnes of wheat in the 2021-22 crop season, which is less than 109.59 million tonnes produced in 2021, as per data with the Union Ministry of Agriculture and Farmers’ Welfare.

Similar was the case with paddy. In August 2022, Punjab, Haryana and Uttarakhand witnessed spread of dwarf virus in paddy.

Experts say that high temperature in May and June was among the likely reasons for the spread of the disease, which causes stunting of the plant.

Drought during the early development of the seeds also reduces their quality at maturity. Paddy is also adversely affected due to excess rains.

Harbhagwan Ghai, a Karnal-based farmer involved in seed production for past 15 years, says that in the last few years, the paddy plant is getting impacted at the flowering stage in September-October due to continuous and heavy rainfall.

“The shine of the grain gets reduced if excess rainfall happens at the flowering stage. It also affects pollination. No pollen means no seeds,” he says.

Apart from an increase in temperature and rain events, another worry for farmers has been high speed winds.

“These usually blow across north India in March, but this year February saw high winds. This is the time when the wheat crop is flowering and pollination is happening. If farmers have just watered the fields and winds occur, the plant gets unsettled by the root,” says Virender Kumar from Seedhepur village in Karnal.

Heat, rain impact

Rise in temperature damages crops in multiple ways. It hastens crop development, shortening the seed filling duration. It speeds reproductive development and pollen formation, leading to development of smaller seeds.

Heat stress can also trigger early or delayed flowering. A high temperature stress before seeds reach physiological maturity can reduce germination by inhibiting the ability of the plant to supply the assimilates necessary to synthesise the storage compounds required for the germination process, and/or the seeds suffer physiological damage to the extent that the ability to germinate is lost.

A 2016 paper in Agriculture also mentions how elevated carbon dioxide (CO2) and temperature alter the sexual reproductive phase in plants, and hamper genetic quality in seeds.

“Elevated CO2 and temperature can induce changes in the sexuality in crops plants, including a breakdown in self-incompatibility or male sterility mechanisms. Breakdown of these genetic mechanisms results in self-pollination. As a consequence, the genetic integrity of the cultivar is lost and any seed produced will no longer be true-to-type,” it says.

Research has found global evidence on the link between high temperature and yield across crops, such as maize and soybeans.

Resistant varieties

Agricultural scientists consider improved seeds and varieties adapted to regions with different agricultural climates an effective solution to the problem. This is the reason disease- and climate- resilient varieties have been developed in the last few decades.

Gaurav Tripathi, senior research analyst at non-profit International Food Policy Research Institute, New Delhi, says ICAR has been releasing varieties that can fight heat, disease and extreme weather since 2005.

For example, central and state governments have notified 448 wheat varieties for cultivation between 1965 and 2018, as per “Wheat varieties notified in India since 1965” published by ICAR’s Indian Institute of Wheat and Barley Research in 2018.

Of these, about 150 varieties have been released after 2005. “But efforts to popularise new varieties have not borne result because the agriculture department has not been able to convince farmers to grow them,” says Tripathi.

ICAR’s “Vision 2025” document released in 2007 says that the “percentage of share of IARI varieties in total breeder seed production in the country varies from 20.4% to 32.9% in wheat”.

Rest of the seeds used are either developed by farmers themselves or by private companies. Ramesh Singh, head of wheat programme at Banaras Hindu University, Uttar Pradesh, says that seed replacement ratio (share of new seeds used every year) of wheat in India is only up to 20 per cent, which shows that farmers continue to grow old varieties.

In February 2023, IARI registered a new heatwave-resistant wheat variety, HD3385, which is being tested at multiple locations in the current rabi season.

The variety is sown early and harvested by March-end, before extreme heat sets in. In public-private-partnership mode, the variety is being sold by Biosey, a DCM Shriram Ltd company, with the government getting a royalty on every kilogramme of seed sold.

This is the first time a seed developed by government is being sold by a private company. “The initiative is aimed at ensuring the variety reaches a large number of farmers,” says an agriculture department official requesting anonymity.

“No matter how many varieties we create, none can withstand 40°C,” Rajbir Yadav, principal scientist and weed breeder, ICAR, New Delhi, tells Down To Earth.

“Though I grow my own seeds, and develop new wheat and paddy varieties, I had to go to Uttarakhand last year to buy 100 tonnes of seeds from a private company, after I lost 40 per cent of my produce due to heat,” says Chandrashekhar, Singh a farmer and Padmashree awardee based in Varanasi, Uttar Pradesh.

The UN Intergovernmental Panel on Climate Change’s Synthesis Report, released on March 20, says that the rate of rise in agricultural productivity has declined over the past 50 years due to climate change, with “related negative impacts mainly in mid- and low-latitude regions”.

Since this region includes vast parts of India, the country must ensure that its agricultural productivity, which depends on seeds, remains intact.

This was first published in the 1-15 April, 2023 print edition of Down To Earth

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