Wheat rust is a serious threat to Nepal food security

Wheat is one of the major food crops across the world, including Nepal. The fall in wheat production seriously affects the world’s food chain. In recent decades, wheat farmers, especially in the African region, have suffered from many different diseases, including wheat rust.

The 2017 SAARC (South Asia Association for Regional Cooperation) Wheat Rust Surveillance & Monitoring Workshop was held in Kathmandu, 22 February-3 March, where both wheat scientists and stakeholders participated. The workshop was organized to foster regional collaboration and equip a new generation of South Asian scientists with the tools and knowledge to manage the threat of wheat rusts. The participants at the program discussed the importance of wheat as a major staple food, wheat rusts, and threat management.

Against this background, Janata Radio/Nepal interviewed Sarala Sharma, the plant pathologist focusing on the current issues of wheat rust in the context of food security of Nepal.

• What is the relevance of the SAARC workshop in the context of wheat production in Nepal?

There are several biotic and abiotic stress affecting wheat production in different parts of the world, including Nepal. Wheat rust, especially the outbreak of black (stem) rust, has posed a serious threat to the world’s food security. The black rust which re-emerged in Uganda in 1999 caused a severe wheat yield loss of more than 70 percent. To fight against this disease, the scientists, donor community, and other stakeholders have been collaborating in recent decades. This 2017 SAARC (South Asia Association for Regional Cooperation) Wheat Rust Surveillance & Monitoring Workshop is also a part of that collaboration. The participants were mainly the young scientists from India, Pakistan, Bangladesh, Afghanistan, Bhutan, Nepal, and so on. The workshop provided training on rust disease management. The participants were provided the training from highly reputable faculty trainers and scientists from Australia, USA, Ethiopia, Nepal, and South Africa, among others. Students learned about breeding for resistance, pathotypes, genotypes, and surveillance, among other topics, through lectures and field observation.

• What are the key factors that affect to wheat production in Nepal?

There are a couple of things that affect the cultivation of the wheat crop in Nepal. To increase wheat production, we need quality seeds, irrigation facilities, and availability of fertilizers. On top of that, diseases are a crucial cause of yield loss. Furthermore, wheat rust has become a serious problem as it is challenging to control once there is an outbreak.

• Could you elaborate more on the nature and problem of wheat rust?

Basically, there are three major types of wheat rust which include black (stem) rust, brown rust, and yellow (stripe) rust. Wheat crops cultivated in the Terai (flatlands of Nepal) have suffered from both brown and yellow rusts, whereas hilly areas witness the problem of yellow rust. More importantly, we are currently experiencing a big threat of black rust, which is very dangerous to the world’s wheat crop. Once Dr. Norman Borlaug invented the new genetics of resistant wheat in Mexico, it was extremely helpful in controlling black (stem) rust. Had he not invented stem rust resistant wheat (in the 1970s), we would have suffered from severe famine across the world.

• Why is wheat rust considered a serious problem?

Wheat rust is a fungal disease that spreads quickly from one place to another. Since it spreads through the air, wheat crops are highly susceptible to this disease. Wheat rust can destroy the whole production of the wheat.

• Has black rust disappeared completely or has it re-emerged in some places?

In Nepal, black rust was noticed before 1970 in local varieties of wheat plants. With the replacement of new varieties of wheat seeds, that type of black rust has not emerged. It doesn’t mean that we are free from black rust. Actually, a dangerous form of black rust re-emerged in Uganda in 1999 which is also known as Ug99. It has posed a serious threat to the world’s wheat crop due to its devastating nature. Realizing the threat of UG99, an international conference was held in Kenya in 2005 to discuss and find the solution for this problem. Since then, scientists, donors, and other stakeholders have been jointly working to fight against this disease. This encouraged the scientists across the world to work together. As a wake-up call, an international conference was initiated by CIMMYT, Cornell, FAO, and ICARDA in 2005 in Kenya where scientists — including Dr. Borlaug, the donor community, and other stakeholders — met to discuss common planning and strategies. That is how BGRI/DRRW was born. This SAARC training is a part of that initiative.

• What initiatives have been taken so far in Nepal to manage this problem?

In 2008, Nepal received eight different rust and drought resistant genotypes developed by Dr. Ravi Singh at CIMMYT. They were tested in 60 different sites before releasing for seed multiplication. After successful trials, we recommended them to farmers. Farmers liked those varieties which include Danfe, Munal, Chyakhura, Tilotma, among others, as they are rust resistant, short-stature and provide a high yield. At the same time, we developed many genotypes in Nepal and sent them to Kenya for testing to find out the rust resistance ability. Among them, only one variety — called Vijay — turned to be a rust resistant. In recognition of our work, five scientists including me from the Nepal Agricultural Research Council (NARC) received the BGRI Gene Stewardship Award in 2012.

• Is Vijay variety cultivated currently?

Yes, Vijay is cultivated in a wide area. After testing, the government of Nepal allowed distribution of the seeds of Vijay.

• How challenging is it to develop rust resistant varieties?

It requires a long process of breeding, varietal testing and continuous training. Nepal is continuously equipped in this varietal improvement program. The young scientists have provided the SAARC level training continuously for the past three years jointly by NARC, BGRI/DGGW at Cornell University, USA, and Sathguru Management Consultants, India. With the training, they are capable of developing new varieties of wheat seeds.

• Do you think Nepali farmers should worry about wheat rust?

We worked hard to rescue farmers from yellow rust. We have recommended certain rust resistant varieties to them. Our scientists are well-trained and prepared to fight against this disease. We still have the threat of yellow rust that has destroyed yields up to 90 percent in some areas. There is a tendency of farmers to cultivate the same old varieties in a big area. For instance, WK 1204 and Gautam varieties cover a wide area. We don’t recommend that farmers use the same varieties for a long time over such a wide area.

• Why is this so?

Planting old varieties over a wide area of cultivation is risky because it encourages the evolution of virulent races of pathogens. Different varieties of wheat with genetic diversification are needed to avoid that risk.

• How do farmers identify wheat rust? Are Nepali farmers aware of rust management?

The color of yellow rust looks like turmeric power and is a kind of fungus. Sometimes it develops in the seedling phase. Black rust looks like a kind of red brick color, which appears in stem. From 2008 to 2011, we worked in 10 yellow rust-affected districts with Participatory Varietal Selection (PVS) approaches where we provided extensive training to the communities. There is an improvement in farmers’ awareness level. A series of follow-up programs were also conducted until 2015.

• Is there any other serious disease in the wheat crops in Nepal?

The common wheat diseases that have appeared in our wheat crops are mostly related to fungus. They are not virus- or bacteria-related diseases. Leaf Blight and Karnal Bunt are some other common problem we face in wheat. • Can wheat diseases be controlled through the use of pesticides? We can but pesticides are not the best way to control wheat diseases. First, pesticides are expensive to buy. Furthermore, it not considered a good solution from the perspective of human health or the environment.

This translation by freelance journalist Maina Dhital is based on an interview of Dr. Sarala Sharma broadcast on February 26, 2017 by Nepal-based Janata radio and its online version Janatanews.com.