Wheat blast in Bangladesh: CSISA–BARI collaborative research

CSISA is collaborating with the Wheat Research Centre (WRC) of the Bangladesh Agriculture Research Institute (BARI) to develop a model for identifying wheat blast resistant varieties and approaches to mitigate the disease. In 2017, a blast resistant, zinc-enriched variety, BARI Gom 33, was released. This variety was validated in last year’s blast-affected farmers’ fields, and field days were organized to demonstrate its resistance to farmers, government organizations, NGOs and private sector companies. Most field day participants indicated that they liked BARI Gom 33, and farmers were advised to preserve its seed.

This important research came about through multi-party collaboration. Activities were supported by CSISA through the United States Agency for International Development (USAID) and the Bill & Melinda Gates Foundation. Research was facilitated by the USAID Mission in Bangladesh with the support of the Australian Centre for International Agricultural Research by leveraging the capacity of the International Maize and Wheat Improvement Center (CIMMYT) through a project titled “Identification of sources of resistance to wheat blast and their deployment in wheat varieties adapted to Bangladesh.”

The first-ever outbreak of wheat blast outside South America, where it was first reported, was recorded in Bangladesh in February 2016. This is a fearsome fungal disease caused by Magnaporthe oryzae pathotype Triticum (MoT), that now affects over 15,000 hectares in seven southwestern and southern districts of Bangladesh. The estimated average yield loss is 25–30%, but in severely infected fields, total losses have also been observed.

The Ministry of Agriculture of Bangladesh officially announced the presence of wheat blast on 27 March 2016, and formed a technical sub-committee including CIMMYT to create an action plan to mitigate the disease.

An international consultative meeting was held in 2016 in Kathmandu, Nepal, and in 2017 in Dhaka, Bangladesh, to plan short-, medium- and long-term strategies to mitigate the disease. International training courses for wheat scientists from India, Nepal and Bangladesh were organized at the Wheat Research Centre (WRC), Dinajpur, and the Regional Agricultural Research Station (RARS), Jashore, in 2017 and 2018, respectively. Field surveillance was conducted through CSISA in partnership with USAID and the Bill & Melinda Gates Foundation.

Recommendations were presented to farmers in a factsheet through government, NGO and private sector partners in 2017 and 2018. Recommendations included early seeding to help crops avoid high temperatures and early rains at heading, collection of seeds from blast-free areas, seed treatment, cultivation of resistant varieties, preventive foliar spray at heading and 12–15 days after heading, weed-free cultivation and rotation with non-wheat crops.

Wheat blast-affected areas in 2017 and 2018 shrank to only 22 and 16 ha with low, sporadic infection due to farmers adopting the recommendations and climate conditions that were less favorable for blast spread. However, trace infection was found in three new areas in 2017 and two new areas in 2018, outside districts infected in previous years. This indicates the ongoing spread of the disease and its adaptability to new environments, underscoring the potential for its spread. Symptoms of wheat blast infection were also found on Digitaria, Eleusine indica, and Panicum repens, common weed species found throughout Bangladesh, but research is underway to confirm whether spores from these species can infect wheat and vice versa.

WRC and BARI, in collaboration with CIMMYT, will undertake a seed production program in farmers’ fields in the coming season and will distribute the seed to farmers.

Wheat blast surveillance work was conducted in 2017 and 2018, and laboratory confirmation is underway at WRC/BARI laboratories, with the support of CSISA. Blast mitigation trials have continued in 2018 at a hot spot in RARS, Jashore. Out of 25 advanced lines, 7 were found to be resistant (<10% disease index). Out of 408 germplasm lines, seven (including Borlaug 100) had zero disease index and 164 were resistant (<10% disease index). A seeding experiment showed that there was no disease in six new varieties, including susceptible BARI Gom 26, which were sown on 25 November and 5 December. However, on BARI Gom 26 planted on 4 January, seeding disease severity was >85%. The effectiveness of seed treatments and foliar spray fungicides was confirmed by the 2018 results.

Author: Dr. Dinabandhu Pandit, Sarah Sayeed Gazi and M. Shahidul Haque Khan