Bangladesh has developed 87 modern rice varieties in the last five decades, but only a handful of them have become popular among farmers who are not adequately informed about the features of all of the varieties.
Because of the gap between research and extension, it takes 15-16 years from the release of a variety to reach its peak of adoption, said Humnath Bhandari, the representative of the International Rice Research Institute (IRRI) for Bangladesh.
“As a result, only four to five varieties have become popular,” he told The Daily Star in an interview recently.
He said there is a problem with the extension and a good extension system should be designed so that new varieties quickly reach farmers.
The IRRI found in a recent Rice Monitoring Survey that BRRI Dhan-28, BRRI Dhan-29 and Jira Dhan are the most popular varieties in the Boro season, which stretches from November to April.
On the other hand, Swarna, Motadhan, BR-11 and BRRI Dhan-49 are the widely cultivated rice varieties during the Aman season; the crops are harvested in October-November.
Two high-yielding varieties -- BRRI Dhan-28 and BRRI Dhan-29 -- were grown on 36 percent and 33 percent area respectively during the Boro season in 2016, according to the survey.
Cultivation of Jira Dhan, BRRI Dhan-50 and Miniket has been expanding since 2013.
In the Aman season, cultivation area of Swarna rice remained steady at 24 percent between 2013 and 2016.
Farmers also increased the acreage of BR-22 and BRRI Dhan-49 during the period and reduced the farming of BR-11 marginally between 2013 and 2016.
The survey, which was carried out among 1,500 farmers, aimed at seeing the adoption of developed varieties and areas under their coverage as well as helping policymakers frame better policies.
Bhandari said the Bangladesh Agricultural Development Corporation, the state-run seed producer, produces a seed only when there is a huge demand for the variety.
Farmers will only try out a new variety when they know about it and reap benefits, he said.
“Unless we educate farmers, there will not be an increase in demand,” he said.
He called for a strong research and extension linkage so that new varieties reach farmers through the Department of Agricultural Extension.
Bhandari said more interaction between the research centres and the extension department is required.
The agricultural economist said bringing in new varieties fast to farmers' doorstep is important to ensure higher yields because their genetic potential declines as they grow older.
Varieties start degenerating within five years to six years after their release, he said.
He said BRRI Dhan-28 and BRRI Dhan-29 are more than 20 years old; the yield potential of the two popular varieties is declining and they have become more susceptible to disease.
“Besides, climate is changing. So, it is important to replace the old varieties with the new ones to increase productivity.”
According to Bhandari, seed needs to be replaced in every three years as yield potential declines for their continuous use.
Currently, only 20 percent to 30 percent farmers replace seeds, he said.
Bhandari said replacement of old varieties by new ones and regular replacement of seed will increase rice yield by 20-30 percent.
The potential for yield increase is 30-40 percent in the Aman rice cultivation season and about 20 percent in the Boro season. This is particularly important given the falling growth rate of rice yield over the years.
“With the changing context of increasing population and declining land, the only option is to boost rice yield,” Bhandari.
“If we can educate farmers about the need to replace old seeds with new ones in every three years, productivity will go up. This will also boost the national food security.”
He suggested providing technology, training and information to farmers quickly.
“New varieties are more knowledge-intensive. So, along with technology, we need to provide management practices.”
The IRRI official said farmers adopt new technology when they see the benefit.
He suggested using ICT to circulate information, setting up demonstration sites in every district for new varieties, and growing 10-15 varieties in a certain area of a district.c