Boro production has remained almost static for the past three consecutive seasons, raising concern over the future food security of Bangladesh.
Experts opined that monopoly cultivation of some selected varieties has been making rice production vulnerable during Boro season as temperature dwindles.
They emphasised developing multiple stress-tolerant and stress-resistant rice varieties and raising the use of modern farm machinery for substantial Boro output.
Boro contributes 56 per cent to the domestic demand for rice.
Boro harvest has begun in full swing with a target to achieve an all-time high of 20.5-million tonnes to maintain smooth supply of the staple during this second coronavirus wave.
But experts doubt about achieving the production target this year too following substantial damage caused by heat stress and rice blast in many areas.
In fiscal year (FY) 2016-17, Boro production fell to a decade low of 18.1-million tonnes amid a flash flood in haor as well as crop damage in some regions, according to the Bangladesh Bureau of Statistics.
For a drop of above 1.0-million tonnes, rice prices hit an all-time high in September 2017 as coarse rice retailed at over Tk 55 a kg, disclosed the Trading Corporation of Bangladesh.
During the FY'18 Boro season, according to the bureau, production reached a record 19.57-million tonnes. But it fell slightly to 19.56-million tonnes in FY'19 and then increased to 19.63-million tonnes in FY'20.
"The trend of the last three years is indicating that the growth of production has almost remained stuck in Boro season amid various reasons," seed technologist Md Shahjahan Ali said.
"Monopoly cultivation of some selected rice species in Boro season, high temperature from mid-March to April, lack of multiple stress-resistant rice varieties and seasonal disasters in April are to blame."
Mr Ali said 50 per cent of land in Boro season is occupied with only two high-yielding varieties -- BRRI dhan-28 and 29 (24 per cent and 26 per cent respectively) -- developed by the Bangladesh Rice Research Institute (BRRI) in 1992.
Producing same varieties on a same piece of land for three decades has made the species vulnerable both to diseases and imbalance of temperature, he stated.
For the past three decades, any other varieties, developed by government agencies could hardly manage to get space in more than 10 per cent of the Boro land.
Only BRRI dhan-58 has been able to capture 8.0 per cent of land in the last eight years but it is a parallel variety of BRRI dhan-29 that takes a week lesser to mature, he said.
According to Mr Ali, hit stress and fungal disease like blast attack all of the three varieties every year.
He said there is a lack of 'abiotic stress-tolerant' varieties in Boro season which could tolerate submergence, drought, salinity or imbalance of temperature and other natural calamities.
"We also lack 'biotic stress-resistant' species which can fight multiple diseases, pests or fungi."
Mr Ali suggested that the agency concerned put emphasis on participatory variety selection (PVS) so that developed species could be farmer-friendly.
Farmers are now using above 200 hybrid varieties of which state agencies and universities are providing only 15 varieties while the rest by the private sector.
Hybrid seeds should also be regulated frequently by government agencies to check any crop damage, he cited.
Delwar Jahan, founder of Prakritik Krishi, an organisation that works for chemical-free agriculture, said state agencies are hovering around some selected 'genetic lines' to develop Boro rice varieties.
Despite controversies, he said, the BRRI has been working to release a vitamin-A enriched genetically modified variety, golden rice, which is just an engineered version of BRRI dhan-29.
The newly released BRRI dhan-89 and 92 are also similar to BRRI dhan-29, he said.
Ecologist Pavel Partho said the government agency concerned must introduce Boro indigenous rice varieties which were largely grown in haor and other lowlands following the changing behaviour of climate.
He said Samudra Fena, Jagli Boro, Boiya Khauri, Lakhai, Kali Boro, Dholi Boro, Sada Rata, Kala Rata, Sokalmukhi, Hatibabndha, Churag and several other Boro varieties were still available in haor area which should be appropriated in other regions through PVS.
The biodiversity specialist said most of these varieties are stress-tolerant and stress-resistant.
Hatibandha and Churag varieties can even tolerate hailstorm and lightning during nor'wester while Jagli or Lakhai is submergence-tolerant.
"So, the agencies concerned should take help from the local haor farm community to develop multi stress-tolerant and resistant varieties for the sake of the country's future food security."
BRRI director general Dr Md Shahjahan Kabir said they have already developed many varieties alternative to BRRI dhan-28.
They include BRRI dhan-67, 74, 81, 84, 86, 88, 96 and 100, he added. The 29 varieties have also alternatives like 58, 80, 92.
Those varieties are physical stress-tolerant, disease-resistant as well as short-duration and their production is much better, Mr Kabir said.
The BRRI is developing rice varieties while emphasising participatory plant breeding and PVS.
It has recently developed a rice variety for haor which is short-duration and submergence-tolerant and it would be released soon.
Mr Kabir said the variety has been developed from an indigenous haor variety.
He said the Bangladesh Agricultural Development Corporation and the Department of Agricultural Extension would have to boost the BRRI-released new varieties at farmers' level.
Prof Golam Hafeez Kennedy, value-chain expert and agri-economist, said a fall in Boro rice production or remaining the same might affect future rice security as it contributes more than 56 per cent of the total rice output.
He said land under Boro farming was between 4.7 million and 4.89-million hectares in the past 10 years.
"There is no other option but raise productivity dramatically which is hovering between 3.97 to 4.0 tonnes per hectare for a decade," he said.
Apart from the local HYV varieties, Dr Kennedy said, performance of imported hybrid ones should be reviewed regularly and only suitable ones should be permitted.
Marketing channels should be modernised so the government could buy paddy directly from farmers, store those at community storages run by farmers, he opined.
Farmers should be given logical incentives both in input and cash forms to keep them in farming which is a great challenge of this millennium, the expert noted.
The peasantry should be equipped with modern farm machinery through incentivising them to ensure maximum production, he said.
He said nearly 0.1-million hectares of Boro land has been affected by heat stress and blast this year.
The government should deliver authentic data on production loss of specific varieties in specific regions so that organisations involved in seed development could follow the data while developing new varieties, Mr Kennedy added.