A project of the General Economics Division of the Bangladesh Planning Commission funded by the Government of the Netherlands

  • Possibility of salinity and salt-tolerant rice in coastal-belts

    At present, rice productivity in salt affected areas is very low as around one ton per hectare. But this potentially increases by at least two to three tons per hectare with improved newly developed rice varieties that can withstand soil salinity. A significant number of farmers still cultivating boro rice in salt affected areas while most of them are using BRRI dhan28 (a non-salt tolerant rice variety) as one of the most popular varieties in Bangladesh.

    Earlier, farmers received good yield from this variety, but now-a-days, they are facing serious problems to get a good harvest from these non-salt tolerant rice varieties in boro season due to increased salinity intrusion in these areas while the trend of salinity intrusion in coastal-belt is still increasing. Scientists have comprehensive rice research and breeding programme to make climate-ready rice varieties that are more tolerant of submergence, drought, heat and salinity conditions predicted to increase in frequency and severity with climate change. However, every type of stressed environment requires that a rice plant has a unique trait combination to be adaptable. This is complicated by changes associated with climate that include increased temperature and sea-level rise.

    IRRI scientists have identified rice genome called “Saltol” – a gene that confers salinity tolerance. This “Saltol” gene had been incorporated into this variety, and this had shown significant tolerance of salinity. Through molecular assisted breeding, the IRRI multi-disciplinary team on salinity tolerance composed of physiologists and molecular biologists were able to introgression “Saltol” into popular rice varieties that gives the rice plant tolerance to salinity. “Saltol” is being used to help develop varieties that can cope with exposure to salt during the seedling and reproductive stage of the plant.  The development and introduction of new varieties and corresponding dissemination measures are important and need to be facilitated by the international or national research. One of these varieties is BRRI dhan47, which was released in Bangladesh in 2007. It’s an IRRI-bred variety, labeled as IR63307-4B-4-3, and introduced to BRRI under IRRI-BRRI collaboration. The variety evaluated by the technical committee and then released by the National Seed Board of Ministry of Agriculture, as salt-tolerant rice variety, recommended to cultivate in boro season. The development of BRRI dhan47 is one of the best results of a strong and effective collaboration between IRRI and BRRI. Right now, a number of salt tolerant rice varieties have been developed by the IRRI-BRRI-BINA collaboration and they are now available in the country to demonstrate at coastal belt that rice plants can defy salt. By this time, the country has introduced four saline tolerant rice varieties for boro season which have been released by the National Seed Board of Ministry of Agriculture to scale-up production by fighting the effects of climate change. These four released varieties are making the farmers more prepared to face the impact of climate change. All these four varieties having capacity to fight salinity condition have started reaching the farmers through government and international agency like IRRI. BRRI is working for developing another two salt tolerant rice varieties targeting the boro season in southern Bangladesh. These two saline tolerant varieties which are expected to be released soon have yield potential up to 6.5 ton per hectare at normal condition while yield will be around 4 ton per hectare under saline condition. These two varieties definitely will also be an important addition for coastal farmers to grow rice during the boro season in the southern Bangladesh.

    In 2012 and 2013, STRASA-USAID-IRRI project distributed seeds of four salt tolerant rice varieties to 162,237 farmers through government’s Agricultural Extension Department (DAE), local partner NGOs and local private seed producers in southern districts of Bangladesh. This year, in 2014, it is assumed that near about one million farmers are now cultivating these salt tolerant rice varieties in the boro season, and getting outstanding benefits to this end. Binadhan-8, Binadhan-10 and BRRI dhan55 got popularity among the farmers in the southern Bangladesh. This will help farmers to grow rice during the boro season in the southern part of Bangladesh, where one million hectares of farm land remain unused or less used during the dry season due to salinity intrusion. In the month of February-March-April, normally salinity reaches its peak in the southern coastal region and starts declining with the advent of monsoon. As these varieties are not a hybrid ones, so farmers can produce and store its seeds at their households level with maintaining its purity through roughing, drying and cleaning the seeds and keeping the same in airtight bags for next year cultivation.
    Although, Bangladesh is affected by the changed climate, but the country is now almost self-sufficient in rice production through new development of stress tolerant rice varieties and extension of such technologies. But there is still a need to increase production to feed the growing population which increases at the rate of 1:32 percent per annum. The economic development of the country is fundamentally based on agriculture; that’s why, it is necessary to enhance the growth of rice production through increasing land productivity to meet the increasing food demand for the vast population of the country as the country has serious land constraints. It is often argued that the future development of the country depends predominantly on the sustainable development of such stress tolerant rice varieties as well as extension and utilization of such varieties in stress-prone areas.

    The writer is Consultant, International Rice Research Institute (IRRI)

    Written by DR. M. G. NEOGI, collected from the Independent

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