Climate smart rice for sustainable food security in Bangladesh

 

Bangladesh hosted a high-profile meeting recently at Dhaka organized by a worldwide climate action initiative named Global Commission on Adaptation (GCA). The Commission seeks to deliver concrete and meaningful action through a set of actions. GCA identified six areas of intervention for climate change adaptation in Bangladesh. Among all six action tracks, Agriculture and Food Security was one of the most important ones. As a participant in that meeting, I like to highlight some achievements and discuss other issues that should be considered for sustainable food security.

Among the six action tracks identified by GCA five priority actions for Bangladesh are a) Scale-up of investment in demand-led agricultural R&D, b) Facilitating smarter incentives and policy frameworks for transformative climate outcomes in agriculture, c) Scaled up access for small-scale agricultural producers to markets, finance, insurance, and social safety nets, d) Expanded coverage and use of climate- and weather-informed digital agricultural advisory services and e) Improved access and use of adaptation technologies, with a focus on agro ecological practices. Bangladesh is very much keen to implement all five priority action tracks. Bangladesh Rice Research Institute (BRRI), is of the key organization works directly to implement and achieve priority track number a, b, d, and e.

Food security is not a permanently achievable target. Rather, It needs continuous and persistent efforts to maintain and sustain for a long time. BRRI's research and development (R&D) has been oriented to achieve and sustain it. Since independence, our population has increased two and a half fold but rice production has increased more than three and a half fold which reflects the success story of our scientists, extension agents, farmers, and pro-agriculture government.

There are lots of climate change impacts on rice production. Considering all the climate vulnerabilities BRRI has so far developed a total of 24 stress-tolerant rice varieties of which 11 are saline tolerant, 3 submergence tolerant, 3 drought-tolerant, 4 cold-tolerant, 2 tidal submergences tolerant, 1 semi-deep water, and 1 dual (Sal+Sub) tolerant. Most importantly all the 24 stress-tolerant varieties developed during the last 11 years contributed a lot to boost up rice production in the country. Many more advanced breeding lines have been screened to identify materials tolerant to different abiotic stresses like salinity, cold, high temperature, flash flood, etc which are in the pipeline to release soon. Using climate-smart varieties and with the combined efforts of farmers, rice scientists, extension personnel, and the Government of Bangladesh have enabled the country with a surplus of about 4 MT of rice. Our population is increasing by 2.2 million per year. With the synergy of population increase, rice production needs to increase by 0.35 MT year-1. But we are increasing rice production @0.6 MT year-1 during 2009-19.

The crop growing environments of Bangladesh are very much diverse, varying from the drought-prone high lands in the north-west, the flood-affected central region, the coastal saline zone in the south, Haor in the north-east, and Hills in the south-east. The major stress-prone environment is salinity prone coastal zone constituting about 105.6 million hectares. In addition to salinity, water stagnation is another problem in that eco-system. Challenge is to increase productivity through multiple climate resilient interventions.

Addressing that challenge a total of 11 salinity tolerant varieties have been developed for the wet and dry season. Of them, BRRI dhan47 and BRRI dhan67 are the two promising salt-tolerant varieties for the dry season having 6-8 dS/m salinity tolerance during the whole life cycle and 4.5 to 7.5 t/ha yield potential. Out of 105.6 million hectares of the saline area, about 35% area is covered by BRRI released salt-tolerant varieties, which contributed to 10 percent of total rice production. For Example of recent success, Moharajpur, a village of Koyra, Khulna is one of the extreme climate-vulnerable areas in the coastal zone which remained fallow in the dry season. But salinity tolerant variety BRRI dhan67 has been successfully cultivated last year. Farmers are very happy as they got >7.0 t/ha yield/ha. Importantly, this type of horizontal expansion of MV rice has been taken place with a huge impact on the livelihood of marginal farmers.

Drought is a problem in rice cultivation in both vegetative and reproductive stages in >3.0 mha areas. Drought tolerant wet season varieties developed like BRRI dhan56, BRRI dhan66, and BRRI dhan71. Of them, BRRI dhan71 is getting quick popularity in North-Western Barind Tracts having 5.5-6.5 t/ha yield potential with shorter growth duration of 115 days. Out of the total drought area, 12% comes under rice cultivation which contributing 8 percent to our total production. Due to the decrease of upstream flow and climate change, char land areas are increasing. Dry direct seeded aerobic rice varieties are one of the good adaptation options in this unfavorable environment. However, some deep-rooting crops like maize, pumpkin; Chili, etc. are well adapted and are being scaled up.

BRRI released submergence tolerant verities were grown in 26 percent submerge areas which contribute 9 percent of total production. About 5,700 hectares of land are now under rice cultivation using BRRI released dual tolerant (Sal+Sub) varieties which were never been rice cultivable. However, the production contribution of stress-tolerant varieties is about 10% in normal year but about 80% yield advantage in stress year. Noticeably, stress-tolerant varieties contribute around 1525 million USD yearly.

In Bangladesh, a total of>2.0 mha rice areas are affected by flash flood submergence. It may affect complete damage to the crop plants. Wet season rice is generally affected during vegetative stages. Dry season (Boro) rice is also affected at the reproductive stages by the early flash flood in the Hoar areas which is a low-lying basin in the North-Eastern part. 03 flash flood-tolerant varieties like BRRI dhan51, 52, and 79 have been developed having 2-3 weeks of complete inundation tolerance and can produce more than 80% yield benefits under stress conditions.

Tidal flood-prone eco-system covers 0.8 Mha in the Southern coastal region. Generally, low yielding indigenous cultivars are grown there. BRRI has developed 2 varieties BRRI dhan76 and 77 having adaptation capacities in that environment with 1.5-2.0 t/ha yield advantage over local cultivars and create a significant impact on the farmers.

During Boro season in Haor areas, an early flash flood occurs in the 2nd week of April ('Boishakhi dhal') affect Boro rice at the ripening stage. Flash flood rarely occurs in the 3rd or 4th week of March ('Choitali dhal'), caused severe damage in different years at the reproductive stages. Short duration and reproductive stage cold-tolerant Boro varieties are the prime need for the Haor farmers. BRRI has initiated cutting edge breeding technologies to develop short duration cold tolerant variety for them.

In Bangladesh >2.0 mha areas are affected by different scales of cold injury. Severe cold in mid-December to early January hampers seedling rising in the North-Western region. Seeding with water receding in the Haor ecosystem in October causes severe sterility due to cold injury (<18-20°C) in last January to February. Earlier developed 4 cold-tolerant varieties have only tolerance during the seedling stage. The effort for developing reproductive stage cold-tolerant varieties for Haor areas is in progress at BRRI utilizing modern breeding strategies.

North-western belt of Bangladesh is affected by heat which is a problem in rice production in short duration T. Aman, upland Aus and late Boro season. Heat causes panicle deformation and spikelet sterility. Breeding for developing heat-tolerant varieties is in the advanced stage at BRRI. These are the major interventions by BRRI concerning climate change adaptation in Bangladesh.

Declination of groundwater @0.64 m/year is another challenge in the northern part of the country during Boro season. This is happening due to uneven rainfall, the drying-up of rivers, and the use of excess underground water for crop cultivation. To combat this critical challenge, BRRI released a low input variety for that part named BRRI dhan69 which can give significant yield with less input like- fertilizer and irrigation.

Bangladesh has the potential to boost rice production and export, which can contribute to the national economy. Due to increased intensities of climate vulnerabilities, targeted breeding is essential to accommodate the diverse environments and the level of stress tolerance needs to be increased. The development and dissemination of stress-tolerant, high-yielding, early-maturing, and nutrient-rich varieties will further boost rice production in the country. BRRI is using and utilizing modern biotechnological tools like tissue culture, genetic engineering for developing diverse stress-tolerant varieties.


M Abdul Momin, Senior Liaison Officer, BRRI & Ph.D. Fellow, Department of AEIS, Sher-e-Bangla Agricultural University, Dhaka.