New Rice Lines Promise Bigger Harvests with Less Water and Labour.

Oct 2025 : Scientists from the International Rice Research Institute (IRRI) and the Indian Council of Agricultural Research (ICAR) have developed new rice lines suited for dry direct-seeded rice (DDSR), a method in which seeds are planted directly into dry soil rather than flooded paddy. This approach reduces water use and labour costs, which are major challenges for farmers.

The research was carried out with the Indian Council of Agricultural Research (ICAR) with support from India’s Department of Biotechnology, with the IRRI-ICAR work plan further supports the work.

Dry direct-seeded rice (Oryza sativa L.; DDSR) is an alternative to transplanted puddled rice (TPR) that enhances water use efficiency and mechanisation and reduces labour, greenhouse gas (GHG) emissions, and global warming potential (GWP).

To address the limited availability of DDSR-suitable varieties, the research team initiated a genomic-assisted breeding program to develop such varieties by combining 19 DDSR and biotic stress-related genes / quantitative trait loci (QTLs), that is, anaerobic germination (qAG9.1, qAG9.2), early emergence (qEMM11.1, qEMM3.1), early vegetative vigour (qEVV9.1), root hair density (qRHD1.1), nodal root count (qNR5.1), culm strength (qCS1.1), lodging resistance (qLDG3.1, qLDG4.1), grain yield (qGYDS1.1, qGYDS6.1, qGYDS9.1, qGYDS10.1), gall midge (Gm4, Gm8), blast (Pi9), and brown plant hopper (Bph3, Bph17), using 11 donor parents in MTU 1010 and IR91648-B-89-B genetic background.

From over 150 introgression lines (ILs), 48 carried 7–15 targeted genes / QTLs. Genotyping with the 1k-RiCA SNP array further revealed 2–49 non-targeted genes / QTLs per IL associated with different biotic, abiotic, yield, and quality-related traits. The ILs the research team evaluated in DDSR and TPR conditions over 2 years, and the introgressed traits the research team genotypically and phenotypically validated.

The research team observed a positive correlation bet the research teamen the yield performance of developed ILs in both conditions. The top 10 ILs yielded an average of 5756 kilograms per hectare in DDSR and 5665 kilograms per hectare in TPR conditions. Of the four nominated best performing ILs, two ILs are in the advanced stage of the national varietal release program, and many more ILs are in the nomination process for variety release. These ILs are also potential pre-breeding resources for DDSR-suitable varieties in further breeding programs.

The new lines combine 19 important traits, including anaerobic germination, higher yield, stronger seedlings, resistance to lodging, and protection against pests and diseases such as blast, brown planthopper, and gall midge. These improvements were developed into MTU 1010, one of India’s most widely grown rice varieties. The traits were also added into IR 91648-B-89-B, an elite breeding line that carries a major QTLs for rice grain yield under reproductive-stage drought stress in the background of Swarna, another mega variety popular among Indian farmers.

In field trials, the best performers produced up to 5.7 tons per hectare under DDSR and 5.6 tons under traditional flooded fields. This is about 15% to 16% higher than the yield of their parent varieties.

“This is one of the few successful efforts to combine a wide set of DDSR traits into elite rice backgrounds”, said Regional Breeding Lead-South Asia, Dr. Vikas K. Singh. “It shows that popular transplanted varieties can be redesigned for direct-seeded systems without losing yield or grain quality”. Several of the new lines are already in India’s varietal release pipeline, with two under advanced evaluation trials.

Team Maverick