SpeedyPaddy: a revolutionized cost-effective protocol for large scale offseason advancement of rice germplasm

Abstract Background Improving the rate of genetic gain of cereal crop will rely on the accelerated crop breeding pipelines to allow rapid delivery of improved crop varieties. The laborious, time-consuming traditional breeding cycle, and the seasonal variations are the key factor restricting the breeder to develop new varieties. To address these issues, a revolutionized cost-effective speed breeding protocol for large-scale rice germplasm advancement is presented in the present study. The protocol emphasises on optimizing potting material, balancing the double-edged sword of limited nutritional dose, mode and stage of application, plant density, temperature, humidity, light spectrum, intensity, photoperiod, and hormonal regulation to accelerate rice growth and development. Results The plant density of 700 plants/m 2, cost-effective halogen tubes (B: G: R: FR-7. 0: 27. 6: 65. 4: 89. 2) with an intensity of ∼ 750–800 µmol/m 2 /s and photoperiod of 13 h light and 11 h dark during seedling and vegetative stage and 8 h light and 16 h dark during reproductive stage had a significant effect (P < 0. 05) on reducing the mean plant height, tillering, and inducing early flowering. Our results confirmed that one generation can be achieved within 68–75 days using the cost-effective SpeedyPaddy protocol resulting in 4–5 generations per year across different duration of rice varieties. The other applications include hybridization, trait-based phenotyping, and mapping of QTL/genes. The estimated cost to run one breeding cycle with plant capacity of 15, 680 plants in SpeedyPaddy was 2941 including one-time miscellaneous cost which is much lower than the advanced controlled environment speed breeding facilities. Conclusion The protocol offers a promising cost-effective solution with average saving of 2. 0 to 2. 6 months per breeding cycle with an integration of genomics-assisted selection, trait-based phenotyping, mapping of QTL/genes, marker development may accelerate the varietal development and release. This outstanding cost-effective break-through marks a significant leap in rice breeding addressing climate change and food security.