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Rice production needs to increase in the future in order to meet increasing demands. The development of new improved and higher yielding varieties more quickly will be needed to meet this demand. However, most rice breeding programmes in the world have not changed in several decades. In this article, we revisit the evidence in favour of using rapid generation advance (RGA) as a routine breeding method. We describe preliminary activities at the International Rice Research Institute (IRRI) to re-establish RGA on a large scale as the main breeding method for irrigated rice breeding. We also describe experiences from the early adoption at the Bangladesh Rice Research Institute. Evaluation of RGA breeding lines at IRRI for yield, flowering time and plant height indicated transgressive segregation for all traits. Some RGA lines were also higher yielding than the check varieties. The cost advantages of using RGA compared to the pedigree method were also empirically determined by performing an economic analysis. This indicated that RGA is several times more cost effective and advantages will be realized after 1 year even if facilities need to be built. Based on our experience, and previous independent research empirically testing the RGA method in rice, we recommend that this method should be implemented for routine rice breeding in order to improve breeding efficiency.

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Traditional approaches for introducing improved rice varieties to farmers have demonstrated significant impact in favourable ecosystems in Asia, but with limited success in unfavourable ecosystems, as in saltaffected areas. Developing rice varieties with wider adaptation and broader tolerance of prevailing stresses is more viable for these areas, where abiotic stresses are particularly variable and complex, and growing conditions are too risky to persuade farmers to invest in inputs. The Challenge Program on Water and Foodsupported project (Project No 7) emphasizes the development and deployment of high-yielding, salt-tolerant rice varieties for coastal saline (Bangladesh, Vietnam and India), inland saline (Egypt and Iran) and sodic soils (India), where rice-based farming systems are being practised. Mostly, a superior performance of genotypes under experimental conditions does not guarantee their acceptance by farmers, and occasionally farmers reject genotypes that yield well if they do not satisfy their quality preferences. In view of this, a participatory varietal selection (PVS) approach, in which farmers participate in varietal screening and adaptation testing, was followed to accelerate the adoption of salt-tolerant varieties. The International Network for Genetic Evaluation of Rice (INGER), a global germplasm-testing platform coordinated by IRRI, is being used for the exchange of germplasm through the International Rice Soil Stress Tolerance Observational Nursery (IRSSTON). Promising lines were selected through PVS trials and some were released or nominated for release as varieties. Participating farmers increased their paddy yield from <2 t/ha to >3.5 t/ha, which encouraged neighbouring farmers to adopt these new varieties. Recently, BRRI dhan 47 was released as the first salttolerant variety for the boro (dry) season in the coast of Bangladesh. Progress has been made in reclaiming inland saline and sodic soils at Lucknow and Faizabad in India and CSR30, an aromatic fine-grain, salt tolerant variety, has recently become popular among farmers, besides other varieties. Proper management options for these salt-tolerant, high-yielding varieties have been developed and validated simultaneously in PVS trials. Introducing PVS has increased the adoption rate and helped to solicit systematic feedback from farmers, which has been a major guiding force in devising breeding strategies and in developing customized breeding materials.

The importance of including farmers in targeted breeding and participatory variety selection (PVS) to ensure the adoption of high-yielding varieties was demonstrated in the coastal wetlands of the Ganges-Brahamputra Delta of southern Bangladesh. Five sites were selected for conducting 'mother and baby' trials. About 245 salt-tolerant genotypes from the International Rice Research Institute (IRRI) and Bangladesh Rice Research Institute (BRRI) were divided into three mother trial sets of 72 genotypes for the wet ('T. aman') season, 76 for the irrigated dry ('boro') season and 85 for the dry direct-seeded ('aus') season. During the PVS trials, farmers chose the best one or two genotypes from mother trials to grow in their fields as baby trials. Through local non-government organizations (NGOs: Proshika, Gurpukur, Uttaran and Sushilan), a total of 199 resource-poor farmers, including 15 women, selected 34 genotypes for the three seasons. Farmers were given 500 g of seeds of each selection for baby trials under their own management. For the 'boro' season, IR64401-2B-14-1-1, IR60483-2B-17-2-1-2 and BR5777-4-2-1-HR2 were selected. For the 'T. aman' season, IR66401-2B-14-1-1 was preferred for its short growth duration and high yield. For the direct-seeded 'aus' season, three genotypes, IR72593-B19-2-3-1, IR64419-3B-12-2 and IR64419-3B-4-3, were identified because of their short growth duration. IR63307-4B-4-3 was identified through PVS trials and was released as BRRI dhan 47 for commercial use in coastal Bangladesh in 2006. Out of 53 landraces collected from these coastal areas, four genotypes - Capsule, Ashfal, Ashfal balam and Chikiram Patnai - were identified as new salt-tolerant donors. Moreover, 16 modern genotypes, including four varieties from Vietnam, were identified as tolerant of salt stress at the seedling stage (EC of 12 dS/m). OM1490 had short duration similar to that of BRRI dhan 28, a popular dry-season variety, but produced more than 1 t/ha extra grain yield. In addition, OM2718, AS996 and BR7109-5R-4 had growth duration similar to BRRI dhan 47 and a yield advantage of more than 1 t/ha. In contrast to BRRI dhan 47, these new lines were non-shattering. Adding ash along with the recommended N, P, K and Zn at 120, 80, 30 and 0.5 kg/ha, respectively, did not increase the grain yield of all varieties in saline areas because of the high soil potassium saturation (>20%). Moreover, farmers in these areas had been growing salt-sensitive rice varieties successfully by practising: (i) high transplanting rates of 5-6 seedlings/hill; (ii) draining the field, followed by irrigation with fresh water from shallow tube wells; and (iii) shifting the shallow tube-well installation after 3-5 years to tap less salt water. Monitoring of the salinity in nearby rivers (Retna) suggested the possibility of their use for rice irrigation from June to the middle of February, when salinity was mostly below 4 dS/m, with potential for an additional dry-season crop.