One of the main challenges of breeding programs is to identify superior genotypes from a large number of candidates. By gradually increasing the frequency of favorable alleles in the breeding population, recurrent selection improves the population mean for target traits, increasing the chance to identify promising genotypes. In rice, population improvement through recurrent selection has been used very little to date, except in Latin America. At Embrapa (Brazilian Agricultural Research Corporation), the upland rice breeding program is conducted in two phases: population improvement followed by product development. In this study, the CNA6 population, evaluated over five cycles (3 to 7) of selection, including 20 field trials, was used to assess the realized genetic gain. A high rate of genetic gain was observed for grain yield, at 215 kg.ha⁻¹ per cycle or 67.8 kg.ha⁻¹ per year (3.08%). The CNA6 population outperformed the controls only for the last cycle, with a yield difference of 1128 kg.ha⁻¹. An analysis of the product development pipeline, based on 29 advanced yield trials with lines derived from cycles 3 to 6, showed that lines derived from the CNA6 population had high grain yield, but did not outperform the controls. These results demonstrate that the application of recurrent selection to a breeding population with sufficient genetic variability can result in significant genetic gains for quantitative traits, such as grain yield. The integration of this strategy into a two-phase breeding program also makes it possible to increase quantitative traits while selecting for other traits of interest.

育种计划的主要挑战之一是从大量候选基因中识别出优异的基因型。通过逐渐增加育种群体中有利等位基因的频率，循环选择提高了目标性状的群体平均值，增加了识别有希望的基因型的机会。在水稻方面，除了拉丁美洲以外，迄今为止，通过轮回选择来改良种群的方法还很少被采用。在 Embrapa（巴西农业研究公司），旱稻育种计划分两个阶段进行：种群改良和产品开发。在本研究中，CNA6 群体经过五个选择周期（3 至 7 个）（包括 20 次现场试验）的评估，用于评估已实现的遗传增益。观察到谷物产量的遗传增益很高，每个周期 215 kg.ha ^-1或每年67.8 kg.ha ^{-1 (3.08%)。}CNA6群体仅在最后一个周期表现优于对照，产量差异为1128 kg.ha ^-1。对产品开发渠道的分析基于 29 个先进的产量试验，其中包括来自第 3 至 6 个周期的品系，表明源自 CNA6 群体的品系具有高谷物产量，但没有优于对照。这些结果表明，对具有足够遗传变异性的育种群体应用轮回选择可以导致数量性状（例如谷物产量）的显着遗传增益。将该策略整合到两阶段育种计划中还可以在选择其他感兴趣的性状的同时增加数量性状。