Soybean [Glycine max (L.) Merril] is one of the main crops produced worldwide, and on-farm yields have increased considerably in the last decades in Brazil. We evaluated the genetic gain for agronomic, phenological, and end-use quality traits in 29 cultivars in the South Region, and in 38 cultivars in the Midwest Region in Brazil, released from 1966 to 2011. Field trials were conducted in Macroregions 1, 2, and 4, in 2016–2017, 2017–2018, and 2018–2019 crop seasons. The best linear unbiased predictors (BLUP) of the cultivars were obtained for each trait using a linear model. The BLUPs were regressed with the year of release using linear and quadratic regression models. The rates of genetic gain for seed yield ranged from 11.98 to 15.31 kg ha^–1 yr^–1 (0.33 to 0.42% yr^–1) in the South Region, and from 13.58 to 21.84 kg ha^–1 yr^–1 (0.47 to 0.77% yr^–1) in the Midwest Region. New cultivars presented taller plants and more seed oil content, oil and protein yield, and lower seed weight, days to flowering, days to maturity, and seed protein content than old cultivars in the South Region, although with differences between the Macroregions. In the Midwest Region, new cultivars showed higher seed oil content, oil and protein yield, and lower bottom pod height and seed protein content than old cultivars. Our results showed that breeding programs have been efficient to improve soybean yield and other traits across the years, without yield plateaus in sight.

中文翻译：

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巴西大豆遗传改良：南部和中西部地区

大豆 [ Glycine max (L.) Merril] 是世界范围内生产的主要作物之一，过去几十年巴西的农场产量大幅增加。我们评估了 1966 年至 2011 年间发布的巴西南部地区 29 个品种和巴西中西部地区 38 个品种的农艺学、物候学和最终用途品质性状的遗传增益。田间试验在宏观区域 1、2 进行和 4，在 2016-2017、2017-2018 和 2018-2019 作物季节。使用线性模型为每个性状获得品种的最佳线性无偏预测因子 (BLUP)。使用线性和二次回归模型对 BLUP 与发布年份进行回归。种子产量的遗传增益率为 11.98 至 15.31 kg ha ^–1 yr ^–1（0.33 到 0.42% yr ^–1）在南部地区，从 13.58 到 21.84 kg ha ^–1 yr ^–1（0.47 到 0.77% yr ^–1）在中西部地区。与南部地区的老品种相比，新品种的植株更高，种子含油量、油脂和蛋白质产量更高，种子重量、开花天数、成熟天数和种子蛋白质含量更低，尽管大区之间存在差异。在中西部地区，新品种的种子含油量、油脂和蛋白质产量高于老品种，而底荚高度和种子蛋白质含量较低。我们的结果表明，育种计划多年来一直有效地提高大豆产量和其他性状，产量稳定期还未出现。