Maize (Zea mays L.) grain yield is severely constrained by drought and this study was conducted to assess gains in grain yield and other traits of released maize cultivars. Twenty-three maize cultivars plus a check were evaluated under drought and well-watered conditions at Zaria and Kadawa during 2015/2016 and 2016/2017 dry seasons. The 24 cultivars were evaluated using 6 x 4 lattice design with three replications. Genotypes differed significantly for all measured traits except anthesis-silking interval (ASI), husk cover, and number of ears per plant under drought, and ASI, husk cover, and ear aspect under well-watered conditions. Under drought, grain yield ranged from 2251 kg ha−1 for SAMMAZ 31 to 4938 kg ha−1 for SAMMAZ 19, with a genetic gain of 1.93% yr−1. Under well-watered conditions, grain yield varied from 3082 kg ha−1 for SAMMAZ 37 to 5689 kg ha−1 for SAMMAZ 51, with the same genetic gain found under drought conditions. Grain yield reduction as a result of drought was 28.4% and performance under drought predicted performance under well-watered conditions better than vice versa with regression coefficient value of 0.8. Grain yield had significant correlations with all measured traits under both water conditions, except for husk cover, plant and ear heights under drought. Our data revealed that substantial genetic gains have been made in breeding for high grain yield cultivars under drought and well-watered conditions over a period of 16 years in Nigeria.

中文翻译：

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在干旱和良好浇水条件下释放的玉米 (Zea mays L.) 品种的谷物产量增加

玉米（玉米L.) 谷物产量受到干旱的严重限制，本研究旨在评估已释放玉米品种的谷物产量和其他性状的收益。在 2015/2016 年和 2016/2017 年旱季期间，在 Zaria 和 Kadawa 在干旱和水分充足的条件下评估了 23 个玉米品种和一个检查。使用 3 个重复的 6 x 4 格子设计对 24 个品种进行了评估。除花丝间隔 (ASI)、稻壳覆盖率和干旱条件下每株植物的穗数以及水分充足条件下的 ASI、稻壳覆盖率和穗长外，所有测量性状的基因型均存在显着差异。干旱条件下，粮食产量为 2251 公斤公顷-1SAMMAZ 31 至 4938 kg ha-1对于 SAMMAZ 19，遗传增益为 1.93% 年-1. 在水分充足的条件下，粮食产量从 3082 公斤公顷不等-1SAMMAZ 37 至 5689 kg ha-1对于SAMMAZ 51，在干旱条件下具有相同的遗传增益。干旱导致的粮食减产为 28.4%，干旱条件下的表现预测水分充足条件下的表现优于反之亦然，回归系数值为 0.8。谷物产量与两种水分条件下的所有测量性状均具有显着相关性，但干旱条件下的壳盖、植物和穗高除外。我们的数据显示，在过去 16 年的时间里，尼日利亚在干旱和水分充足的条件下培育高产品种取得了可观的遗传收益。