Low soil nitrogen (low N) threatens maize production in sub-Sahara Africa (SSA). We examined the mode of gene action conditioning grain yield of intermediate maturing inbreds and evaluated lines in hybrid combinations for high yield, stability and tolerance to low N. Thirty-two sets of inbreds were crossed to three elite testers (87036, 1368 and 9071) to generate 96 F1 hybrids. The testcrosses plus four hybrid checks were evaluated under low (30 kg/ha) and high (90 kg/ha) N environments at three locations for 2 years in Ghana. Significant general combining ability (GCA) and specific combining ability (SCA) effects were detected for grain yield and most measured traits across test environments, indicating that both additive and non-additive gene action governed the inheritance of the traits. GCA effects were greater than SCA effects, indicating that most traits were controlled predominantly by additive gene action and that inbreds with positive significant GCA effects for grain yield and other traits would contribute favourable alleles to progenies across environments. Hybrid CZL 0001 × 9071 possessed high GY, increased EPP, desirable EHT and PLHT and was the highest yielding under each of two research conditions. Significant genetic correlations were observed between GY and PLHT, EPP, EHT, CA and PA implying that improvement of these traits would lead to significant gains in grain yield under low-N conditions. Hybrids CLWN 247 × 9071, ZM523B-29-2-1-1-B*6 × 9071, TZD II 68 × 1368 and P43SCRq Fs100-1-1-8 × 9071 were high-yielding, stable and low-N tolerant and should be tested on-farm and commercialized.

中文翻译：

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低氮和最佳环境下耐低氮玉米中间自交系的组合能力和试交性能

低土壤氮（低氮）威胁着撒哈拉以南非洲（SSA）的玉米生产。我们检查了中间成熟自交系的基因作用调节谷物产量的模式，并评估了杂交组合中的系的高产、稳定性和对低氮的耐受性。将 32 组自交系与三个优良测试者（87036、1368 和 9071）杂交产生 96 F1杂种。在加纳的三个地点，在低（30 公斤/公顷）和高（90 公斤/公顷）N 环境下对测试杂交和四次杂交检查进行了为期 2 年的评估。在整个测试环境中检测到谷物产量和大多数测量的性状的显着一般配合力 (GCA) 和特定配合力 (SCA) 效应，表明加性和非加性基因作用都控制着性状的遗传。GCA 效应大于 SCA 效应，表明大多数性状主要受加性基因作用控制，并且对谷物产量和其他性状具有显着正显着 GCA 效应的自交系将为跨环境的后代提供有利的等位基因。杂种 CZL 0001 × 9071 具有高 GY、增加的 EPP、理想的 EHT 和 PLHT，并且在两种研究条件下的产量最高。在 GY 和 PLHT、EPP、EHT、CA 和 PA 之间观察到显着的遗传相关性，这意味着这些性状的改善将导致在低氮条件下粮食产量显着增加。杂交种 CLWN 247 × 9071、ZM523B-29-2-1-1-B*6 × 9071、TZD II 68 × 1368 和 P43SCRq Fs100-1-1-8 × 9071 具有高产、稳定和耐低氮的特点。应在农场进行测试并商业化。