Abstract The aim of this study was to evaluate two maize genotypes with contrasting drought-resistant phenotypic traits and to characterize how the plastic phenotypic traits contribute to yield potential under drought. The maize genotypes DKB 390 and BRS 1010 present contrasting yield traits in relation to drought and were treated with two water regimes: well-watered plant (WW, ≈−2 kPa) and water deficit (WD, ≈−100 kPa). In WD conditions, DKB 390 had a greater capacity to accumulate biomass in shoots than BRS 1010, indicating that shoot traits are important in increasing yield gain in the DKB 390 drought tolerant genotype and therefore, an important phenotypic trait for breeding for high yield in drought conditions. However, neither the total root dry mass nor its ratio to the shoot was related to increased yield. A large reduction in gas exchange and increased water use efficiency was observed in BRS 1010 compared to DKB 390. These traits are likely related to yield loss mainly due to decreased transpiration rate and stomatal conductance, which led to low photosynthetic rates and reduced growth. The root angle between genotypes was a constitutive trait and can be primarily responsible for the differences in yield. However, this trait in the DKB 390 genotype was affected by WD, as indicated by narrowing of the root angle. Our work describes the relationship between the narrow root growth angle in DKB 390 and its association with an increased capacity for water uptake in deeper regions, which may result in higher yield under drought. Regarding leaf anatomy we hypothesized that both osmotic adjustment and cell wall properties can influence anisotropic cell expansion under WD conditions and result in leaf tissue with higher yield potential in DKB 390. The high plasticity of vascular tissues and wide vessels could indicate a greater propensity for embolism and a slower response to WD, leading to yield loss in BRS 1010. The results of the phenotypic plasticity of maize genotypes show a negative relationship between high plasticity and yield potential and suggest that high plasticity can result in higher yield potential only when are present in phenotypic traits responsible for higher water uptake and drought tolerance.

中文翻译：

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抗旱玉米基因型的产量相关表型性状

摘要 本研究的目的是评估具有对比抗旱表型性状的两种玉米基因型，并描述可塑性表型性状如何影响干旱条件下的产量潜力。玉米基因型 DKB 390 和 BRS 1010 呈现出与干旱相关的对比产量性状，并用两种水源处理：充足浇水的植物（WW，≈-2 kPa）和缺水（WD，≈-100 kPa）。在 WD 条件下，DKB 390 在枝条中积累生物量的能力比 BRS 1010 大，这表明枝条性状对于增加 DKB 390 耐旱基因型的产量很重要，因此是干旱高产育种的重要表型性状使适应。然而，总根干质量及其与地上部的比率都与增加的产量无关。与 DKB 390 相比，在 BRS 1010 中观察到气体交换大幅减少和水分利用效率提高。这些性状可能与产量损失有关，主要是由于蒸腾速率和气孔导度降低，导致光合速率低和生长减少。基因型之间的根角是一种组成性状，是产量差异的主要原因。然而，DKB 390 基因型中的这种性状受 WD 的影响，如根角变窄所示。我们的工作描述了 DKB 390 中狭窄的根生长角度与其在较深区域吸水能力增加的关联之间的关系，这可能导致干旱条件下更高的产量。