Maize (Zea mays L.) is susceptible to salinity but shows genotypic variation for salt tolerance. How maize genotypes with contrasting root morphological traits respond to salt stress remains unclear. This study assessed genotypic variation in salinity tolerance of 20 maize genotypes with contrasting root systems exposed to NaCl for 10 days (0, 50 mM or 100 mM NaCl, added in four increments every other day from 14 days after transplanting, DAT) in a semi‐hydroponic phenotyping system in a temperature‐controlled greenhouse. Considerable variation was observed for each of the 12 measured shoot and root traits among the 20 genotypes under NaCl treatments. Salt stress significantly decreased biomass production by up to 54% in shoots and 37% in roots compared with the non‐saline control. The 20 genotypes were classified as salt‐tolerant (8 genotypes), moderately tolerant (5) and salt‐sensitive (7) genotypes based on the mean shoot dry weight ratio (the ratio of shoot dry weight at 100 mM NaCl and non‐saline control) ± one standard error. The more salt‐tolerant genotypes (such as Jindan52) had less reductions in growth, and lower shoot Na⁺ contents and higher shoot K⁺/Na⁺ ratios under salt stress. The declared salt tolerance was positively correlated with shoot height, shoot dry weight and primary root depth, and negatively correlated with shoot Na⁺ content at 100 mM NaCl. Primary root depth is critical for identifying salt responsiveness in maize plants and could be suggested as a selection criterion for screening salt tolerance of maize during early growth. The selected salt‐tolerant genotypes have potentials for cultivation in saline soils and for developing high‐yielding salt‐tolerant maize hybrids in future breeding programmes.

中文翻译：

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具有深根系统的玉米基因型在早期生长期间比具有浅根系统的基因型对盐胁迫的耐受性更好

玉米（玉米）L.）对盐分敏感，但显示出耐盐性的基因型变异。根系形态特征相反的玉米基因型如何应对盐胁迫尚不清楚。这项研究评估了半根暴露于NaCl 10天（0、50 mM或100 mM NaCl，从移植后第14天起，每隔一天从DAT中每隔4天添加一次）的20种玉米基因型的耐盐性的基因型变异。温控温室中的水培表型系统。在NaCl处理下，对20个基因型中的12个实测茎和根性状中的每一个均观察到了显着的变化。与非盐胁迫相比，盐胁迫显着降低了新梢的生物量产量，最高降低了54％，根部降低了37％。这20个基因型被归为耐盐（8个基因型），基于平均枝干重量比（100 mM NaCl和非盐溶液对照下的枝干重量比）±1个标准误差的中等耐性（5）和盐敏感（7）基因型。耐盐性更高的基因型（例如金丹52）的生长减缓幅度较小，而芽Na含量较低⁺含量和盐胁迫下较高的芽K ⁺ / Na ⁺比。宣布的耐盐性与苗高，苗干重和初生根深度呈正相关，而与100 mM NaCl时苗Na ⁺含量呈负相关。初生根深度对于鉴定玉米植株的盐分响应能力至关重要，可以作为筛选玉米早期生长期耐盐性的选择标准。选定的耐盐基因型具有在盐渍土壤中种植和在未来的育种计划中开发高产耐盐玉米杂交种的潜力。