Knowledge of the physiological mechanisms in saline environment may boost sugarcane breeding programmes targeting abiotic stresses. Our hypothesis is that the physiology of Saccharum genotypes responds differently under salt stress. Thus, the objective of the study was to evaluate the physiological performance of Saccharum complex genotypes grown under presence and absence of saline stress. The experimental design used was randomized blocks arranged in a 32 × 2 factorial scheme (32 genotypes × 2 salinity levels). The presence of salinity provided higher mean values for photosynthetic rate in genotypes G4, G18, G22, G25 and G29 compared with the environment without salinity, with mean values (17.26, 21.49, 24.22 and 26.19 µmol CO₂m⁻²s⁻¹), respectively, for internal CO₂ concentration in G2, G6, G9, G14, G17, G19, G23 and G29, with mean values (323.45, 399.64, 386.88, 412.14, 366.31, 250.48, 379.10 and 380.75 µmol CO₂ mol air⁻¹), respectively, for transpiration in G18, G24, G25 and G29, with mean values (5.05, 3.30, 4.39 and 4.01 mmol H₂O m⁻²s⁻¹), respectively, and for chlorophyll content in G3, G5, G6, G8, G10, G13, G20, G22, G23, G25, G31 and G32, with mean values (34.18, 43.01, 38.08, 32.38, 37.09, 37.18, 32.47, 38.38, 38.04, 36.95 and 33.32 SPAD units) respectively. Genotypes that under salt stress increase their physiological performance demonstrate superiority over others and should be considered in breeding programmes. Photosynthesis and transpiration is the most adequate combination for screening, but the spad index is the most viable tool because of its ease of determination and cost.

中文翻译：

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盐胁迫对甘蔗复合基因型生理的影响

了解盐碱环境中的生理机制可能会促进针对非生物胁迫的甘蔗育种计划。我们的假设是Saccharum基因型的生理学在盐胁迫下的反应不同。因此，该研究的目的是评估在存在和不存在盐胁迫的情况下生长的甘蔗复合基因型的生理性能。使用的实验设计是按 32 × 2 因子方案（32 基因型 × 2 盐度水平）排列的随机区组。与没有盐分的环境相比，盐分的存在为基因型 G4、G18、G22、G25 和 G29 的光合速率提供了更高的平均值，平均值为（17.26、21.49、24.22 和 26.19 µmol CO ₂ m ^-2 s^-1 )，分别为 G2、G6、G9、G14、G17、G19、G23 和 G29 中的内部 CO ₂浓度，平均值为 (323.45、399.64、386.88、412.14、366.31、250.48、379.10 和 380.75 µmol CO ₂  mol air ^-1 )，分别用于 G18、G24、G25 和 G29 的蒸腾作用，平均值为 (5.05、3.30、4.39 和 4.01 mmol H ₂ O m ^-2 s ^-1)，分别为 G3、G5、G6、G8、G10、G13、G20、G22、G23、G25、G31 和 G32 中的叶绿素含量，平均值为 (34.18, 43.01, 38.08, 32.38, 37.09, 37.18, 32.47 、38.38、38.04、36.95 和 33.32 SPAD 单位）。在盐胁迫下增加其生理性能的基因型表现出优于其他基因型，应在育种计划中予以考虑。光合作用和蒸腾作用是筛选最合适的组合，但 spad 指数是最可行的工具，因为它易于确定且成本低。