Morpho-Biochemical Responses of Sugarcane Varieties to Salinity Stress During Formative Growth

Sugarcane, a key tropical cash crop, suffers significant yield losses in arid regions due to soil salinity stress. This study evaluated ten sugarcane varieties under normal and saline soils to identify salt-tolerant genotypes. Key morphological traits (shoot height, green leaf count, leaf area) and biochemical parameters (protein, amino acids, proline, chlorophyll) were investigated to assess salinity’s impact and guide selection for saline cultivation. The climatic parameters were monitored throughout the experiment. The study revealed that salinity reduced sugarcane's growth but enhanced its biochemical traits, including its protein, free amino acid, and proline contents. In terms of the mother shoot height, varieties CoSe 01424 and CoS 95255 exhibited strong tolerance to salinity, despite a 43.6 % reduction in the mother shoot height from an average of 106.6 cm to 60.1 cm under saline conditions. The average leaf count showed a slight decline from 9.8 to 9.2 under saline conditions. The leaf area decreased by 35.4 % under saline conditions, with CoSe 03234 maintaining the largest leaf size among the varieties. Biochemical analysis revealed that sugarcane grown in saline soil had a 6.6% higher average protein content (100.4 μg/g) compared to that grown in normal soil (94.1 μg/g). Varieties CoSe 03234, CoS 03251, and CoS 95255 exhibited increased protein levels under salinity, indicating enhanced protein accumulation under salt-affected conditions. Sugarcane in saline soil had, on average, 48% more free amino acids, with CoSe 03234 showing the highest levels. The proline levels increased in almost all the sugarcane varieties under salinity, with CoSe 03234 and CoS 03251 showing the highest accumulation. The chlorophyll content in sugarcane dropped by 20.6% in saline soil (0.257 μg/g) compared to normal soil (0.324 μg/g). CoSe 03251 had the highest chlorophyll content (0.451 μg/g) in the saline soil. This study identified salt-tolerant sugarcane varieties, CoSe 03234, CoS 03251, CoSe 01424, and CoS 95255, that support saline soil cultivation, higher yields, and sustainable agriculture.