Growth and physiology of lettuce (Lactuca sativa L.) cultivars under different growing systems

Abstract

Agriculture in the present day faces a variety of challenges such as rise in population, decrease in arable land and rapid urbanization. Hence, adoption of newer technologies is a need of the hour and there has been shift from conventional cultivation towards protected cultivation, particularly soilless cultivation. We hypothesis that the physiological parameters of the crop are influenced by different growing systems and this in turn affects the growth and yield. In our study, three loose leaf lettuce cultivars were used to evaluate three growing systems, viz., soil based growing system, aggregate media hydroponics growing system with cocopeat as substrate and nutrient film technique (NFT). The lettuce grown in NFT was found superior compared to other systems. The biophysical parameters like photosynthetic rate, transpiration rate and stomatal conductance were recorded highest in NFT with 18.57 µmol CO₂ m⁻² s⁻¹, 6.944 mmol H₂O m⁻² s⁻¹ and 0.647 mmol CO₂ m⁻² s⁻¹ respectively at 45 DAT while in soil based system, photosynthetic rate, transpiration rate and stomatal conductance were 13.66 µmol CO₂ m⁻² s⁻¹, 3.409 mmol H₂O m⁻² s⁻¹ and 0.406 mmol CO₂ m⁻² s⁻¹ respectively. Among the different growing systems, maximum yield was also found to be in NFT system (260.66 g/plant) whereas minimum was in soil based growing system (123.92 g/plant).. In summary, our results indicate that soilless system especially NFT can be adopted as the growing system as it improves yield, through refining the physiological attributes. This conclusion is of great significance to our present knowledge on influence of soilless growing system on crops.