Cultivar screening: assessment of plant growth, morphology, tipburn occurrence, and quality characteristics of six lettuce cultivars grown in a plant factory

Plants growing in a plant factory are no longer threatened by harsh environmental stresses, such as drought, salinity, low temperature, and diseases. The environmental factors in plant factories can be controlled to suit plant growth in order to obtain a high production or the desired quality. The plant varieties that are used in conventional farms may not suit the indoor cultivation anymore. Thus, the demand for exclusive plant species and cultivars is significantly increasing year by year. In this study, six different lettuce cultivars (two conventional and four new cultivars) were grown in a plant factory with LED light. The plant growth parameters and quality characteristics, such as fresh weight, leaf area, net photosynthetic rate, growth rate, tipburn occurrence, ascorbic acid, antioxidant and total phenol content were investigated and assessed among the six cultivars. The results show that one of the new cultivars achieved comparable fresh weight, higher antioxidant activity and total phenol content in leaf compared with that of the conventional varieties and significantly reduced tipburn occurrence. Another three new cultivars showed less production but favorable appearance and taste as well as the lowest tipburn occurrence. The data obtained in this research provide basis for practical applications and development of new lettuce cultivars in plant factories.