Effect of LED Light Intensity on Seedling Quality and Tuber Production of Potato Stem Cuttings Grown in a Closed-Type Plant Production System

Abstract

This study was performed to establish light intensity conditions for producing stem cuttings for aeroponic systems suitable for seed potato production using a closed-type plant production system. Shoot tip cultured plantlets of ‘Sumi’ and ‘Chubaek’ potato (Solanum tuberosum L.) were acclimatized, cuttings were collected, and stem cuttings were planted. The seedlings were raised for 40 days at different LED light intensities (60, 120, 180, and 240 μmol·m-2·s-1), and were cultivated in an aeroponic system for 80 days. When stem cuttings were raised at 60 μmol·m-2·s-1 LED light intensity, the plant height was the longest, at 17.3 cm for ‘Sumi’ and 16.1 cm for ‘Chubaek’, and the number of nodes was the highest in both cultivars. The higher light intensities, produced smaller plants with fewer nodes. The leaf areas, SPAD values, and Fv/Fm values differed slightly between cultivars. The fresh weight of stem cuttings, and the production rate of healthy stem cuttings were the highest at 60 μmol·m-2·s-1. In the aeroponic system, seedlings raised at 60 μmol·m-2·s-1 with LED light intensity showed a difference between the cultivars, but the fresh weight of stems and leaves above the planting plate was the heaviest. In addition, below the planting plate the stem cuttings were longest and the root weight was heaviest at 60 μmol·m-2·s-1 LED light intensity. The number of stolons also differed between cultivars, but was greatest for seedlings raised at 60 μmol·m-2·s-1 LED light intensity, at 4.2/plant for ‘Sumi’ and 7.7/plant for ‘Chubaek’. At 60 μmol·m-2·s-1 LED light intensity, the tuber number and total tuber weight were the best, but the higher the light intensity, the smaller the total tuber number and total tuber weight for both cultivars. In conclusion, when producing potato stem cuttings for aeroponic systems using a closed-type plant production system, the most suitable LED light intensity for raising seedlings was found to be 60 μmol·m-2·s-1.